Modulator Amplifier (V1574E)

This circuit is from a 1938 tube manual. Transformers are the critical components. Component values are given.

200 mW NEC 200A Amplifier (CB18422E)
This NEC commercial amplifier was manufactured in Japan in the 1960s. The circuit uses 4...
Voltage Controlled Oscillator (CB19732E)
The operational 3403 is not currently common, but a similar configuration can be made with modern...
Avalanche Divider (CB6834E)
We found this circuit in an American documentation from 1969. The circuit works with the polarized...