Introduction: Small Portable Variable Power Supply

Idea is to make small cheap portable variable power supply for hobbyists. It main purpose is to test some electronic components or to power some projects in their early development or for POC stage.

Step 1: Parts

Parts used in project are:

- Digital voltmeter/ammeter - DSN-VC288

- DC-DC step-down buck-converter - LM2596

- 10k potenciometer

- 2 output terminals

- 2 input terminals

- switch

- some wires

- some case from cream or something

Step 2: Installing Components

Most important step is to drill holes carefully to fit all components on box. It is recommended to have some kind of drill or something, but scalpel should be just fine, just don't cut your self :)

If your box is too thin you can double it, as I did to make box stronger, it also helps when pressing switch or using output plugin terminals.

Step 3: Wiring

As its quite cramped be careful when connecting component to make sure you there is no possibility to short circuit something, you can secure connections with hot glue.

Step 4: Calibration

If you really want, you can calibrate voltage and amp measurements. It's quite simple. On DSN-VC288 there are two potentiometers I-ADJ for calibrating current, and V-ADJ for calibrating voltage measurement.

Calibrating voltage measurement can be done simply by connection output to voltmeter and screwing potentiometer until values match.

Calibrating current is done on same way its only necessary to connect amper meter in series to load and again screw potentiometer to match values.

Step 5: Finally

Final result is here!

Its quite portable, small size and pretty useful variable power supply for hobbyists. Its abalities are limited by buck-converter and Volt/Ammeter. Input voltage can be up to 4.5-30V. It can output according to the value of voltage applied in this range, the output voltage of 1.25-30V, 3A max.

Here is small demo.