This circuit uses a contactor having been found in a 1987 publication. More modern equivalent devices may be used. The circuit has neon indicator lamps.
This circuit uses a PNP transistor to modulate a low power infrared LED. Observe the polarity of...
The integrated circuit used in this configuration is uncommon today. The diodes are for general use...
Although the integrated used originally is uncommon today, more modern operating equivalents can...