Circuit diagram to reduce relay coil power consumption

　　This is an RC circuit with a series coil that can control the full current, making the relay work reliably, reducing the current and saving power consumption.

　　The highlight of this circuit is that as long as you add two of the most common components, a resistor and a capacitor , you can keep the relay coil closed stably, even if the driving voltage decreases, it doesn't matter. What ordinary electricians do is quite troublesome, take a look at our simple method.

　　Power dissipation in relay coils can be reduced by capacitors and resistors

　　The emitter stage of the relay driver transistor is connected to ground, and the resistor and capacitor we added interrupt it. When the drive transistor is off, R2 ensures that the capacitor is discharged. When the relay turns on the drive transistor, the capacitor acts as a short circuit, allowing maximum current to flow through the relay coil and remain closed.

　　When the capacitor charges, the voltage and current in the coil drop. When the current through the coil is transferred to R2, the voltage and current of this circuit stabilize. Of course, even if the driving voltage is gone, it will still remain closed.

　　The resistance added is about twice the resistance of the coil, 390 ohms for the resistor and 200 ohms for the coil . The capacitor is 150uF, 25V