中英文翻译传感器重点

传感器的基础知识

Basic knowledge of transducers

A transducer is a device which converts the quantity being measured into an optical,mechanical, or-more commonly-electrical signal. The energy-conversion process that takesplace is referred to as transduction. Transducers are classified according to the transduction principle involved and the form of themeasured. Thus a resistance transducer for measuring displacement is classified as aresistance displacement transducer. Other classification examples are pressure bellows, force diaphragm, pressure flapper-nozzle, and so on.

1. Transducer Elements

Although there are exception ,most transducers consist of a sensing element and a conversionor control element. For example, diaphragms,bellows,strain tubes and rings, bourdon tubes,and cantilevers are sensing elements which respond to changes in pressure or force and convert these physical quantities into a displacement. This displacement may then be used tochange an electrical parameter such as voltage, resistance, capacitance, or inductance. Such combination of mechanical and electrical elements form electromechanical transducing devices or transducers. Similar combination can be made for other energy input such as thermal. Photo, magnetic and chemical,giving thermoelectric, photoelectric,electromaanetic,and electrochemical respectively.

2. Transducer Sensitivity

The relationship between the measured and the transducer output signal is usually obtained bycalibration tests and is referred to as the transducer sensitivity Kl=output-signal increment /measured increment. In practice, the transducer sensitivity is usually known, and, bymeasuring the output signal, the input quantity is determined from input = output-signal increment / Kl.

3. Characteristics of an Ideal Transducer

The high transducer should exhibit the following characteristics.

a high fidelity-the transducer output waveform shape be a faithful

reproduction of the measured; there should be minimum distortion. b There should be minimum interference with the quantity being measured; the presence of the transducer should not alter the measured in any way.

c Size. The transducer must be capable of being place

d exactly wher

e it is needed.

d Ther

e should be a linear relationship between the measured and the transducer signal.

e The transducer should have minimum sensitivity to external effects, pressure transducers,for example,are often subjected to external effects such vibration and temperature

fThe natural frequency of the transducer should be well separated from the frequency and harmonics of the measurand.

4. Electrical Transducers

Electrical transducers exhibit many of the ideal characteristics. In addition they offer high sensitivity as well as promoting the possible of remote indication or mesdurement.Electrical transducers can be divided into two distinct groups:

a variable-control-parameter types,which include:

i resistance

ii capacitance