This circuit takes advantage of the hysteresis of a relay to provide a latching effect. The circuit acts as a trigger and the components must be according to the used relay.
Equivalent transistors, such as the BC548, can be used in this circuit that we find in...
Found in a 90s documentation, this circuit makes use of D1, a switching diode that is uncommon today....
This is the suggested transmitter circuit for the CB16880E. The emitting LED must be a...