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 a 2000 publication with the purpose of protecting a three-phase circuit by...
This circuit indicates the logical level of a CMOS circuit, extracting the power from the circuit...
The circuit shown in the figure is in fact an excellent symmetrical switching source capable of...