DC-DC Bucker Converter

Part no DFR0379 I am having trouble getting the output of the buck converter to change the voltage down to 5v from a 12 volt input. I have followed the instructions provided by the manufacturer which is to hold the button down for 3 seconds which then enables me to select a value between -5 and +5 on either the input or output options. When doing this I can only change the input or out displayed on the display down by about 1. Any help appreciated.

Hi @David23531,
What have you set the output voltage to? The actual output voltage is set by the trimmer-potentiometer - the small brass screw adjustment, on the opposte edge to the display; You can turn it multiple times in either direction to adjust the output voltage.

The calibration method you describe is for finely adjusting the readout that is displayed on the LED display, which might explain why it only has a range of about ± 1V.

Hi Michael, I tried turning the little brass screw in either direction and did not seem to change the numbers shown on the display.

Hi Michael, I solved the problem, I had to turn the brass screw quite a few rotations before it started to change the voltage.


Brilliant to hear @David23531! Those blue trim pots are usually 10-turn, but you’ll find that some go as high as 25 turns.