R1 = 5K6
D1,D2 = 1N4001
Q1 = 2N3904
Ry = Relay, 12V
S1 = Momentary break (normally closed)
This relay driver is Self-Latching which means that once it activates it will remain in that state until S1 is pressed and momentarily disrupts power to the latch.
Copyright © 2003 – Tony van Roon