Diode and Diode Application

合集下载

APS医学工程课程介绍部分

APS医学工程课程介绍部分

1 医学超声仪器原理Principle of Medical Ultrasound EquipmentQ1: What is the ultrasound?A1: Ultrasound is a kind of high frequency sound waves (more than 20k Hz), belongs to a kind of mechanical wave.Q2: How ultrasound combined with medicine?(How clinical application?)A2: By launching a set of ultrasound machines, ultrasound will be reflected back when encountered the body or tumor.Doctors on the basis of the reflected sound waves infer the size and the location of the lesion or the tumor.Q3: How the ultrasound equipment launching ultrasound? How to accept ultrasound? A3: piezoelectric sensor (silicon)As sound-wave launching components, converts electrical energy to the high frequency vibration振动;As sound-wave receiving components, vibration cause by reflected sound will be converted to electrical signals.Q4: Compared with other medical detection (treatment) technology, what advantage does ultrasonic have?A4: Ultrasonic detecting almost no harm to human body, although it displays the image is not very clear.Q5: Ultrasonic is how to solve the lesion / tumor / calculus?A5: By carrying energy, ultrasound can shatter the lesion / tumor / calculus.Q6: How many types do the ultrasound equipment/medical ultrasounography have? What are their features (function)?A6: There are three main kinds of ultrasonic instruments .The type-B ultrasonic, the type-M ultrasonic, and the Color Doppler Flow Imaging (CDFI).Type-B ultrasonic can display the two-dimensional figure, for the fetus.Type-M ultrasonic can display the movement of the heartCDFI can show blood velocity, flow and stability.Q7: What is the component of Ultrasound Equipment?A7: Both of sound-wave launching component and receiving component is the part of ultrasonic probe (detection). They use the same structure such as Electronic linear array ultrasonic probe. It contains six parts: switch controller, damping pad, matching component, linear array sensor, sound lens, and hull.Switch controller is designed for focused ultrasound by time-delay circuit.Time-delay circuit (inductance(inductor) and 3-8 decoder)【图】Q8: How did you segregate the launching component and receiving component?A8: segregate circuit.【图】(diode and audion)Q9: What is the principle of CDFI?A9: It is basis on Doppler Effect. △f=2f·cosθ·(v/c)The frequency shift △f of reflected sound can show the velocity;Red color means the direction of blood cell is face to the ultrasonic probe.Blue color means the direction of blood cell is reverse to the probe.Green color shows the stability of the blood. (turbulence flow)Q10: What is the effect of the matching component?A10: Between the sensor and the object to keep a necessary distance.Because the sound field attenuation rule is like this.【图】2放射治疗设备原理Principle of Radiation Therapy EquipmentQ1: What is the radiotherapy? What is the principle of radiotherapy?A1: Use of high-energy rays (such as x-ray,ionizing radiation) to treat tumor.Q2: What are commonly used in radiotherapy equipment?A2: Kilo-voltage X-Ray therapy apparatusCobalt 60 therapy apparatusMedical linear accelerator(electron ray)Q3: What is a medical linear accelerator? What is its function?A3: First,we input higher voltage,for magnetron can generate the high power microwaveSecondly,electronic injector control the number and the speed of electronic into the medical linear acceleratorThirdly, electronic get energy to accelerate from the microwave in accelerator,to be high-power electron beam.Finally, the high-power electron beam shoots the Anode target, to produce the ray that we need.Q5: What is the process(step)of radiation therapy ?A5: Firstly, confirm the location of the tumor, and choose the way to radiation exposure. (Simulate it) We need avoid other healthy organs.Secondly, use computer to optimize therapeutic schedule.Thirdly, Use radiation(ray)to kill tumor (cancer).3医用X线机系统Medical X-ray Machine SystemQ1: What is the medical X-ray?A1:When the Electronic energy level(state)change ,it will radiated a kind of energywave. That is x-ray.Q2: How does the x-ray generate?A2: Electronic impacts (shoot) anode target (tungsten) from the cathode. Let it generate ionization and bremsstrahlung radiation, thus radiating x-rays.Q3: What is the role of the x ray?A3: Through the body, found the position of the disease.Q4: What are x-ray features (function)?A4: The medical x-ray has two models with radiography and fluoroscopy. Both models have some harm to human body.Radiography is very fast, the film is more clearly, but it has more radiation. It is often used to check the lungs and intestines.Fluoroscopy is slowly than radiography. It is often used to intervene in operation and physical examination.Q5: What is the principle of x-ray detection (diagnosis).A5: Different density organ has different x-ray absorption.Through the body, the x-ray project in the film. And then, through the observation of film, doctor found the position of the disease. (dark region and bright region)Q6: What is the advantage of X-ray?A6: The x-rays have some harm to human body, but it’s far less than CT.And the x-ray machine is very cheap and simple.Q7: What are the names of these various x-ray machines? What are the different of clinical application?A7: Mammography is for breast. We need change the filter so that generate the x-ray which fit human breast.Dental X-ray unit gives the examination of the teeth. It can give a panoramic x-ray of all the teeth at once. It removes around your head at the section of your teeth. Angiography: Doctor injects contrast media in the blood vessel. This way can enhance the contrast between the blood vessel and background.Q8: What is CR? What is DR?A8: DR is digital radiography; CR is computed radiography.DR is base on A-Si (Amorphous Silicon), x-ray can be converted to electric signal. CR likes detector of CT.4 CT成像原理与技术(Computed tomography Principles)Q1: What is the basic of physical principles of CT?A1: Electronic impacts (shoot) anode target (tungsten) from the cathode. Let itgenerate ionization and bremsstrahlung radiation, thus radiating x-rays.Q2:What is the CT Components(part)?(How many stage does CT have?)A2: There are three section(stage):data acquisition, image reconstruction and image displayThe data acquisition contains a lot. There are mainly four parts: x-ray frame (tube), filter, collimator and detector.Q3: What is the Reconstruction algorithms(CT image Reconstruction)?A3: Detector gets different angles of projection, so that sinogram is formed.The algorithms that use sinogram to reconstruct object is called reconstruction algorithms.Reconstruction algorithms includes a lot,such as filtered back-projection(FBP), FT reconstruction and iterative reconstruction.【图】Iterative reconstruction is used for low dose reconstruction.Q4: What is the image artifact?A4: Artifacts are that reconstruction image appears something which does not exist in object.Q5: How to make the image clearer?A5: Improve SNR(signal to noise ratio),Eliminate artifacts, improve HCR(high contrast resolution), and so on.①Improve SNR: Improve the thickness of scan, because it will improve the signal that detector acquire. This way applies to get the image of smaller different of density. And we also can reduce noise by digital image processing.②Eliminate artifacts: If we find that there was a line but not cosine(sine), that need be eliminated. Because it will cause the ring artifacts.③Improve HCR: Reduce the thickness of scan, because it will improve the accuracy. This way applies to get the image of larger different of density, such as lungs and bones because they have high contrast. Reduce the size and interval of detectors. Reduce the size of focal spot of x-ray.Q6: How the detector to get projection? What is the structure of data acquisition?A6: The x-ray frame removes around human body, and the opposite detector receives the x-ray which through the human body. Thus how to detector get projection.Q7: What is the different between the FBP and FT?A7: FBP is used to star artifacts in back-projection. Before the back-projection, we need processing the projection of that angle with the help of filter. (star artifacts at the center of image)FT is using Fourier transform to reconstruct the object. 【图】【BP greatest common divisor at last】Q8: How is the collimator and detector work?A8: Collimator, eliminate scattered rays. And detector contains photomultiplier tube. The photons impact the cathode, let it produce a little electron. With the help of electric field to accelerate it, finally the anode of photomultiplier will produce lots of electrons. 【detector: CsI NaI They are chemical elements.】Q9: What is the function of filter?A9: Eliminate the frequency which we don’t need.5 MRI原理与技术(MRI principle and technology)Q1: What is the basic of physical principles of MRI? (NMR)A1: MRI is magnetic resonance imaging. The physical principle is called NMR. Firstly, some atoms (such as hydrogen atom) in the static magnetic field produce Larmor precession.Secondly, when we give it a radio frequency (RF) field, which conform to [formula], NMR will happen. (The spin of atom fall down; RF is a kind of excitation) Thirdly, when the radio frequency field stop, the atom will return to the Larmor precession state, called a relaxation process, it will produce some medical signals, such as T1, T2 and PDW (proton density weighting).Q2: What kind of image does the MRI produce?How to produce this image?A2: two-dimensional images at any angle of the plane, even three-dimensional images.Imaging objects are spatially encoded by gradient magnetic fields.Spatial encoding contains three steps: Slice gradient, Phase gradient and Readout gradient. They let different location of the atomic produce different signal.Signal receiving coil will decode signal in space k, and with the help of Fourier inverse transform presented in the end.【公式:y=Acos(ωx+φ)】Because of the slice gradient magnetic field, we can just let atoms in one plane to produce signal. And with the help of Phase and Readout gradient magnetic field, we can let different location of atoms of this plane generate different signal. In x-direction, different location atom has different ω;in y-direction, different location atom has differentφ. (ωincrease along the x-direction; φincrease along the y-direction)ωis the frequency of atom-spin; φis the phase-difference of atom-spin.Q3: What is the space k? How is it work? 【不问不提】A3: Space k stores the information of image. Near the outside of space k is the high frequency information that determines the HCR of image. The centre of the space k is the low frequency information that determines the SNR of the image.【追问再说】Actually the phase gradient field will repeat many times but through differentphase-difference gradient field.