Page 876 - Basic Electrical Engineering

Figure 12.1 Illustration of the principle of a passive transducer

Digital transducers convert the input physical phenomenon into an

electrical output in the form of a train of digital pulses using a binary system
of notation. Since transducers are often required to communicate with

computers, transducers with digital output are required. In the case of analog
transducers, conversion of analog signals to digital signals will be required to
be interfaced with a computer system.

Since digital transducers are few, we therefore mostly use analog
transducers to produce a voltage signal and an electronic A to D (Analog to

Digital) converter to get the digital data in the binary form, i.e., 0 and 1.

12.3 CHARACTERISTICS OF A TRANSDUCER

Transducers are used in the measurement of system parameters as an input-
sensing element. The received signal requires processing. The signal
processing involves amplification of the signal, its conversion from analog to

digital form, its transmission, its display, its recording, etc.
Since transducers generate the basic measurement signal, they must

possess certain desirable characteristics which are mentioned below:

i. Sensitivity: It is defined as the output per unit input of the quantity being measured. For
example, the output of a thermocouple used as a transducer is expressed as EMF induced per