Found in a Popular Electronics from the 1990s, this circuit is a 1-digit counter that advances under the command of S2. The circuit can be expanded to more digits.
This control panel allows the use of NO and NC sensors, turning the alarm on after 30 seconds...
This circuit, found in a 1989 publication, only works with incandescent lamps. The maximum power...
We found this circuit in a 1968 Electronics World. The potentiometer should be set to trigger the SCR...