This circuit supplies 5 V from two AA batteries. The output current is 4 mA, resulting in an 11 mA input current from the batteries. The circuit is from an old EDN.
With this circuit, a relay can be activated from an alternating signal with frequency up to a few...
With this circuit the visually impaired can easily locate important places inside the house, such...
In the figure we have the way to use the transistors of an old-paired pair as a trigger circuit. The...