Found in na 1969 Electronics World, this circuit makes use of transistors of the time. Equivalent transistors can be used. The diodes can be 1N4004.
This circuit is intended to reinforce old car radios, having been found in 1997. At that time,...
The Sample and Hold circuit shown in the figure was found in a 1994 Linear Applications Handbook by...
Found in a 1980s documentation, this circuit detects when the voltage drops below 11 V. Other...