Consider the following transducers: 1. LVDT 2. Piezoelectric 3. Thermocouple 4. Photovoltaic cell 5. Strain gauge Which of these are active transducers?

Option 1 : 2, 3 and 4

Thermocouple and Thermistor are examples of the active transducer and passive transducer respectively.

Transducer:

A transducer is an electronic device that converts energy from one form to another. Common examples include microphones, loudspeakers, thermometers, i.e.

Analog transducers:

• These transducers convert the input quantity into an analog output which is a continuous function of time
• Thus, a strain gauge, an L.V.D.T., a thermocouple, or a thermistor may be called Analog Transducers as they give an output that is a continuous function of time

Digital Transducers:

• These transducers convert the input quantity into an electrical output which is in the form of pulses and its, output is represented by 0 and 1