【图】Because high phase difference contributes to improve the HCR of image, and low phase-difference contributes to improve the SNR of image.Q4: What are the different between the MRI and CT?A4: MRI is based on the principle of NMR phenomenon; but CT is based on the characteristics of X-ray.MRI has excellent HCR (high contrast resolution).MRI of the harm to human body is less than CT.MRI is more expensive.MRI can get the two-dimensional images at any angle’s plane of body; while CT just can get cross sectional image.Q5: How to make image clearer? Eliminate artifacts?A5: If we use high intensity of phase gradient, that will improve the HCR of image.If we use low intensity of phase gradient, that will improve the SNR of image.About the movement artifacts, we can use Gating Technique, receive the signal just in calm period.6 现代检验医学仪器(Medical Laboratory Instruments)Q1: What kind of the clinical laboratory instrumentation?A1: hematology analyzer, flow cytometer (FCM), blood gas analyzer, urine analyzer, biochemical analyzerQ2: What are their purposes?A2:①Hematology analyzer: Classify blood cells and countingPrinciple: tiny particles through special holes can cause solution resistance of hole change②Flow cytometer: Fast measure the physical and chemical properties of cell【图】③Blood gas system: through testing the blood and breath gas, we can analyze the acid-base balance and oxygen state【图】④Urine analyzer:urine in the reagent with different color causes different light reflectivity,so as to determine the indicators of urine【图】⑤Biochemical analyzer:Analyze blood and other body fluids by using a set of automation equipments to determine various biochemical indicators【图】Principle:photoelectric colorimetric technique( Lambert-Beer's Law)【A=kbc; A→absorbance; k→constant; b→thickness; c→concentration】7 医用传感器medical sensorsQ1: What kind of medical sensors are thereA1: resistive sensor (capacitive sensor, inductive sensor), piezoelectric sensor,magnetic sensor, thermoelectric sensor, optical sensorsQ2: What is the principle of these sensorsA2:①Resistive sensor: When strain gauge changes shape, the resistance will change. This change will be obviously detected by resistive Wheatstone Bridge.capacitive sensor,inductive sensor:The resistance is replaced by capacitor or inductor and it can improve sensitivity.【图】②Piezoelectric sensor: Pressure can be converted to electrical signal and output by using piezoelectric sensor.(be used in ultrasound instrument)③Magnetic sensor: Using the hall element, magnetic field intensity can be converted to electrical signal output.④Thermoelectric sensor(thermocouple): Basis on Seebeck effect【图】,sensor can sense difference in temperature and Converted to electrical signal output.⑤Optical sensors: Using the photoelectric effect,the optical signal is converted into electrical signal output.8 现代医学电子仪器原理与设计Principle and Design of Medical Electronic InstrumentationQ1: What the principle should be followed when medical electronic instrumentation design?A1: High CMRR (common mode rejection ratio), such as amplify circuit.High sensitivity, such as emitter follower/Wheatstone BridgeLimit the noise (more important than amplifying signal), such as LPF/differential amplifier circuit (zero drift noise) or software processingEnsure it conform to EMC, energy dissipation circuitEnsure it conform to safety standards of human bodyQ2: What the different between the interference and noise.A2: Interference: From the outside of the test systemNoise: From the test system, from itselfQ3: What is the EMC? (Explain it)A3: EMC is Electro Magnetic Compatibility.On the one hand, it must restrain the interference from outside.On the other hand, it must restrain itself to interfere others equipment.Q4: How to design a medical electronic instrumentationA4:【图】Signal acquisition, signal preprocessing, signal processing, feedback/control, stimulation, signal calibration, records, data saveFor example: In the morning, engineer will use water phantom to check the CT. Signal preprocessing: such as detector of CT9 Linear Algebra 线性代数A:In this course, we mainly study what is matrix, how to operation it. Because matrix is the basis of image reconstruction in CT. By the way, we can also use Matlab for matrix operation. It is useful software.Matrix: be used to solve difficult equations.10 Complex function and integral transform 复变函数A: In this course, we have learnt Fourier transform; it is the basis of signal courses, such as DIP, DSP and so on.11 Probability Theory and Mathematical Statistics 概率论A: In this course, we mainly study probability distribution such as Gaussian distribution. It is the basis of DIP; especially reduce noise, because noise is random. 【看情况说】We also learnt histogram, with the help of histogram, we can processing the digital image very easy.10 病理学Pathology 生理学PhysiologyQ1: What is the different between the Physiology and Pathology?A1: They all introduce the human organs simply. But Physiology studies the healthy state of human organs while Pathology studies the unhealthy state, the pathological reaction of organ.Q2: Do you know what pathological reaction does the organ happen?A2: The cell will have adaptive changes when it is injured.But when it breakthrough the limitation, cells can appear damage, and eventually death.Finally, organs will be in the form of regeneration or fibrous repair to repair themselves.Q3: I notice your scores of Physiology and Pathology is lower, do you have any reasons about that?A3: Because the pathology and Introduction to Clinical Medicine involves knowledge is too complicated, and this course don’t have many relationships with my major (research direction).【prepare】肠道intestinal tract 胃stomach 肌肉muscle 心脏heart大脑brain 肺lungs乳房breast 胸腔chest 骨bones13 An Overview of clinical Medicine 临概systematic anatomy 系解Q1: What knowledge does An Overview of clinical Medicine introduce to you?A1: Simple to outline some of the human body system:Motor system, digestivesystem, respiratory system, blood circulatory system, nervous system, urinary system, reproductive system, endocrine systemQ2: What did you know from the systematic anatomy?A2: The name of bones and muscles. Outline the organs human have and function of them. Such as intestinal tract belongs to gas-containing organs, so we can use ultrasound instrument for diagnosis. And bone is a kind of high density organ, so we can use x-ray for diagnosis.14 The Recognition and Nursing of common clinical symptoms 临床症状识别Q1: If patient have some clinical symptoms, how to diagnose it? Use what medical facility?A1: If we want to recognize/diagnose clinical symptoms, firstly we need know the location of symptoms and what system it belongs to.【临概、系解也可套用】Such as headache, because it belongs to nervous system and our brain have many complex structures, so we need use CT or MRI. (The HCR of MRI is good than CT, but expensive)Such as cough, because it belongs to respiratory system and the density difference between the lungs and bone is high enough, so we can use x-ray. But if there maybe has a tumor, we have to use CT for diagnosis.Secondly, we need ensure the period of disease. Such as cancer, if it is early period, we just need use medical instrument to ensure the location and size of tumor and cut it by operation. But if it is later period, maybe we must use radiation therapy. 【病理也可套用】【prepare】Because it is optional course and do not have many relationship with my major, so we just need to know the outline of it. 【案例分析也可套用】15 Legal Analysis of Typical Case about medicalA: In Wuhan, there was a woman, be checked by CT and found a shadow behind breastbone. It was doubted a tumor and use radiation therapy for a long time. Finally, the hospital found it is misdiagnosed, it’s not tumor. And hospital has to refund to that patient. But doctor didn’t have fault although it’s misdiagnose. Because that shadow, nobody can insure it is a tumor or not, doctor just could say “maybe is a tumor, maybe not”. So as a biomedical engineer, we should make the medical instrument better for reducing the artifacts and make the image clearer.16 电子技术试验Electric Technology ExperimentQ1: What experimental/laboratory apparatus did you use?A1: Signal generator,Oscilloscope, Circuit element (resistance capacitor inductor diode audion)Q2: What experiment did you do?A2: Emitter follower, Differential amplifier, integrated operational amplifierQ3: What did you learn from these experiments?A3:①Emitter-follower: Let the output voltage follow the input voltage linear change in a wide range②Differential-amplifier: Amplify different-mode signal, restrain common-mode signal③Integrated operational amplifier: Use it to proportion, addition, subtraction, integral operation17 C Language Programming 面向对象程序设计object oriented programmingQ1: What is the different between the C language and C++?A1: c++ can run most of c code while c cannot run c++ code.C is function-driven while c++ is object-driven.In the case C, the program is formulated step by step, each step is processed into detail. While in c++, the base elements are first formulated which then are linked together to give result to larger system.Q2: Can you write a program?A2: If we want to compare figure a and b, and put out the maximun.If we use c language:#include<stdio.h>main (){int a,b,max;printf(“input 2 numbers :”);scanf(“%d%d”,&a&b);if (a>=b) max=a;else max=b;printf(“the maximum is :%d”,max);}If we use c++ language:#include<stdio.h>int max(int a,int b){if a>=b return a;else return b;}main(){cout<<“input 2 numbers:”;int a,b;cin>>a>>b;cout<<“the maximum is :”<<max(a,b);}附:%d is a kind of data typea b max is the name of where store the data.18 Quality System and Regulations of Medical DeviceA: According to Chinese law, the supervision for quality of the medical instruments in different stage is the responsibility of different government departments. The stages of registration and production are the responsibility of CFDA; the stages of installation and usage are the responsibility of MOH. The organization which tests the quality of the medical instruments must be accredited by the CNAS.About the classification of the medical instruments and laws, regulations (such as GB9706 and YY0505)are constantly updated by the government. So we just need log into the website of CFDA and MOH, and then we can get the latest information about the instrument.Q1: What is different between the Quality System and Testing Technology?A1: Quality System of Medical Deice pays attention to the law and regulations about medical device. While Testing Technology of Medical Equipment pays attention to how to test parameters and test what parameters of medical equipments.19 Testing Technology of Medical EquipmentA: There are common requirement and special requirement about the medical instruments. Under normal conditions, we consult handbook such as Security manual to test the medical equipment.About common requirement, for example“test in single fault condition”. Firstly, we need to make a failure (disconnect the protective earthing line or input a interference signal), and then testing instrument is still safe to human body.About special requirement, for example“the voltage of x-ray tube”, we usually use “Non-intrusive testing of the tube voltage”. Use different thickness of the filter and the radiation detector. Under the condition of different thickness of filter, record the corresponding radiation attenuation degree. Finally by corresponding relation, we can know the voltage of the X-ray tube.【prepare】“CT radiation dose testing” Pencil ionization chamberThrough CTDI to shows radiation dose of CT“HCR of CT” phantom of line pair“Testing the thickness of CT scan” phantom of sheetmetal20 Technical DrawingThree view drawing (top view, front view, side view) Cross-section viewDiameter Length Width Height。

