This circuit makes use of a specific 80's component and was found in an American manual of the time. A matrix keyboard allows you to select one of several music programs.
This indicator circuit used and game machines (arcades) to indicate that the machine is being...
This circuit fires at the touch of a sensor, passing its output from high to low in a time given by...
This circuit is from an English magazine from 1978. The circuit can be assembled with BC557, BC547...