This low frequency oscillator circuit was found in an Electronic Design from the 90s. The transistors are common types, and the frequency is given by the crystal.
Found in a Popular Electronics from the 90s, it applies to the old answering machines that used...
The operation of this circuit is not common today, but equivalents can be experienced. The circuit is...
This circuit was found in an English publication from 1989. The integrated circuits are of the...