PROPERTIES AND USES OF THERMISTORS 



203 



WTiere the ambient temperature sensitivity of the thermistor is dis- 

 advantageous in oscillator controls, the thermistor can be compensated by 



Fig. 20A. — An amplitude control thermistor. The glass bulb is 1.5 inches in length. 



I0-* 2 4 6 810"^ 2 4 6 810'^ 2 4 6 8I0'' 2 4 6 8 | 



CURRENT IN MILLIAMPERES 



Fig. 20B. — Steady state characteristics of amplitude control thermistor shown in 

 Figure 20A. 



thermostating it with a heater and compensating thermistor network, as 

 shown in Fig. 21. 



Amplifier Automatic Gain Control 



Since the resistance of a thermistor of suitable design varies markedly 

 with the power dissipated in it or in a closely associated heater, such ther- 



