Based on the LF256 operational amplifier, this circuit was found in the September 1989 issue of Radio Electronics magazine. The indicator is analog, and the power supply must be symmetrical.
The components used in this 80's circuit are uncommon today. The circuit is intended for...
This circuit, which combines a bipolar with any JFET, was found in the April 1993 issue of...
This very simple circuit with neon lamps indicates who pressed the button first, lighting the...