A buck converter is a voltage regulator, but more efficient then the linear voltage regulator.

A buck converter (step-down converter) is a DC-to-DC power converter which steps down voltage (while stepping up current) from its input (supply) to its output (load).

A buck converter is a “switching regulator”, turning the power on and off quickly all the time, compared to the linear voltage regulator which dissipates the excess power as heat.

## A very small adjustable buck converter from Ali Express

I bought this 5-pack of very small buck converters from Ali Express and have just received and tried them.

They come preconfigured with adjustable voltage, by turning a small screw on the top. One can also fix the voltage level at 1.8, 2.5, 3.3, 5, 9 or 12 volts by soldering a little on the backside.

### Connections

There are four connections on this buck converter.

• VO+ Regulated voltage output
• GND Ground
• IN+ DC 4.5-24V (according to Ali listing)
• EN Enable (I have not tried this one. The converter works without it.)

### Fixate the voltage level

Please see the photo below to understand how to permanently fixate the voltage level.

Now you have a stable voltage level coming out from the VO+ connection.