This circuit can use 20 to 100 mA relays with a general-purpose transistor such as the BC538. The circuit has a 4.7 to 10k pull up resistor. Found in Radio Electronics July 1985. R is 1k.

This circuit can use 20 to 100 mA relays with a general-purpose transistor such as the BC538. The circuit has a 4.7 to 10k pull up resistor. Found in Radio Electronics July 1985. R is 1k.