This circuit, which can use the 4011 or 4001, was found in documentation from the 90s. The load depends on the transistor used, and the power supply must be isolated.
This circuit is from an American publication from the 60's. The power is on the order of 600 mW....
Other operational amplifiers series, such as the MC34072, MC34074, MC35071, MC35072, MC35074 d...
Found in a European magazine from the 90s, this circuit emits beeps that are several seconds apart to...