Battery test (CB9132E)

Found in old documentation, this simple test checks both the polarity and the existence of voltage in batteries.

Untuned Crystal Oscillator (CB4049E)
The frequency of this oscillator is determined only by the crystal, without the use of tuned...
Electroscope (CB4341E)
This simple electroscope with bipolar transistors is not the most sensitive, but can detect static...
Half wave dimmer (CB7204E)
Found in a 1965 Motorola documentation, this circuit uses a neon lamp as a trigger element. The SCR...