Crystal oscillator with a 6A6 (T437E)

We found this circuit with the 6A6 double triode in a 1938 Radio Handbook. The power source is not provided.

Noise suppressor for triacs (CB6740E)
A 100 nF capacitor and 100 uH inductor form this circuit suggested by General Electric in a 1964...
Reset Pulse Generator (CB6615E)
This circuit is from Dutch documentation from 1967. The circuit works with a component of the...
27 MHz Modulated Transmitter (CB19450E)
This is the modulated version of the previous 2 W transmitter circuit (CB19449E). The circuit has...