Found in an American publication from the 1980s, this circuit can be found in commercial sound equipment of the time. The list with the component values is given next to the diagram.
This circuit was found in documentation from the 1980s. The integrated circuit used is uncommon today...
This circuit activates a relay that has a lamp as a load. The circuit is from a Radio Electronics from...
This circuit was found in a 90s Popular Electronics. The circuit uses several relays in order to...