电子技术专业英语

电子技术专业英语

1、汉译英1)直流电路direct current circuits2)放大器(扩音器)amplifier3)模拟电子技术analog electronics4)半导体二极管semiconductor diode5)晶体管效应transistor effect6)微解决器microprocessor7)电气工程electrical engineering8)能源工程(或电力工程)power engineering9)通信工程telecommunications engineering10)内部器件internal devices11)电子元件electrical components12)欧姆定律Ohm law13)限制电流limit current14)分压器voltage divider15)晶体管偏置电路transistor biasing circuits16)阻碍电流block DC current17)存储点能store electrical energy18)感抗inductive reactance19)绝缘材料insulating material20)交流阻抗AC resistancea)通用仪表general-purpose meterb)模拟仪表analog meterc)互换测试笔reverse the test leadsd)机械调节mechanical adjuste)测量电阻measure resistancef)正向电压positive voltageg)测量电流measure currenth)电压幅度voltage amplitudei)双踪示波器dual-trace oscilloscopej)信号发生器signal generator21)PN结PN junction22)三极管bipolar transistor23)电子和空穴electron and hole24)稳压电源electronic power supply或steady DC voltage source25)桥式整流器bridge rectifier26)脉冲直流电pulsating DC27)二极管的正极anode of diode28)峰值电压peak voltage29)电容滤波器capacitor filter30)充电和放电charge and discharge31)稳压管Zener diode32)电器电子工程师学会IEEE(Institute of Electrical and Electronics Engineers)33)专业技术组织technical professional association34)基尔霍夫电压定律Kirchhoff’s V oltage Law35)电压源voltage sources36)电荷守恒定律the law of conservation of electric charge37)在每一瞬时at every instant of time38)元件两端的电压voltages across elements39)无线电传输radio transmission40)频率调制或调频frequency modulation41)频域the frequency domain42)线性电阻linear resistor43)调幅波形amplitude modulation wave44)专用集成电路(ASIC)45)快速时间响应fast response time46)有效信号valid signal47)十进制数字系统decimal system48)逻辑运算logic operation1)控制信号线the control bus2)中断线interrupt lines1)结构化语言structured language2)局部变量local variables3)副作用side effect4)汇编语言指令assembly language instructions1)静止图像still image2)阴极射线管,显像管CRT or the cathode ray tube3)像素pixel4)电子束electron beam2、英译汉1)assembler language汇编语言2)alternating current circuits交流电路3)passive electrical circuits无源电路4)three phase circuits三相电路5)digital electronics数字电子技术6)logic gates逻辑门7)3D virtual reality image三维虚拟图像8)computer programming计算机编程9)major in(在大学里)主修10)advanced programming techniques高级编程技术1)known as capacitive reactance称为容抗2)with units ohms单位为欧姆3)prevent device from burning out防止器件烧掉4)has an AC resistance to AC current对交流电流由阻抗5)adjustment with a screw用一个螺丝调节6)in the shape of a cylinder 呈圆柱形式7)block DC current,but pass AC current阻直流通交流8)to vary the inductance改变电感9)be given by the formula 由公式给出10)the RF amplifier 音频放大器1)analog multimeter模拟万用表2)extended range扩展范围3)specific meters特殊仪表4)includes the function and range switches具有功能及范围选择旋钮5)present an electronic picture呈现一幅电子图像6)display the voltage waveform显示电压波形7)appear on the screen在屏幕上出现8)phase relationships相位关系9)an example例如,作为一个例子10)in series with the circuit串连接入电路1)Semiconductor material半导体材料2)forward biased正向偏置3)depend on the external circuit resistance取决于外部电路的电阻4)excessive reverse-biased voltage过高的反偏电压5)is directly proportional to the amount ofbase current是正比于基极电流6)may even appear almost as a short几乎可当作是短路7)cause stability problems for a transistorcircuit引起晶体管电路的稳定性问题8)digital technology数字技术9)the most popular technology最常用的技术10)use two complementary typeset oftransistors N-channel and P-channel用两种互补型的晶体管——N沟道和P沟道1)equipment operation设备的运营2)device that converts AC into DC把交流电转换成直流电的器件3)the power lines电源线4)depending on the value of DC voltageneeded 根据所需要的直流电压值5) a half-wave rectifier平波整流器6)so as to produce a constant DC output从而产生一个稳定的直流输出7)in the negative side of the capacitor在电容的负极8)flow through the load流过负载9)in the forward-biased condition在加正向偏置电压的条件下10) a series(current-limiting)resistor一个串联(限制电流)电阻1)current source电流源2)under this circumstance在这种情况下3)present the second of Kirchhoff’s laws给出基尔霍夫第二定律4)introduce the concept of a “loop”引入“回路”的概念5)An alternative statement of KVLKVL的另一种表述法6)voltages algebraically sum电压代数和7)sinusoidal steady-syate response正弦稳态响应8)ordinary household voltage平常用电的电压9)time-invariant circuit时不变电路10)percentage of modulation调制比例reduce the power consumption减小消耗功率flip-flop 触发器the octal and hexadecimal systems当时钟脉冲信号来届时改变状态①直流电路direct current circuits②放大器(扩音器)amplifier③欧姆定律Ohm law④正极positive electrode⑤充电与放电Charge and discharge⑥无线电传输Radio transmission⑦模拟仪表Analogue Meters⑧模拟电子技术analog electronics⑨半导体二极管semiconductor⑩晶体管效应transistor effect⑪微解决器microprocessor⑫通信工程telecommunications engineering ⑬汇编语言assembler language⑭电子元件electrical components⑮限制电流limit current⑯分压器voltage divider⑰偏置电路biasing circuits⑱阻碍电流block DC current⑲感抗inductive reactance⑳容抗capacitive21正向电压positive voltage22扩展范围extended range23电压波形voltage waveform24连接入电路in series with the circuit25PN结PN junction 26三极管bipolar transistor27电子与空穴electron and hole28半导体材料semiconductor material29正向偏置forward biased30数字技术digital technology31桥式整流器bridge rectifier32稳压管Zener diode33电源线the power lines34在电容的负极in the negative side of the capacitor 在加正向偏置的条件下in the forward-biased condition一个串联电阻 a series (current-limiting)resistor35电压源voltage sources36在每一瞬时at every instant of time37无线电传输radio transmission38频率调制或调频frequency modulation39快速时间响应fast response time40有效信号valid signal41结构化语言structured language42局部变量local variables43副作用side effect44静止图像still image45阴极射线管pixel 46电子束electron beam1.resistors are used to limit current flowing to adevice ,thereby preventing it from burning out, as voltage dividers to reduce voltage for other circuits, as transistor biasing circuits, and to serve as circuit loads.电阻常用做限流器,限制流过器件的电流防止烧坏器件,电阻也可用作分压器,以减小其他电路电压,还可以用在晶体管偏执电路中和作为电路负载。

Diode应用

Diode应用

7. Rectifier
倍壓器
5sin(120t) 1 C1 2 K D1 C2 A 1 A D2 K 2
負半週 工作
正半週 工作
BQ24740 Boost
BQ24740RHDR spec.pdf
=5V+ Vph
What Risk we meet ?
VIN L14 BLM21PG220SN1DGP DCIN1 3 4 6 1 5 2 7 9 8 SKT-JACK-329-GP 22.10037.I11
SMART1 12 10 9 8 7 6 5 4 3 2 1 11 PTWO-CON10-4-GP 20.K0382.010
2
2
2
4
5
SC_DATA SC_CLK SC_RST C282 SC12P50V2JN-3GP SC12P50V2JN-3GP 2 1 1 C283 SC12P50V2JN-3GP 1 C284
BAV99W1.pdf
Artemis ESD Issue.ppt
What Risk we meet ?
Over Voltage , Over Current , Over temp.
相關的案例(1)
KBC issue
There were high F/R of KBC pin24(Brightness),pin33(EC_BLON) in Vega and Stardust, And the FA report were always EOS or ESD, So we add the ESD Diode in Viking and Spirit.
V=2.87V V=?
V(battery)=3V
S3 power

手机维修术语中英文对照表

手机维修术语中英文对照表

AA 模拟AB 地址总线 ACCESSORIES 配件ABB 模拟基带信号处理器AC 交流ACCESS 接入ADC 模拟到数字的转换ADDRESS BUS 地址总线AF 音频AF 音频AFC 自动频率控制AFPCB 音频电路板AGC 自动增益控制AGND 模拟地ALARM 告警ALERT 振铃ALRT 铃声电路ALRT—VCC 振铃器电源AMP 放大器AMPS 先进的移动电话系统ANT 天线ANTSW 天线开关AOC 自动功率控制AOC-DRIVE 自动功率控制驱动APC 音频处理芯片ASIC 专用应用集成电路AUC 鉴权中心AUDIO 音频AUTO 自动AUX 辅助AVCC 音频供电A/D 模拟/数字转换A/L 音频/逻辑板APC 自动功率控制BBIT 比特BACKLIGHT 背光BURST 突发脉冲串BCCH 广播信道BW 带宽BUSY 忙BUS 总线BARRING 限制BCD 二/十进制码BPF 带通滤波器Block Digram 方框图Backlight 背光Base Band 基带(信号)BATT+ 电池BATTERY 电池BIC 总线接口芯片BS 基站BUZZ 振铃BDR 接收数据信号BDX 发送数据信号BKLT—EN 背景灯启/闭控制BALUN 平衡/不平衡转换BCH 广播信道BDR 接收数据信号BDX 发射数据信号BIAS 偏压CCARD 卡CLONE 复制CODE 代码CONNECTOR 连接器CONTACT SERVICER 联系服务商CONTROL 控制COUPLING 耦合CRYSTAL 晶体COVER 覆盖CP 表示鉴相器的输出端CP—RX RXVCO控制信号输出CP-TX 发射VCO控制输出端CPU 中央处理器CRYSTA 晶振CS 片选CS FLASH 闪存片选CS RAM 随机存储器片选CS ROM 只读存储器片选CAR 电压控制/音频/振铃模块CCH 控制信道CDMA 码分多址CONVERTER 变频器CPU 中央处理器CHARGE 充电CLK OUT 逻辑时钟输出CLK SELECT 时钟选择信号CODEC 编码CP-RX RXVCO 接收锁相压控振荡器CP-TX TXVCO 发射锁相压控振荡器CHARG 充电电源负端CHARG+ 充电正电源CHECK 检查DDB 数据总线DTMF 双音多频DTX 非连续发送DATA 数据DISABLE 禁用DISTORTION 失真DEINTERLEARING 去交织DECIPHERING 解密DBB 数字基带信号处理器DC 直流DCIN 外接电源输入DCON 直流接通DCS 数字通信系统DCSPA 功率放大器输出的DCS信号DCSRX DCS射频接收信号DCS-SEL DCS频段选择信号DEMOD 解调DET 检测DFMS 来数据信号DGND 数字地DIGITAL 数字DIODE 二极管DISPLAY 显示DM-CS 片选信号DP-EN 显示电路启动控制DSP 数字语音处理器DTMS 到数据信号D-TX-VCO DCS发射VCO切换控制DYNATRON 晶体管DUPLEX 双工Duplex Saparation 双工间隔DCS-LNA275 1800MHz低噪声放大器电压(2.75V)DCS—SEL 频段选择信号之一(1800MHz)DCS-VCO RXVCO频段切换控制信号之一(1800MHz)DEMODULATION 解调DM-CS 发射机控制信号,控制TXVCO和I/O调制器DP—EN 显示电路启动控制D-TX—VCO 1800MHz发射压控振荡器EEAR 听筒E-TACS 扩展的全接入通信系统ESN 电子串号E2PROM 可擦写可编程只读存储器EPR 有效辐射功率ENABLE 启用EQUALIZER 均衡器EAR 耳机EL 发光EN 使能ENAB 使能ERASABLE 可擦写EXC 外部EXT 外部的EXT-B+ 外接电源、充电电压输入FFDMA 频分多址FULL DUPLEX 全双工FACCH 快接入控制信道Freq。

