Found in a 90s EDN, this circuit uses components from that time. The circuit supplies a current of 100 mA with a 5V voltage.
This is a project that can easily be adapted for other purposes such as counting people, objects,...
A modulated (intermittent) siren, using the four gates of the 4001 integrated circuit is shown in the...
This circuit was found in July 1986 Radio Electronics magazine. The maximum current is 1.5 A. The...