Electrical Engineering ⇒ Topic : Transducers and Their Applications

TRANSDUCERS AND THEIR APPLICATIONS

A general arrangement of most measuring systems consists of three stages which are shown in Figure (a).

An input device to sense the measurand  - a sensor detector to give proportional output.

A signal processor or conditioner. This may consist of amplification, filtering unwanted signals and making it suitable for the recording device.

An output device for read out.

                                                           figure (a)

How we are concerned with the first stage of conversion of a particular physical quantity  into equivalent electrical signals. This type of device is known as transducer.

There are two types of transducers: (i) Passive or modulating type and (ii) Self-generating.

In the passive type, the non-electrical quantity changes resistance, inductance or capacitance (R, L, or C) to which an external supply is applied.

In generating type, the non-electrical quantity generates a voltage directly by piezoelectric effect and thermo-e.m.f.

The choice of a transducer depends on a number of factors such as the physical quantity that is to be transformed, ambience, and environmental conditions. It finds application in the measurement of:

• Displacement
• Temperature

Transducers:-  transducer is a device which converts the energy from one form to another.Most of the transducers either convert electrical energy into mechanical displacement and/or convert some non-electrical physical quantity (i .e . force, sound, temperature).