Low Cost Constant Current/Constant Voltage power supply

  • Posted 1 May 2016

A project required me to provide 3.3v and 5v with current limiting for testing.
The normal breadboard power supplies would not suffice. A benchtop power supply is too expensive, much less 2 of them.

Solution ?

A DP30V3A variable voltage supply module (Aliexpress link) from china. These modules have an LCD screen to select the settings and can provide any Vin-1.2v. Perfect for driving from a switch mode 12v wall wart. Under $25USD shipped.
It even has a fan for handling upto 90Watts.


I built a small enclosure for it from a store bought enclosure and some switches.

For the output I debated between barrel jack and banna jacks.

Most equipment has banana jacks however they tend to be bulky. I had some spare dc barrel connectors from old powr supplies that had died and so I decided to use a barrel jack for the output. It was perfect.
Small footprint, simple connection and lots of options for splitting the output.


The DP30V3A has proven very useful with some of the test projects for the quick ease with you can limit the voltage and current.
Ive grown accustomed to turning the knob while reading the oscciloscope and voltmeter to determine the optimal points in the ciruit.


Some pictures of the build: