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Transducers

Classification of Transducers

SELECTING A TRANSDUCER

Strain gauges

Gauge factor

Types of Strain Gauges

Bonded Metal Foil Strain Gauges

Semiconductor Strain Gauges

Rosettes

LVDT

Linear Variable Differential Transformer – LVDT Transducer

Applications of LVDT

Measurement of Temperature

RTD - resistance temperature detector

Thermistors

Thermistors for Measurement of Temperature

Thermocouples

Photo-conductive and photo-voltaic cells

Photoconductive Cells

Photovoltaic 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).