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.
It is like to the previous circuit with a lock that keeps the LED on at the end of the timer. The...
The presented circuit generates a signal in the form of a ladder that can be useful for surveying the...
This 2005 Linear Technology circuit has separate outputs for monitoring the charge and discharge...