This alarm circuit with NC sensors in series was taken from an article in Radio Electronics magazine from May 1971. The SCR can be any of the 106 series.
The four gates of a 40111 IC are used in thes two-out circuit. The output chages their state in a...
This low power, low voltage circuit was found in old General Electric documentation. Transistors may...
This grounding test circuit was found in an American 80's documentation. The circuit is for the...