Capacitor power supplies or transformerless power supplies are small but effective power supplies for small appliances like sensor boards, microcontroller boards, etc. This type of power supply is small in size, light in weight, and low in cost. Which can replace its counterpart of transformer-based power supply.

Circuit diagram of Capacitor power supply:

In this table below put your values, the calculator will calculate the output result. This Capacitor Power Supply calculator is designed taking the calculation from Application Note AN954.

Input variables:
Line frequency Hz
RMS voltage V
D1 (ZD) breakdown voltage V
C1 nominal capacitance uF
R1 nominal resistance Ohms
D2 forward voltage drop V
C2 capacitaance value uF
C1 tolerance %
R1 tolerance %
Design Results:
Nominal output voltage below current limit V
Output ripple at nominal current mV
Available nominal current mA
Worst case available current mA
Best case available current mA
Worst case R1 power dissipation (pick double) W
Worst case D1 power dissipation (pick double) W
Worst case D2 power dissipation (pick double) W
Minimum rated voltage for C1 (pick double) V
Total consumed power max W

You can also read this article for the explanation of this Capacitor Power Supply calculator: Transformerless power supply design guide in detail with calculator


I hope this Capacitor Power Supply calculator will help you save lots of time. There are lots of useful articles are being published on this site regularly. Don’t forget to subscribe to get updates. Thanks.


JLCPCB – Only $2 for PCB Prototype (Any Color)

24 Hours fast turnaround, Excellent quality & Unbeatable prices

$18 Welcome Bonus for new registrations Now!!!

Lab Projects BD

This is a personal electronics blog. The author loves to write on different topics and shares his knowledge to help others.


Leave a Reply

Avatar placeholder

Your email address will not be published. Required fields are marked *