This circuit uses a General Electric coupler from the time of the publication in the 1980s. Equivalent SCR can be used.
This circuit was found in a1980s Motorola documentation. The integrated circuit is from that time....
This circuit is from General Electric from the 80s, using a relay with high current contacts (20...
This circuit uses an LDR as a sensor to trigger an LED indicator at a preset lighting level. The...