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.
We found this circuit in a 1988 documentation, but the components used are still current. The...
This simple timer uses one of the six inverter ports on a CMOS integrated circuit. Rx and Cx...
With an output power of 1.5 W under a 12 V supply, this circuit makes use of transistors that are...