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 circuit detects traffic problems on a miniature railway by triggering an alarm. The circuit was...
When establishing the voltage at the input of this regulator, the output voltage rises smoothly until...
This circuit was found in a Motorola documentation from 1975. Modern equivalent transistors such...