5-tube commercial radio (T1619E)

This commercial superheterodyne receiver was found in a 1949 Radio Electronics. The circuit uses battery.

3 Power Control (CB6569E)
Suggested by General Electric this circuit has 3 control positions for one load. The diode is...
Audio Compressor and Amplifier (CB4754E)
This circuit was found in a 90's Electronic Design. It takes advantage of the nonlinearity...
Analog meter tester (CB7064E)
With this circuit from Popular Electronics it is possible to determine the characteristics of a microammeter...