THE CATHODE RAY OSCILLOGRAPH 



23 



Fig. 31 — ^Hysteresis curves (a) of iron, {b) of permalloy. 



phase. These two voltages are applied to the deflector plates, pro- 

 ducing a stationary circle on the screen. The voltage from the oscil- 

 lator of higher frequency is introduced in the circuit between the 

 cathode and anode of the tube so that the sensitivity of the tube is 

 varied in accordance with the higher frequency. The circle is dis- 

 torted into a gear-wheel shape as shown in Fig. 34, provided that the 



.140 WATTS 



.170 WATTS 

 INPUT VOLTAGE 



.275 WATTS 



Fig. 32 — Distortion in vacuum tube amplifier.-^ 

 26 Willis and Melhuish, Bell System Technical JL, 5, p. 573, 1926. 



