Suggested by a 90’s Radio Electronics, this circuit automatically activates the recording switch of an old tape recorder. It can be adapted for other purposes.
This circuit, found in a Popular Electronics from 1992, is based on an oscillator and a crystal...
This circuit was found in an Experimenters Handbook of the 1990s. The purpose of this circuit is to...
The configurations of the two previous circuits can be modified to operate with a simple power...