We found this circuit in a 90s 73 magazine for radio amateurs. The circuit has 3 W of power and can use modern equivalent MOSFETs.
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...