This simple optical alarm circuit was found in the 1991 Electronics Experimenter Handbook. The circuit uses a lamp as the emitter but can use LEDs.
This circuit was found in an American documentation from 1976. We can assemble it with two 741,...
This circuit trips when the input signal goes through zero, triggering a direct current load. The...
January 2017 - New ROHM TFZV series of zener diodes is now available from Mouser Electronics. The...