汉中市人民政府关于表彰第十一届自然科学优秀学术论文的通报

汉中市人民政府关于表彰第十一届自然科学优秀学术论文的通报

汉中市人民政府关于表彰第十一届自然科学优秀学术论文的通报文章属性•【制定机关】汉中市人民政府•【公布日期】2018.08.09•【字号】汉政函〔2018〕44号•【施行日期】2018.08.09•【效力等级】地方规范性文件•【时效性】现行有效•【主题分类】教育正文汉中市人民政府关于表彰第十一届自然科学优秀学术论文的通报各县区人民政府,汉中经济开发区管委会,市政府各工作部门、直属机构:近年来,全市上下认真实施“科教兴汉”、“人才强市”战略,全市广大科技工作者潜心钻研,大胆创新,取得了一批自然科学成果及优秀学术论文。

根据《汉中市自然科学优秀学术论文评选办法》,经汉中市第十一届自然科学优秀论文评选委员会评审,评选出本届自然科学类优秀学术论文102篇。

其中:《HCV感染者中血清外泌体miRNA-122的检测及其临床意义》等10篇论文评为一等奖;《不同分子分型的乳腺癌前哨淋巴结转移与临床病理特征的关系研究》等41篇论文评为二等奖;《不同性诱剂对亚洲玉米螟的引诱效果比较及田间应用初探》等51篇论文评为三等奖。

为了鼓励全市科技工作者不断加强学术创新,为促进汉中“三市”建设和经济社会持续科学发展做贡献,市政府决定对全市第十一届自然科学优秀学术论文及作者予以表彰。

希望受到表彰的同志再接再厉,不断探索奋进,在各自工作领域作出新的更大成绩。

全市科技工作者要向受表彰的同志学习,紧紧围绕我市科技、经济、社会科学发展的重大课题,深入研究,克难攻关,锐意进取,多出成果,全面推进我市科技进步和经济社会又好又快发展。

附件:汉中市第十一届自然科学优秀学术论文获奖名单汉中市人民政府2018年8月9日附件:汉中市第十一届自然科学优秀学术论文获奖名单一等奖论文(10篇)论文名称HCV感染者中血清外泌体miRNA-122的检测及其临床意义carcinoma identified by cross talk genes in disease related pathways 通过疾病相关通路的串扰头皮轴型血管网皮瓣或带阔筋膜的股前外侧穿支皮瓣修复头皮恶性肿瘤患者根治性切除术缺损的效果籼稻骨干亲本稻瘟病抗性基因pi-b的检测基于STR分型检测技术的89份茶树种质资源遗传多样性分析秦巴山区黄牛群体的微卫星DNA遗传多样性陕南老茶树扦插茶苗资源遗传多样性分析原位水热法在介孔TiO2光阳极中生长ZnO纳米线增强量子点敏化太阳能电池的光捕获dots and their application in constructing a fluorescent turn-on nanoprobe for imaging of 荧光碳点的制备及在构建细胞内硒醇纳米探针中的应用)Interfacial properties of stanene–metal contacts(锡烯与金属接触的界面性质)二等奖论文(41篇)不同分子分型的乳腺癌前哨淋巴结转移与临床病理特征的关系研究might participate in protecting the pupating larva from microbial infection(家蚕茧丝中的蛋白染)汉中市中心城区常绿行道树综合评价is associated with the risk of intrahepatic cholangiocarcinoma MicroRNA-150在胆管细胞性肝癌秸秆还田对汉中盆地稻田土壤有机碳组分、碳储量及水稻产量的影响大棚温湿条件对草莓生长结实及土传病害的影响西瓜雄性不育系“se18”抗氧化酶活性和内源激素含量变化分析汉中面皮水磨米粉的加工技术优化研究三倍体毛白杨生长量数学模型建立及验证抗凝剂对动物布鲁氏杆菌病虎红平板凝集试验的影响421CC were significantly Associated with longer progression-free survival in Chinese breast 应用液相阻断EISA试验和正向间接血凝试验(IHA)检测猪(O)型口蹄疫抗体的比较分析机插秧不同插植密度对水稻纹枯病发生及危害影响的初步研究不同栽培规格对魔芋根状茎生长特性及产量的影响6个蓝莓品种在汉中地区的丰产性试验不同厂家猪O型口蹄疫灭活苗免疫效果研究城固县农作物病虫害绿色防控技术示范实践探索地佐辛治疗晚期癌症患者伴中度及中度疼痛的疗效及安全性观察籼粳交水稻花药培养条件的优化不同果桑品种资源的生长结实特性调查初报可见分光度法在布鲁氏杆菌病试管凝集试验结果判定中的应用不同基质对曼地亚红豆杉扦插成活率的影响MODS患者外周血单个核细胞内PPARγ与NF-κB的表达和关系两种不同途径胆道金属支架植入治疗恶性阻塞性黄疸的对比研究腔镜保留残胃的双通道重建术在食管胃结合部癌中的应用mphocyte ratio improves the predictive power of GRACE risk score for long-acute coronary syndrome 血小板与淋巴细胞比例改善GRACE风险评分对急性冠状动脉综合征患者长期心血管小儿颈深部感染33例分析早期24h内血浆BNP动态变化与重症急性胰腺炎近期死亡的相关性研究the Interface Optical Phonon Spectrum in Wurtzite GaN/AlxGa1?xN Quantum Wells 中文:纤锌矿xN 的界面光学声子谱及其混晶效应阴道镜Reid评分对HIV阳性妇女宫颈癌筛查的诊断价值新方法初治结核性胸膜炎的疗效观察对有乳头发育的乳头内陷采用钢丝十字交叉牵引矫正术的临床体会electrochemical performance of Al-doped ZnO thin films hydrothermally grown on graphene-te bilayer flexible substrates (PET?石墨烯双层柔性衬底上水热生长Al掺杂ZnO薄膜的光电和电化学性基于图像技术的空中加油辅助指引系统via scanning a one dimensional linear unfocused ultrasound array 基于非聚焦多元线性阵列探汉中市空气污染特征及其气象条件分析f Well-Aligned ZnO Nanorod Arrays by Chemical Bath Deposition for Schottky Diode Applicatio陕钢集团烧结配加兰炭的工业试验lic acids and fluorescence properties in the solid state (苯并[c]香豆素羧酸衍生物的合及固体human immunoglobulin G: Elucidation of the cytotoxicity of CNPs and perturbation of immunog颗粒与人免疫球蛋白之间的相互作用:碳纳米颗粒的毒性及其对人免疫球蛋白构象影响的研究)ness of TC4-Based Laminated Composites Reinforced with Ti Aluminide and Carbide (TiAl合金层复合板材的弯曲强度和断裂韧性)三等奖论文(51篇)不同性诱剂对亚洲玉米螟的引诱效果比较及田间应用初探甘蓝型半冬性三隐性细胞核雄性不育系SY12A的选育秦巴山区珠芽魔芋种芋繁育方法比较及示范植酸与植酸酶在家禽生产中的应用研究缓释肥对机插稻生长发育及产量的影响中山柏苗木大小与移植成活率的关系汉中超级稻品种筛选试验汉中市元胡种植气候区划奶牛结核病PPD皮内变态反应检测技术应用中的问题讨论汉中茶树病虫害绿色防控存在的问题及对策汉中市森林生态文化体系建设规划与思考汉中水稻机械插秧插值深度试验初报喷施不同浓度的氨基寡糖素对柑橘生产的影响齐口裂鳆鱼人工繁育技术研究小麦茎基腐病的初步研究黄连木矮化林分的建设与探讨汉中水稻机械化插秧适宜新品种筛选试验初报汉中盆地水稻土有机质状况分析研究新型大鲵仿生态繁殖池建造结构及使用方法不同育秧剂对陕南稻麦油两熟区机插秧秧苗素质与栽插质量的影响一例鸭舟形嗜气管吸虫病诊断与治疗热疗联合FOLFOX4方案治疗晚期原发性肝癌的临床观察陕南油菜机械化生产现状及关键技术汉江河滩林下段木香菇高效栽培技术探讨一起疑似鸡白痢的诊治体会不同质量的魔芋球茎及药剂处理对魔芋软腐病田间控病保苗效果研究血栓弹力图在隧道式带涤纶套导管血栓栓塞中的作用晚期鼻咽癌同步放化疗临床研究以肺外症状为首发表现的儿童肺炎支原体感染85例特征分析改良预埋球囊技术对分叉病变分支小血管保护的临床疗效观察免散瞳数码眼底照相在老年眼底病中的筛查价值成人噬血细胞综合征8例临床分析普通型骨水泥股骨头假体置换与内固定治疗老年股骨粗隆间粉碎性骨折的对比研究喜炎平注射液联合小儿豉翘清热颗粒治疗儿童急性上呼吸道感染的临床研究某三级综合医院住院患者医院感染情况调查外源H2O2对低温胁迫下柑橘叶片抗寒性的影响近10年汉台区酸雨变化特征及气象条件分析具有最小荧光响应伪影的低亲和锌传感器汉江上游纤毛虫群落结构及与环境理化因子的关系汉钢1号高炉延长寿命的途径探析依帕司他联合甲钴胺治疗糖尿病周围神经病变的疗效及复发率pBabe-GLS1 真核表达载体构建及其对结肠癌细胞增殖、谷氨酰胺摄取的影响中医综合外治法治疗婴幼儿伤食泻254例临床观察儿童面部擦伤后真菌感染1例with cyclopentanone and furfural derived from Hemicellulose (用来源于半纤维素的环戊酮与糠料前驱体)开口箭大小孢子发生及雌雄配子体发育研究oil and its effects on microbial communities metabolism and enzyme activities (汉江上游铁壤微生物群落代谢和酶活性的影响)GaN:Mn 纳米粒子的磁性量子隧穿效应SBA-15 with thick pore wall and high hydrothermal stability (厚孔壁高水热稳定性SBA-15的合单侧开窗减压椎间融合内固定治疗老年退行性腰椎管狭窄症辛伐他汀对尿毒症患者微炎症的影响。

candence ORCAD常用元件中英文对照

candence ORCAD常用元件中英文对照

Cadence常用器件中英文对照表在cadence 安装目录下文件夹\Cadence\SPB_16.6\tools\capture\library 中有如下常用库,只是部分常用的库,还有很多不常用的也都在目录下面,1、AMPLIFIER.OLB共182个零件,存放模拟放大器IC,如CA3280,TL027C,EL4093等。

