Formation of Temperature Controller using Thermistor in Differential Instrumentation Amplifier.

What kind of configuration will be formed/set up by replacing a meter with relay along with the usage of a thermistor in the transducer bridge circuit of a differential instrumentation amplifier?

a. Temperature Indicator
b. Temperature Controller
c. Light-intensity meter
d. Thermal Conductivity meter

Correct Answer : b. Temperature Controller

Explanation :

Temperature control circuit can be built up by using a thermistor in bridge circuit along with the replacement of a meter by a relay in the structural configuration of differential instrumentation amplifier. It is possible to control the current in the heat-generating circuit with an assistance of relay driven by the temperature controller itself. Temperature indicator is also constructed using thermistor as a transducer with the only difference that output meter is calibrated in degree Celsius or Fahrenheit. Despite bridge circuits, light-intensity meter can be built-up by using a photocell as a transducer while two thermistors are adjacently connected in thermal conductivity meter circuits.