Dual function timer (CB20363E)

This circuit was found in 80's telecom documentation. Its purpose is to control a microphone in the process of transmitting voice and Morse signals.

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Geiger Detector (CB4390E)
This circuit was found in a 1962 publication. At the time there were high voltage batteries like the...
Ionization chamber gas detector (CB9811E)
Found in documentation from the 1980s, this highly sensitive circuit is based on the conduction by the...
Power zener (CB21503E)
In the figure we have the way to implement a power zener diode. The voltage depends on the zener,...