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 a 1970 American publication. The FETs are power types according to the...
This circuit is from a 1974 publication. It generates a pulse with several sinusoidal cycles from...
Suggested by Philips in 1966 documentation, this limiter can be found elsewhere on this website....