Multi Tube Amplifier (T446E)

Obtained in MIT documentation this circuit uses several tubes to obtain a large gain in the amplification of small signals.

Doubler Crystal Oscillator (CB20664E)
This circuit was found in Radio Electronics from the 90s. The circuit can generate signals up to...
Stereo indicator MC1310 (CB22122E)
In the figure we show how to add an indicator LED to an MC1310 stereo decoder. The circuit is from...
Luminous intensity meter (CB23621E)
This photocell circuit was found in Radio Electronics magazine from July 1959. The transistor used...