The circuit is from Ferranti's 1974 transistor manual. Transistors are general purpose types, and the output waveform is rectangular. Components can be changed to other frequencies.
This circuit is from the documentation of Radio Shack 1975. It can be mounted with 12 V relays,...
Using an optocoupler this circuit turns on the light in a bedroom for a set amount of time when...
This circuit is used for remote current monitoring. In the original version of the 80s a lamp is...