This is the circuit of the commercial Japanese megaphone of the 60s model DM-218. The circuit uses a compression speaker (horn) and is powered by 4 large batteries. The output power is 2 W.
Found in Linear Technology documentation from the 90s, this circuit uses an operational amplifier...
This simple circuit that interrupts the supply of a 12 V load in the event of an overvoltage was found in...
The circuit shown is from National Semiconductor, having been found in the 1994 Linear Application...