High Precision Digital AC Energy Meter Circuit

sam.moshiri · August 5, 2022

Dealing with the 220V-AC mains voltage and measuring the AC loads' true power, voltage, and current parameters are always considered a big challenge for electronic designers, both in circuit design and calculations. The situation gets more complex when we deal with the inductive loads because inductive loads alter the sine-wave shape of the AC signal (resistive loads don’t).

In this article/video, I introduced a circuit that can measure the AC voltage, RMS current, active power, apparent power, power factor, and energy consumption (KWh) of the loads. I used an Arduino-Nano board as a processor to make this more educational-friendly and attractive even for beginners. The device independently measures the aforementioned parameters and displays the results on a 4*20 LCD. The measurement error rate is around 0.5% or lower.

To design the schematic and PCB, I used Altium designer 22 and installed the missing component libraries using Altium’s manufacturer part search. The Octopart website allowed me to quickly gather information about the components and make a BOM for the project. To get high-quality fabricated boards, I sent the Gerber files to PCBWay and used the Siglent SDM3045X benchtop multimeter to calibrate the board.

It's a cool device to be used in everyday electronics, so let’s get started 🙂