This simple circuit with two transistors was found in a 1985 publication. The power can come from batteries or battery, as consumption is very low.
This TTL trigger circuit with the 7400 can be used as a signal conditioner in an input shield for...
This circuit can be adjusted between 0.2 and 2 V to trigger with chosen voltages comparing them with...
With this circuit (shield) we can control a load from 500 mA to 1 A, depending on the transistor, using a...