2、ARITHMETIC.OLB共182个零件,存放逻辑运算IC,如TC4032B,74LS85等。

3、ATOD.OLB共618个零件,存放A/D转换IC,如ADC0804,TC7109等。

BUS4、DRIVERTRANSCEIVER.OLB共632个零件,存放汇流排驱动IC,如74LS244,74LS373等数字IC。

5、CAPSYM.OLB共35个零件,存放电源,地,输入输出口,标题栏等。

6、CONNECTOR.OLB共816个零件,存放连接器,HEADER,CON AT62,RCA JACK等。

7、COUNTER.OLB共182个零件,存放计数器IC,如74LS90,CD4040B。

8、DISCRETE.OLB共872个零件,存放分立式元件,如电阻,电容,电感,开关,变压器等常用零件。

9、DRAM.OLB共623个零件,存放动态存储器,如TMS44C256,MN41100-10等。

ELECTRO10、MECHANICAL.OLB共6个零件,存放马达,断路器等电机类元件。

11、FIFO.OLB共177个零件,存放先进先出资料暂存器,如40105,SN74LS232。

12、FILTRE.OLB共80个零件,存放滤波器类元件,如MAX270,LTC1065等。

13、FPGA.OLB存放可编程逻辑器件,如XC6216/LCC。

GATE.OLB共691个零件,存放逻辑门(含CMOS和TLL)。

14、LATCH.OLB共305个零件,存放锁存器,如4013,74LS73,74LS76等。

二极管过压失效模式

二极管过压失效模式

二极管过压失效模式英文回答:Diode Overvoltage Failure Modes.Diodes are essential components in electronic circuits, and their failure can have significant consequences. Overvoltage is a common cause of diode failure, and it can occur in a variety of ways.One common cause of overvoltage is the application of a voltage that exceeds the diode's reverse breakdown voltage. This can occur during circuit transients, or it can be caused by a fault in the circuit. When the reverse breakdown voltage is exceeded, the diode can enter a state of avalanche breakdown, which can lead to permanent damage.Another cause of overvoltage is the application of a forward voltage that exceeds the diode's forward voltage rating. This can occur during circuit transients, or it canbe caused by a short circuit in the circuit. When the forward voltage rating is exceeded, the diode can enter a state of thermal runaway, which can also lead to permanent damage.In addition to these two main causes of overvoltage, there are a number of other factors that can contribute to diode failure. These include:Temperature: Diodes are more likely to fail at high temperatures. This is because high temperatures can increase the diode's reverse leakage current, which can lead to thermal runaway.Humidity: Diodes that are exposed to high humidity are more likely to fail. This is because humidity can cause the diode's terminals to corrode, which can increase thediode's resistance and lead to thermal runaway.Vibration: Diodes that are exposed to vibration are more likely to fail. This is because vibration can cause the diode's terminals to break, which can lead to an opencircuit.Diode failure can have a number of consequences, including:Circuit malfunction: A failed diode can cause acircuit to malfunction or stop working altogether.Fire: A failed diode can cause a fire if it enters a state of thermal runaway.Electrical shock: A failed diode can cause anelectrical shock if it comes into contact with a person.To prevent diode failure, it is important to use diodes that are rated for the voltage and current requirements of the circuit. It is also important to protect diodes from overvoltage, temperature, humidity, and vibration.中文回答:二极管过压失效模式。

英飞凌IGBT及DIODE简介

英飞凌IGBT及DIODE简介

Vbrces 650V @ 25°C Low Qg Low Coss / Eoss High Softness (H5) Co-pak diode robustness, low Qrr, high dI/dt, dV/dt
•Higher design margin •Cosmic radiation robustness in Solar •Low driving losses „cheap“ driver possible •High efficiency at light load •Low losses in resonant topology smaller resonant tank •low Rgon=Rgoff, Plug&Play replacement (H5) , easy of use. •Low EMI High Reliability in resonant topologies (ZVS/LLC) concerning hard commutation capability of anti-parallel diode
9/16/2013 Copyright © Infineon Technologies 2010. All rights reserved.
Turn-off controllability
Double Pulse characterization Turn-off
0.40
Vce=400V, Tc=25°C, Vge=15V, Ic=20A
25° C
Trade-off previous generation
150° C
TRENCHSTOP™5
TRENCHSTOP™5
At 150°C junction temperature the TRENCHSTOPTM5 offers: The same Vce(sat) value as the TRENCHSTOPTM family

整流二极管使用指南

整流二极管使用指南

Start to pinch off
MOS Depletion Region
N- EPI
Substrate N+
Contact metal
2013/7/31 8
TMBS at High Reverse Bias
Three depletion region layers overlap
Schottky Metal
MOS Depletion Region
Substrate N+
Contact metal
2013/7/31
Pinch-off at adjacent MOS
Electrical Field Distribution of TMBS and Planar Schottky Rectifier
TMBS vs. Planar Schottky
2
Diode Categories
If diodes work over operating cure range, it will change its application characteristic or damaged. Rectifier : automatic switch, used in rectification or isolation Zener : Used in voltage regulation by diode working in avalanche breakdown (continuous breakdown, low power application) TVS : Transient voltage suppressor Transient voltage/energy absorbed by semiconductor chip and lead frame ( discontinuous breakdown, higher power) It has to reduce circuit impedance for the shortest path and get the best protection.

15544+自动化专业英语(习题参考解答)

15544+自动化专业英语(习题参考解答)

自动化专业英语姜书艳主编张昌华徐心皓何芳编著习题参考解答Unit 1A. Basic laws of Electrical Networks[EX.1] Comprehension1. KCL:The algebraic sum of the currents entering any node is zero.KVL:The algebraic sum of the voltage around any closed path is zero.2. Node: A point at which two or more elements have a common connection is calleda node.Branches: a single path in a network composed of one simple element and the node at each end of that element.Path: If no node was encountered more than once, then the set of nodes and elements that we have passed through is defined as a path.Loop: If the node at which we started is the same as the node on which we ended, then the path is, by definition, a closed path or a loop. a path is a particular collection of branches.3. 4, 5, We can form a path but not a loop.4. v R2=32V, V x=6V[EX.2] Translation from English to Chinese1. 如果定义具有最大连接支路数的节点为参考节点,那么得到的方程相对来说比较简单。

Proteus中常用的元器件中英文名称对照

Proteus中常用的元器件中英文名称对照
NPN-PHOTO :感光三极管
OPAMP :运放
OR :或门
PHOTO :感光二极管
PNP :PNP三极管
NPN DAR :NPN三极管
PNP DAR :PNP三极管
POT :滑线变阻器
PELAY-DPDT :双刀双掷继电器
SOURCE VOLTAGE :电压源
SPEAKER :扬声器
SW :开关
SW-DPDY :双刀双掷开关
SW-SPST :单刀单掷开关
SW-PB :按钮
THERMISTOR :电热调节器
TRANS1 :变压器
TRANS2 :可调变压器
ELECTRO :电解电容
FUSE :熔断器
INDUCTOR :电感
INDUCTOR IRON :带铁芯电感
INDUCTOR3 :可调电感
JFET :NN沟道场效应管
JFET :PP沟道场效应管
LAMP :灯泡
LAMP NEDN :起辉器
Optoelectronics :光电子器件
Resistors :电阻
Simulator Primitives :仿真基元
Switches & Relays :开关和继电器
Transistors :三极管
TTL74
74ALS
74AS
74F
74HC
74HCT
74LS
74S series :74系列集成电路
除此之外,还应熟悉常用器件的英文名称,列举如下:
AND :与门
ANTENNA :天线
BATTERY :直流电源(电池)

二极管与门电路详解

二极管与门电路详解

二极管与门电路详解英文回答:Diodes.Diodes are electronic components that allow current to flow in only one direction. They are made of two semiconductor materials, one with a positive charge (the anode) and one with a negative charge (the cathode). When a positive voltage is applied to the anode and a negative voltage is applied to the cathode, the diode allows current to flow. When the voltage is reversed, the diode blocks the current.Diodes are used in a variety of electronic circuits, including power supplies, radios, and computers. They are also used in logic gates, which are used to perform logical operations on binary data.Logic Gates.Logic gates are electronic circuits that performlogical operations on binary data. They are made of transistors, which are electronic components that can act as switches. Logic gates are used in a variety ofelectronic circuits, including computers, calculators, and digital watches.There are several different types of logic gates, including AND gates, OR gates, and NOT gates. AND gates output a 1 only when both inputs are 1. OR gates output a 1 when either input is 1. NOT gates output the opposite of their input.Diode Logic Gates.Diode logic gates are logic gates that are made of diodes. They are simpler than transistor logic gates, but they are also slower and less efficient. Diode logic gates are used in a variety of applications, including automotive electronics and industrial controls.There are several different types of diode logic gates, including AND gates, OR gates, and NOT gates. Diode AND gates are made of two diodes that are connected in series. Diode OR gates are made of two diodes that are connected in parallel. Diode NOT gates are made of a single diode thatis connected to a power supply.中文回答:二极管。

二极管制备工艺流程

二极管制备工艺流程

二极管制备工艺流程Diode manufacturing process plays a crucial role in the electronic industry.二极管制备工艺在电子行业中起着至关重要的作用。

From the initial design to the final product testing, each step requires precision and attention to detail.从最初的设计到最终的产品测试,每个步骤都需要精确和对细节的关注。

The process begins with selecting the appropriate materials for the diode, such as silicon or germanium.制备工艺的第一步是选择适用于二极管的材料,例如硅或锗。

These materials are then processed to form the diode structure, which involves techniques like doping and etching.然后对这些材料进行加工,形成二极管的结构,这涉及掺杂和刻蚀等技术。

Doping is used to introduce impurities into the material to alter its electrical properties, while etching is used to remove excess material and create the desired structure.掺杂是用来向材料中引入杂质以改变其电学性质,而刻蚀则用来去除多余的材料并创造出所需的结构。

After the diode structure is formed, the next step is to assemble the components together.在二极管的结构形成之后,下一个步骤是将各个组件组装在一起。

