电子专业英语试题(A)

专业英语试题------翻译资料A

1.

The number system with which we are most familiar is the base 10, or decimal system. Recent technological developments have created the need for other number systems. The electronic computer, for example, required the development of systems that were easily adapted to electronic processes. These number systems were binary (base 2), octal (base 8), and hexadecimal (base 16). The binary system is the primary language of the computer and the octal and hexadecimal systems are usually used for communication with the computer and for the storage of information within the computer. Since computers can only process binary numbers or numbers coded in other systems such as octal and hexadecimal, the decimal system must be converted to one of the other systems before it can be processed by the computer. When the computer finishes its operations on the information, the output is printed or displayed in number system other than decimal, and this too must be converted, this time back to the decimal system.

2.

The edge triggered RS flip flop actually consists of two identical RS latch circuits.The inverter connected between the two CLK inputs ensures that the two sections will be enabled during opposite half cycles of the clock signal. This is the key to the operation of this circuit. Therefore，the

Q and _Q outputs can only change state when the CLK signal falls from a logic 1 to logic 0. This is known as the falling edge of the CLK signal; hence the designation edge triggered flip flop.

3. The FET shown is an N-channel FET, which is composed of two N-type regions separated by a P-type substrate. When a voltage is applied to the insulated gate terminal, a current is enabled to flow from the drain to the source. It is called N-channel, because the gate voltage induces an N-channel within the substrate, enabling current to flow between the N-regions.

4.

An inductor is an electrical device which can temporarily store electromagnetic energy in the field. The inductor is a coil of wire that may have an air core of an iron core to increase its inductance. A powered iron core in the shape of a cylinder may be adjusted in and out of the core. An inductor tends to oppose a change in electrical current, it has no resistance to DC current but has an AC resistance to AC frequency and is given by the formula X L=2πfL, with units of ohms. Inductors are used for filtering AC current. It is electrically opposite to the capacitor. Its value is expressed in Henry (more commonly milliHenries). There are two major types of inductors, air core and iron core.