motorboating shielding power supply capacitors

Zener Diode Power, Pz = Vz x Imax = 12 x 0.046 = 0.552W.As per the above calculations, C1 = 680nF, 400V.In the negative half cycle diodes D2 & D3 gets forward biased and the output voltage will get clipped by the zener effect of diode D2.Ĭurrent I = V/Z, where V is the voltage and Z is the impedance.Ĭapacitive Reactance X C1 = 1/(2πfC), where f is the frequency and C is the capacitance. Output voltage will be clipped by the zener effect for diode D1. In the positive half cycle diodes D1 & D4 gets forward biased and current flows through the load. Working is self explanatory in the above animation. Working Capacitor Dropper Power Supply – Working Animation Capacitor C2 is the filtering capacitor which will filter the rectified ac voltage. So the rectified output will gets clipped at its zener voltage. Resistor R2 is provided to prevent excess transient current that can flow when the power supply is switch on.ĭiodes D1 ~ D4 constitutes a bridge rectifier which will rectify the input ac power. Which will discharge the capacitor when the supply is switch off, so it will prevent any shocks due to capacitor charge. The resistor R1 is the bleeder resistor for capacitor C1. The excess energy will not dissipated as heat as we are using capacitor dropper instead of resistor. The X Rated Capacitor C1 is the core part of this power supply as it will drop the excess mains voltage across it.

The 275V MOV (Metal Oxide Varistor) will protect from power supply spikes or surges.

The 200mA fuse will protect the circuit from mains during shot circuit or component failures. Circuit Diagram Transformerless Capacitor Power Supply 12V 40mA It is low cost and light weight since there is no bulky transformers. Capacitor power supplies are simple, low cost and light weight solution for providing dc supplies to circuits which require low currents. Here we will see how to design a capacitor dropper power supply. I already posted about transformerless power supplies in the article, Transformerless DC Power Supply.

3.2 Component Ratings for 12V, 40mA Supply.

Motorboating shielding power supply capacitors