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Transducers

Transducers

Classification of Transducers

Self-Generating Transducers – Active Transducers

SELECTING A TRANSDUCER

Resistive Transducers

Strain gauges

Unbonded Metal Strain Gauge

Bonded Metal Foil Strain Gauges

Evaporation Deposited Thin Metal Strain Gauges

Semiconductor Strain Gauges

Rosettes

LVDT

Resistive Transducers for Pressure Measurement

Inductive Transducers for Pressure Measurement

Measurement of Temperature

RTD - resistance temperature detector

Thermistors

Thermocouples

Photo-conductive and photo-voltaic cells

Transducers

Nearly all engineering applications require some form of measuring, controlling, calculating,
communicating and recording of data. These operations, grouped or isolated, are inherent in
measurement instrumentation. If the equipment is to be used for the quantitative analysis of an analogue signal, i.e., a naturally occurring signal, the following must be taken into consideration:

The analogue signal to be measured may be temperature, pressure, humidity, velocity, flow rate, linear motion, position, amongst others. This signal must be converted into an analogue electrical signal, typically voltage or current, and then into a digital form that can be processed by an electronic circuit. The first task (see Fig. 1) requires sensors to convert the physical quantities into electrical signals. Generally, the broad definition of a sensors/ transducers includes devices which convert physical quantities (mechanical force) into analogue electrical signal (in the range of millivolts or milliamps).