如何区分二极管和稳压管

如何区分二极管和稳压管

如何区分二极管和稳压管方法一半导体稳压二极管亦纳二极管(Zener Diode)或电压调整二极,简称稳压管。

稳压管和半导体二极管都具有单向导电性质,仅仅靠观察外形,有时很难加以区别。

例如,2CW7的外形很象小功率二极管,而2DW7的外形又与晶体管相似。

但是稳压管和二极管也有重要区别。

第一,二极管一般在正向电压下人作,稳压管则在反向击穿状态下工作,二者用法不同;第二,普通二极管的反向击穿电压一般在40V以上,高的可达几百伏至上千伏,而且在伏安特性曲线反向击穿的一段不陡,即反向击穿电压的范围较大,动态电阻也比较大。

对于稳压管,当反向电压超过其工作电压Vz(亦称齐纳电压或稳定电压)时,反向电流将突然增大,而器件两端的电压基本保持恒定。

对应的反向伏安特性曲线非常陡,动态电阻很小。

稳压管可用作稳压器、电压基准、过压保护、电平转换器等。

本书用Dz符号表示稳压管。

稳压管分低压、高压两种。

低压稳压管的Vz值一般在40V以下,高压稳压管最高可达200V。

过去国产稳压管均采用金属壳封装,不仅体积大,而且价格高。

近年来来全系列玻封存稳压管大量问世,其优点是规格齐全(Vz=2.4~200V)、稳压特性好、体积小巧(采用DO-35封装,管径φ2.0mm,长4mm)、价格低廉。

国产稳压二极管产品的分类见表1。

根据二者反向击穿电压在数值上的差异及稳定性,可以区分标记不清楚的稳压管和普通二极管,电路见图1。

利用兆欧表提供合适的反向击穿电压,将被测管反向击穿。

选择万用表的10VDC档或50VDV档测出反向击穿电压值,数值在40V以上的是二极管,低于40V 的稳压管。

注意,这也有例外情况。

例如2AP21的反向击穿电压低于15V,2AP8的反向击穿电压最小值为20V。

此外,2DW130~2DW143型稳压管的Vz值为50~200V,2CW362~2CW378的Vz值是43~200V(以上均为标称值)。

遇到这类情况也不难区分。

同样都按额定转速摇兆欧表,由于二极管反向击穿区域的动态电阻较大,曲线不陡,因此电压表指针的摆动幅度就比较大。

Diodes

Diodes

DiodesAs with transistors, diodes are fabricated from semi-conducting material. So, the first letter in their identification is A for germanium diode or B for silicon diode. They can be encased in glass, metal or a plastic housing. They have two leads: cathode (k) and an anode (A). The most important property of all diodes is their resistance is very low in one direction and very large in the opposite direction.When a diode is measured with a multimeter and it reads a low value of ohms, this is not really the resistance of the diode. It represents the voltage drop across the junction of the diode. This means a multimeter can only be used to detect if the junction is not damaged. If the reading is low in one direction and very high in the other direction, the diode is operational.When a diode is placed in a circuit and the voltage on the anode is higher than the cathode, it acts like a low value resistor and current will flow.If it is connected in the opposite direction it acts like a large value resistor and current does not flow.In the first case the diode is said to be "forward biased" and in the second case it is "reverse biased."Figure 5.1 shows several different diodes:Fig. 5.1: Several different types of diodesThe diodes above are all single diodes, however 4 diodes are available in a single package. This is called a BRIDGE or BRIDGE RECTIFIER. Examples of a bridge are shown in the diagram below:You must be able to identify each of the 4 leads on a bridge so that it can be inserted into a circuit around the correct way. The surface-mount device above is identified by a cut @ 45° along one side. The leaded bridge has one leg longer than the others and the top is marked with AC marks and "+." The high-current bridge has a corner cut off and the other surface-mount device has a cut or notch at one end.These devices are added to a circuit as shown in the next diagram:The 4 diodes face the same direction and this means a single diode can be shown on the circuit diagram:Symbols in 5.2 show a number of diodes. There are a number of specially-designed diodes: for high current, high-speed, low voltage-drop, light-detection, and varying capacitance as the voltage is altered. Most diodes are made from silicon as it will withstand high temperature, however germanium is used if a low voltage-drop is required. There is also a light emitting diode called a LED, but this is a completely different type of diode.Fig. 5.2: Diode symbols: a - standard diode, b - LED,c, d - Zener, e - photo, f,g - tunnel, h - Schottky, i - breakdown,j - capacitativeLEDs (Light Emitting Diodes) are constructed from a crystalline substance that emits light when a current flows through it. Depending on the crystalline material: red, yellow, green, blue or orange light is produced. The photo below shows some of the colours hat can be produced by LEDs:It is not possible to produce white light from any of these materials, so a triad of red, blue and green is placed inside a case and they are all illuminated at the same time to produce white light. Recently, while light has been produced from a LED by a very complex and interesting process that can be found onWikipedia: /wiki/LEDLEDs have a cathode and anode lead and must be connected to DC around the correct way. The cathode lead is identified on the body by a flat-spot on the side of the LED. The cathode lead is the shorter lead.One of the most important things to remember about a LED is the characteristic voltage that appears across it when connected to a voltage. This does not change with brightness and cannot be altered.For a red LED, this voltage is 1.7v and if you supply it with more than this voltage, it will be damaged.The easy solution is to place a resistor on one lead as shown in the diagram below:The LED will allow the exact voltage to appear across it and the brightness will depend on the value of the resistor.Zener diodes (5.2c and 5.2d) are designed to stabilize a voltage. Diodes marked as ZPD5.6V or ZPY15V have operating voltages of 5.6V and 15V.Photo diodes (5.2e) are constructed in a way that they allow light to fall on the P-N connection. When there is no light, a photo diode acts as a regular diode. It has high resistance in one direction, and low resistance in opposite direction. When there is light, both resistances are low. Photo diodes and LEDs are the main items in an optocoupler (to be discussed in more detail in chapter 9).Tunnel diodes (5.2f and 5.2g) are commonly used in oscillators for very high frequencies.Schottky diodes (5.2h) are used in high frequency circuits and for its low voltage drop in the forward direction.Breakdown diodes (5.2i) are actually Zener diodes. They are used in various devices for protection and voltage regulation. It passes current only when voltage rises above a pre-defined value.A Varicap diode (5.2j) is used instead of a variable capacitor in high frequency circuits. When the voltage across it is changed, the capacitance between cathode and anode is changed. This diode is commonly used in radio receivers, transceivers and oscillators.The cathode of a low power diode is marked with a ring painted on the case, but it is worth noting that some manufacturers label the anode this way, so it is best to test it with a multimeter.Power diodes are marked with a symbol engraved on the housing. If a diode is housed in a metal package, the case is generally the cathode and anode is the lead coming from the housing.5.1 Diode identificationEuropean diodes are marked using two or three letters and a number. The first letter is used to identify the material used in manufacturing the component (A - germanium, B - silicon), or, in case of letter Z, a Zener diode.The second and third letters specify the type and usage of the diode. Some of the varities are:A - low power diode, like the AA111, AA113, AA121, etc. - they are used in the detector of a radio receiver; BA124, BA125 : varicap diodes used instead of variable capacitors in receiving devices, oscillators, etc., BAY80, BAY93, etc. - switching diodes used in devices using logic circuits. BA157, BA158, etc. - these are switching diodes with short recovery time.B - two capacitive (varicap) diodes in the same housing, like BB104, BB105, etc.Y - regulation diodes, like BY240, BY243, BY244, etc. - these regulation diodes comein a plastic packaging and operate on a maximum current of 0.8A. If there is another Y, the diode is intended for higher current. For example, BYY44 is a diode whose absolute maximum current rating is 1A. When Y is the second letter in a Zener diode mark (ZY10, ZY30, etc.) it means it is intended for higher current.G, G, PD - different tolerance marks for Zener diodes. Some of these are ZF12 (5% tolerance), ZG18 (10% tolerance), ZPD9.1 (5% tolerance).The third letter is used to specify a property (high current, for example). American markings begin with 1N followed by a number, 1N4001, for example (regulating diode), 1N4449 (switching diode), etc.Japanese style is similar to American, the main difference is that instead of N there is S, 1S241 being one of them.5.2 Diode characteristicsThe most important characteristics when using power diodes is the maximum current in the forward direction (IFmax), and maximum voltage in the reverse direction (URmax).The important characteristics for a Zener diode are Zener voltage (UZ), Zener current (IZ) and maximum dissipation power (PD).When working with capacitive diodes it is important to know their maximum and minimum capacitance, as well as values of DC voltage during which these capacitances occur.With LEDs it is important to know the maximum value of current it is capable of passing. The natural characteristic voltage across a LED depends on the colour and starts at 1.7V for red to more than 2.4v for green and blue.Current starts at 1mA for a very small glow and goes to about 40mA. High brightness LEDs and "power LEDs" require up to 1 amp and more. You must know the exact current required by the LED you are using as the wrong dropper resistor will allow too much current to flow and the LED will be damaged instantly.The value of this resistors will be covered in another chapter.Beside universal transistors TUN and TUP (mentioned in Chapter 4.4), there are universal diodes as well. They are marked with DUS (for universal silicon diode) and DUG (for germanium) on circuit diagrams.DUS = Diode Universal Silicon DUG = Diode Universal Germanium 5.3 Practical examplesThe diagram of a power supply in figure (3.8) uses several diodes. The first four are in a single package, identified by B40C1500. This is a bridge rectifier.The LED in the circuit indicates the transformer is working. Resistor R1 is used to limit the current through the LED and the brightness of the LED indicates the approximateDiodes marked 1N4002 protect the integrated circuit.Figure 5.3 below shows some other examples of diodes. The life of a globe can be increased by adding a diode as shown in 5.3a. By simply connecting it in series, the current passing through the globe is halved and it lasts a lot longer. However the brightness is reduced and the light becomes yellow. The Diode should have a reverse voltage of over 400V, and a current higher than the globe. A 1N4004 or BY244 is suitable.A very simple DC voltage stabilizer for low currents can be made using 5.3c as a reference.Fig. 5.3: a - using a diode to prolong the light bulb's life span, b - stair-light LEDindicator,c - voltage stabilizer,d - voltage rise indicator, e - rain noise synthesizer,f -backup supplyUnstabilized voltage is marked "U", and stabilized with "UST." Voltage on the Zener diode is equal to UST, so if we want to achieve a stabilized 9V, we would use a ZPD9.1 diode. Although this stabilizer has limited use it is the basis of all designs found in powerWe can also devise a voltage overload detector as sown in figure 5.3d. A LED indicates when a voltage is over a predefined value. When the voltage is lower than the operating voltage of the Zener, the zener acts as a high value resistor, so DC voltage on the base of the transistor is very low, and the transistor does not "turn on." When the voltage rises to equal the Zener voltage, its resistance is lowered, and transistor receives current on its base and it turns on to illuminate the LED. This example uses a 6V Zener diode, which means that the LED is illuminated when the voltage reaches that value. For other voltage values, different Zener diodes should be used. Brightness and the exact moment of illuminating the LED can be set with the value of Rx.To modify this circuit so that it signals when a voltage drops below some predefined level, the Zener diode and Rx are swapped. For example, by using a 12V Zener diode, we can make a car battery level indicator. So, when the voltage drops below 12V, the battery is ready for recharge.Figure 5.3e shows a noise-producing circuit, which produces a rain-like sound. DC current flowing through diode AA121 isn't absolutely constant and this creates the noise which is amplified by the transistor (any NPN transistor) and passed to a filter (resistor-capacitor circuit with values 33nF and 100k).Figure 5.3f shows a battery back-up circuit. When the "supply" fails, the battery takes over.。

