This circuit is from General Electric from the 80s, using a relay with high current contacts (20 A). The transistor admits equivalent, and any phototransistor can be used as a sensor.
This is a Philips commercial circuit from the 1980s. The circuit must be powered by 28 V and its...
Only the right combination of the positions of the 6 rotary switches of 1 pole x 10 positions of...
This circuit is from an April 1988 Radio Electronics magazine. The circuit is retriggerable and...