Step-down power supply for driving relays

When developing some electronic and electrical circuits, it is often necessary to use DC relays to execute automatic control circuits. The low DC voltage supplied to the relay is generally supplied after voltage reduction and rectification by a transformer, which is costly and complicated for some simple electronic circuits. If a resistor and a diode are connected in series to rectify the DC output, and then the DC voltage obtained after capacitor filtering and voltage stabilization is directly supplied to the relay coil winding working voltage, it is very easy and convenient. Of course, 4 diodes can also be connected in series to form a bridge rectifier circuit, and the effect will be better. See the figure for the wiring of circuit components.

Please pay close attention to safety!