稳压二极管(Zenerdiode)

稳压二极管(Zenerdiode)

稳压二极管(Zener diode)Zener diode (also known as zener diode) is a silicon material surface contact type crystal diode, referred to as the regulator. This diode is a semiconductor device with a high resistance until the critical reverse breakdown voltage is applied. The reverse breakdown voltage regulator tube, in a certain range of the current (or power loss in certain range), the terminal voltage is almost constant, showing steady voltage characteristic, so it is widely used in power supply and limiting circuit. Zener diodes are classified according to the breakdown voltage of the file, because of this characteristic, the regulator is mainly as a regulator or a voltage reference element. The I-V curves shown in Figure 1, the zener diode can connected in series for use in high voltage, the series can obtain more stable voltage.See the wonderful AtlasCatalogMain parameter stable voltage VzDissipation power PZSteady current IZDynamic resistance rZSteady voltage temperature coefficientParameter meaning Vz-- stable voltageIz - steady currentRz - dynamic resistancePz - rated power dissipationCtv - voltage temperature coefficient IR reverse leakage currentWorking principleIdentification method 1Method twoVolt ampere characteristicsMain categoriesDiode differenceProduct selectionDistinguishProduct applicationChoiceMatters needing attentionExpand the main parameter stable voltage Vz Dissipation power PZSteady current IZDynamic resistance rZSteady voltage temperature coefficient Parameter meaning Vz-- stable voltageIz - steady currentRz - dynamic resistancePz - rated power dissipationCtv - voltage temperature coefficientIR reverse leakage currentWorking principleIdentification method 1Method twoVolt ampere characteristicsMain categoriesDiode differenceProduct selectionDistinguishProduct applicationChoiceMatters needing attentionEdit the main parameters of this segment, the main parameters of the regulator:Stable voltage VzThe steady voltage is the voltage at the two ends of the diode when the diode is in normal operation. This value varies slightly with the operating current and temperatureEven if the same type of Zener diode, the stability voltage value is also a certain dispersion, for example, 2CW14 silicon zener diode stable voltage is 6 ~ 7.5V.Dissipation power PZReverse current through the zener diode PN junction, to producea certain power loss, PN junction temperature will rise. According to the allowable PN junction operating temperature, the dissipation power of the pipe is determined. Usually a small power tube is about a few hundred watts to a few watts. Maximum dissipation power PZM: the maximum power loss of the regulator depends on the area of the PN junction and the heat dissipation conditions. In reverse operation, the power loss of PN junction is PZ=VZ*IZ, and PZM and VZ can determine IZmax.Steady current IZThe minimum stable current Izmin, stable current Izmax stable current: working voltage is equal to the reverse current voltage stability; minimum stable current: minimum reverse current zener diode working in stable voltage when required; maximum stable current: maximum zener diode reverse current through the.Dynamic resistance rZThe concept is the same as the general diode's dynamic resistance, but the dynamic resistance of the zener diode is derived from its reverse characteristics. The smaller the rZ is, the more remarkable the breakdown characteristics of the zener tube are. Rz= Delta VZ/ Delta IZSteady voltage temperature coefficientThe change of temperature will make VZ change. In the regulator tube, when |VZ|>7V, VZ has positive temperature coefficient, reverse breakdown is avalanche breakdown. When |VZ|<4V is used,VZ has negative temperature coefficient, and reverse breakdown is zener breakdown. When 4V<|VZ|<7V, the regulator can obtain near zero temperature coefficients. Such a zener diode can be used as a standard regulator tube. Edit this paragraph parameter meaning Vz-- stable voltageRefers to the voltage regulator through the rated current generated at both ends of the stable voltage value. This value varies slightly with the operating current and temperature. Due to the difference in manufacturing process, the same model regulator tube voltage regulator is not exactly the same. For example, the 2CW51 type regulator Vzmin is 3.0V, and Vzmax is 3.6V.Iz - steady currentRefers to the current value of the tube when a stable voltage is produced by the regulator. Below this value, although the regulator is not unable to regulate voltage, but the effect of voltage regulation will become worse; high voltage regulatorAt this value, as long as not exceeding the rated power loss, is also allowed, and the performance of voltage regulation will be better, but to consume more electricity. The maximum stable operating current depends on the maximum dissipation power, i.e., Pzmax=Vz*Izmax. And Izmin corresponds to Vzmin.Rz - dynamic resistanceThe ratio of the voltage across the regulator tube to thecurrent. The ratio varies with the operating current, and the larger the operating current is, the smaller the dynamic resistance is. For example, when the operating current of the 2CW7C regulator is 5mA, the Rz is 18; when the operating current is 10mA, the Rz is 8; for the 20mA, the Rz is 2. Rz=DVz/DIz,The smaller the Rz is, the more remarkable the breakdown characteristics of the zener tube are.Pz - rated power dissipationDetermined by the allowable temperature rise of the chip, the value is the product of the stable voltage Vz and the maximum current Izm allowed. For example, the 2CW51 regulator tube Vz is 3V, the Izm regulator tubeFor 20mA, the Pz of the tube is 60mW.Ctv - voltage temperature coefficientIs a parameter that indicates the influence of temperature on the steady voltage. For example, the 2CW58 regulator tube Ctv is +0.07%/ degrees C, that is, the temperature increased by 1 degrees per C, its voltage regulator value will rise by 0.07%.IR reverse leakage currentA leakage current produced by a regulated diode at a specified reverse voltage. For example, the 2CW58 regulator tube is VR=1V, IR=0.1uA; at VR=6V, IR=10uA. Edit this paragraph working principle, the regulator tube is also a kind of crystal diode,it is the use of PN junction breakdown zone with stable voltage characteristics to work. The regulator tube is widely used in voltage stabilizing equipment and some electronic circuits. This type of diode is called a voltage regulator to distinguish between diodes used in rectification, detection, and other unidirectional conducting situations. Voltage regulator diode is characterized by breakdown, the voltage at its ends remain unchanged. Thus, when the voltage regulator is connected to the circuit, the voltage at the two ends of the circuit will remain the same if the voltage of the circuit changes due to the fluctuation of the supply voltage or other causes. As shown in the picture, the volt ampere characteristics and symbols of the regulator tube. After the reverse breakdown of the regulator, the current changes in a large range, but the voltage at the two ends of the regulator is very small. With this characteristic, the regulator can play a stabilizing role in the circuit. Because of this characteristic,The regulator is mainly used as a voltage regulator or a voltage reference element. The volt ampere characteristic is that the diode can be connected in series so that it can be used at higher voltage, and more stable voltage can be obtained by series connection. The three terminal regulator belongs to the integrated circuit strictly. After comparing the output voltage to the internal reference voltage, the drive adjustment tube is adjusted to a steady value. Individual components can be used to measure the resistance between the feet to determine whether the damage is rough, preferably measured in the access circuit. Voltage adjustment and ripple indicators are only tested by professional instruments. Under amateur conditions, the oscilloscope can also be qualitatively checked. A voltagestabilizing diode is also a crystal diode, which uses the characteristics of stable voltage in the breakdown area of PN junction. The regulator tube is widely used in voltage stabilizing equipment and some electronic circuits. We refer to this type of diode as a voltage regulator to distinguish between diodes used in rectification, detection, and other unidirectional electrical conduction. (1) stable voltage Uz Uz is the breakdown voltage of PN junction, which varies slightly with the operating current and temperature. For the same type of regulator, the voltage regulator has a certain discreteness.(2) the reference current value of the stable current Iz regulator. It usually has a certain range, that is, Izmin - Izmax. (3) the dynamic resistance RZ is the ratio of the voltage change at the two ends of the regulator tube to the current, as shown in the figure above, i.e., this value varies with the operating current. Usually, the higher the operating current, the smaller the dynamic resistance, the better the regulator performance.(4) voltage temperature coefficient, which is used to show the coefficient of the influence of temperature change on the steady voltage. Different types of regulators have different stable voltage temperature coefficients, and there are positive and negative points. The 4V value is lower than the voltage regulator tube, stable temperature coefficient voltage is negative; voltage higher than 6V zener diode, the temperature coefficient of the voltage stability is positive; between 4V and 6V, can be positive or negative. In a situation where high demand is required, two tubes with opposite temperature coefficients can be compensated in series (e.g., 2DW7). (5) before the rated power consumption Pz, it has beenpointed out that the greater the operating current, the smaller the dynamic resistance, the better the voltage regulator performance, but the maximum operating current is limited by the rated power consumption Pz, more than Pz will make the regulator damaged. Regulator tubeEdit this paragraph identification method oneZener diode in the circuit commonly used "ZD" plus digital representation, such as: ZD5 means that the number is 5 of the regulator. 1, zener diode voltage regulator principle: zener diode is characterized by breakdown, the two ends of the voltage remains unchanged. Regulator tubeThus, when the voltage regulator is connected to the circuit, the voltage at the two ends of the circuit will remain the same if the voltage of the circuit changes due to the fluctuation of the supply voltage or other causes. 2, fault characteristics: voltage regulator diode fault is mainly manifested in open circuit, short circuit and voltage regulator instability. Of these 3 faults, the former fault shows an increase in the supply voltage, and the latter 2 appear as low voltage to zero volts or unstable output.The other test is a 2CW136 type regulator hand is basically stable, refers to the position of 115V (100 ~ 2DW136 voltage range given only in the manual 120V, but specific to a zener diode, the voltage is a determined value)Method twoThe voltage regulator and the diode can also be distinguished by the resistance register of the multimeter. The concrete method is that the positive and negative resistance of the tube to be measured is determined by measuring the positive and negative resistance in the R * 1K file at first. Then the meter dial in R * 10K file, as shown in the figure, the black probe is connected to the anode, the red pen is connected with the positive pole, from table 9 ~ 15V laminated battery reverse voltage. Among them, the resistance reading is smaller than the zener diode, the resistor is infinite diode. Note: (1) this method can only measure the reverse strike voltage of the voltage regulator lower than the R * 10K battery voltage. Model comparison table of common regulator:。

