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 is from old documentation. The operational amplifier is uncommon nowadays. The...
This memory flip-flop must be powered by 5V voltage. The circuit stores 1 bit. ...
This simple preamplifier was published in Radio Electronics magazine in February 1958. The battery...