This circuit is from a Radio Electronics from March 1970. The integrated circuit used is one of the first for this purpose, being improved later leading to types that succeeded it.
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...