We found this circuit for receiving shortwave on a mediumwave radio in a 1986 Hobbyst Electronics PE. The circuit has the received band given by T1 which can be an FM IF.
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...