We found this circuit in Radio Electronics Special Projects from 1992. The circuit turns on the power when the microphone plug is inserted into the input jack.
Frequencies up to just over 100 kHz can be obtained with an oscillator based on one of the four...
This circuit, found in a Popular Electronics from 1992, is based on an oscillator and a crystal...
This is a discrete equivalent version of an open collector TTL gate. What we have is an inverter...