This circuit with TTL compatible output was found in a 1968 US documentation. The circuit is powered by 5 V and the frequency can be changed by changing the crystal.
Found in a 1991 publication this circuit can be assembled with more modern components. We can use...
We found this circuit in a 1987 documentation. Its purpose is to turn on a garage light using the...
This is the circuit of a turntable from the 1970s. We found it in a repair article in the December...