This circuit was found in the April 1983 issue of Radio Electronics magazine. Its purpose is to couple an antenna to two receivers without problems with coupling losses.
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...