Automobile Electrical and Electronic Systems, 5th Edition

Electrical and electronic principles

42

Figure 1.50 Thermocouple principle and circuits

Figure 1.51 Inductive sensor

The lower gure shows a practical circuit in which, if the connections to the

meter are at the same temperature, the two voltages produced at these

junctions will cancel out.

Cold junction compensation circuits can be made to compensate for changes

in temperature of T

1

. These often involve the use of a thermistor circuit.

Thermocouples are in general used for measuring high temperatures. A

thermocouple combination of a 70% platinum and 30% rhodium alloy in a

junction with a 94% platinum and 6% rhodium alloy, is known as a type B ...