This circuit was found in a Popular Electronics from the 90's. Its purpose is to detect the ionization of the air. The meter can be replaced by the current scale of an ordinary multimeter.
Found in a publication from the 60's, this circuit uses the CK722, germanium transistor of the...
From an input signal, and using an unusual current source, this circuit generates a ramp, that is, a...
With this timer we can start between 30 seconds and one and a half seconds, time set in the pot....