Using 555 integrated circuits, this alarm circuit was found in a 90s American documentation. The signal must be applied to a good audio amplifier.
July 13, 2015 - Mouser Electronics, Inc. today announced that it has signed a global distribution...
Found in an Electronics World of 1968 this circuit can use current SCRs and the diodes are...
This circuit came out in an English publication from 1973, but it can be easily assembled using...