AD元器件英文对照

AD元器件英文对照

1.电阻固定电阻:RES半导体电阻:RESSEMT电位计;POT变电阻;RV AR可调电阻;res12.电容定值无极性电容;CAP定值有极性电容;CAP半导体电容:CAPSEMI可调电容:CAPV AR3.电感:INDUCTOR4.二极管:DIODE.LIB发光二极管:LED5.三极管:NPN16.结型场效应管:JFET.lib7.MOS场效应管8.MES场效应管9.继电器:PELAY. LIB10.灯泡:LAMP 11.运放:OPAMP12.数码管:DPY_7-SEG_DP (MISCELLANEOUS DEVICES.LIB)13.开关;sw_pb原理图常用库文件:Miscellaneous Devices.ddbDallas Microprocessor.ddbIntel Databooks.ddbProtel DOS Schematic Libraries.ddbPCB元件常用库:Advpcb.ddbGeneral IC.ddbMiscellaneous.ddb部分分立元件库元件名称及中英对照AND 与门初学protel DXP 碰到最多的问题就是:不知道元件放在哪个库中。

这里我收集了DXP2004常用元件库下常见的元件。

使用时,只需在libary中选择相应的元件库后,输入英文的前几个字母就可看到相应的元件了。

通过添加通配符*,可以扩大选择范围。

下面这些库元件都是DXP 2004自带的不用下载。

########### DXP2004下Miscellaneous Devices.Intlib元件库中常用元件有:电阻系列〔res*〕排组〔res pack*〕电感〔inductor*〕电容〔cap*,capacitor*〕二极管系列〔diode*,d*〕三极管系列〔npn*,pnp*,mos*,MOSFET*,MESFET*,jfet*,IGBT*〕运算放大器系列〔op*〕继电器〔relay*〕8位数码显示管〔dpy*〕电桥〔bri*bridge〕光电耦合器( opto* ,optoisolator )光电二极管、三极管〔photo*〕模数转换、数模转换器〔adc-8,dac-8〕晶振〔xtal〕电源〔battery〕喇叭〔speaker〕麦克风〔mic*〕小灯泡〔lamp*〕响铃〔bell〕天线〔antenna〕保险丝〔fuse*〕开关系列〔sw*〕跳线〔jumper*〕变压器系列〔trans*〕????〔tube*〕〔scr〕〔neon〕〔buzzer〕〔coax〕晶振〔crystal oscillator〕的元件库名称是Miscellaneous Devices.Intlib, 在search 栏中输入*soc 即可。

  1. 1、下载文档前请自行甄别文档内容的完整性,平台不提供额外的编辑、内容补充、找答案等附加服务。
  2. 2、"仅部分预览"的文档,不可在线预览部分如存在完整性等问题,可反馈申请退款(可完整预览的文档不适用该条件!)。
  3. 3、如文档侵犯您的权益,请联系客服反馈,我们会尽快为您处理(人工客服工作时间:9:00-18:30)。

I. Diode and Diode Application1.Diodes2.Rectification3.Power supply filter4.Applications of diodes︒Signal rectifier︒Diode gate︒Diode clamps︒Limiter1.DiodesSome elements are linear (resistors, capacitors, inductors), which means that doubling the applied signal (let us say a voltage) produces a doubling of the response (let us say a current). They are also passive– they do not have built-in source of power. They are two-terminal devices, (which is self-explanatory).Diode is also two-terminal, passive but non-linear a device. Figure 1 shows the diode.Fig.1. Diode. Fig.2. Diode voltage-current curve, U-I curve.In Fig. 2 there is U-I (voltage-current) curve (characteristic). The diode arrow, anode terminal, shows the direction of forward current flow. If the diode is in a circuit in which a current of 10mA=10*10-3A is flowing from anode to cathode, then the anode is approximately0.5 volt more positive than cathode. We call it the forward voltage drop. The reverse current is measured in nanoampers and 1nA=1*10-9A. It is so small in comparison to mA, that can be neglected until we reach the reverse breakdown voltage. Typically it is approximately 75V and normally we never subject a diode to voltage large enough to cause reverse breakdown.Similarly, the forward voltage drop, which is about 0.5 or 0.8 V, is of little concern. For these reasons we treat the diode as a good approximation of an ideal one-way conductor.Commercially available diodes are described also by other important characteristics, e.g.: maximum forward current, capacitance (measured in pF), leaking current, reverse recovery time (measured in nanoseconds, 0-2-4-5000).2.RectificationA rectifier changes ac (alternating current) to dc (direct current). This is the most important application of diodes. Diodes are sometimes called rectifiers.The basic circuit is shown in Fig. 3.Fig.3. Half-wave rectifier.The ac represents a source of ac voltage. It can be a transformer or just ac sine-wave power line. For sine-wave input, of amplitude much larger than forward voltage drop, the output will look like it is shown in Fig. 4.Fig.4. Voltage across R load in Fig.3.The process and the circuit we call a half-wave rectifier, because only half of the input waveform is used.In Fig. 5 is shown a full-wave rectifier and Fig. 6 shows the voltage across the load. The small gaps across zero voltage occur because of the forward voltage drop.Fig.5. Full-wave bridge rectifier.Fig.6. Voltage across R load in Fig.5.3. Power supply filteringThe rectified wave from Fig.6 is not good for application: it is dc only in the sense that it does not change polarity. But it does not have constant value and has plenty of ripples i.e. small waves or undulations (wave like forms). It has to be smoothed out in order to obtained authentic direct current. This can be done by means of a low-pass filter, which is shown in Fig. 7.Fig.7. Full-wave bridge with RC filter.The full-wave bridge diodes prevent flow of current back out of capacitor. The capacitor is an energy storage element. The energy stored in a capacitor is 221CU E =. For C in F (farads) and U in V (Volts), E comes out in J (jouls) and J=Watt/sek. The capacitor value is chosen so that f /R load 1>>, where f is the ripple frequency. For power line sine wave it is 2*50Hz=100Hz. It allows to ensure small ripples, by making the time constant for discharge much longer than the time between recharging (the capacitor is charging very quickly, while discharging is very slow).It is quite easy to calculate the approximate ripple voltage (see Fig. 8). Let us assume that the load current stays constant (it will, for small ripples). The load causes the capacitor to discharge somewhat between cycles. The capacitor will loose some voltage, let us say U ∆. In this case, we have:t CI U ∆=∆, (from dt dU C I =)Fig.8. Power-supply ripple calculation.Instead of t ∆ we use f /1 or f /21 respectively for half-wave rectification and for full-wave rectification. Finally we obtain approximate ripple voltage:︒ for halve-wave fC I U load =∆, ︒ for full-wave fCI U load 2=∆. If one wanted to do exact calculation (with no approximation), one would use the exact exponential formula (see lecture Capacitors, RC circuits ). Sometimes it may be necessary.A dc power supply using the bridge circuit looks (in the USA) as shown in Fig.9.Fig.9. Bridge rectifier circuit. The curved electrode indicates a polarized capacitor, which must not be allowed the opposite polarity.4. Applications of diodes︒ Signal rectifierIf the input is not a sine wave, we usually do not think of it as a rectification in the sense as it was for power supply. For instance, we might want to have a series of pulses corresponding to the rising edge of a square wave (see Fig. 10, left hand side and right hand side of the capacitor C). While both, the rising and the falling, pulses are in the output after differentiation performed by CR circuit. The simplest way is to rectify the differentiated wave.Fig.10. A series of pulses' rectifier.We should remember about forward drop voltage of the diode: This circuit gives no output for signal for input smaller then, forward drop voltage, let us say 0.5 V pp (peak to peak). If this is a problem, there are various tricks that help to combat this limitation. For instance:e Schottky diodes with smaller forward drop voltage (approximately 0.2V),e so called circuit solution, which means modifying the circuit structure andcompensating the drop,e matched-pair compensation, use transistors, FETs.︒Diode gatesAnother application of diode is to pass the higher of two voltages without affecting the lower.A good example is battery backup, a method of keeping s device running (for instance a precision electronic clock) in case of power failure. Figure 11 shows a circuit that does the job.Fig.11. Diode OR gate, battery backup.[OR gate: The output of OR gate is HIGH if either input (or both) is HIGH. In general, gates can have any number of inputs. The output is LOW only if all inputs are LOW].1.The battery does nothing until the power fails.2.Then the battery takes over the control, without interruption.︒Diode clamps (stabilizatory poziomu)Sometimes it is necessary to limit the range of signal (for instance not to exceed certain voltage limit and not to destroy a device). The circuit in Fig. 12 will accomplish this.Fig.12. Diode voltage clamp.The diode prevents the output from exceeding ≅5.6V, with no effect on voltages smaller than this, including negative voltages. The only limitation is that the input must not be so negative that the reverse breakdown voltage is exceeded. Diode clamps are the standard equipment on all inputs in the CMOS family of digital logic (Complementary Metal Oxide Semiconductor). Without them, the delicate input circuits are easily destroyed by static electricity.︒LimiterThe circuit in Fig.13 limits the output swing to one diode drop, roughly 0.6V.Fig.13. Diode limiter.It might seem very small, but if the next device is an amplifier with large voltage amplification, its input has to be always near zero voltage. Otherwise the output is in state of saturation. For instance we have an op amp with a gain of 1000. The amplifier operates with supply voltage ±15V. Sometimes it can be ±12V or ±18V or something in between. It will never give output voltage bigger than the supply voltage, i.e. ±15V. It means that the input signal ±15mV (±15V/1000) or bigger will saturate the output. This particular amplifier gives the output proportional to the input (proportionality factor is 1000) only for input signals from the interval (-15mV,+15mV).This diode limiter is often used as input protection for high-gain amplifiers.。

相关文档
最新文档