DollaTek Small DC Buck Voltage Converter Step Down Voltage Regulator Module Board 4-38V to 1.25-36V 5V/12V Adjustable Output Voltage Stabilizer Transformer

I was delighted with this little device. I bought a usb lead with open wires both male and female . Which I got from Amazon, tinned ends I fitted them in each relevant end of the board, in out + - . I stuck on the heat sink as per the online picture. I was using it with a £15.99 5volt 10" solar cell I got from Amazon. This to help keep the voltage correct. The solar cell had a female usb A connection that is why I needed the extra wire. I connected it up and to my delight. The little LEDs lit up. I pressed the, in, button and the out one. To find it revealing the voltage in and out. Obviously it's only getting up to five going in poss slightly more. But it seems to have stabilised it from without the board.. Which is great. I will only be using it in the day time. Not when light is low. A sheer delight to receive it. Thanks to the folks who made it and sold it. Exactly what I wanted..... Toppo...

Utter rubbish, does not work as advertised, adjusting makes zero difference to throttle voltage to 12 volt from 13.7 volts

Works perfectly, bought to convert 18v tool battery to 12v for electric cool box for camping great and easy to adjust

If your voltage isn’t changed by moving the POT, go crazy with a screwdriver moving it clockwise and anti-clockwise. After 10sec of fast moving the display with start working!

Only negative point so far is the lack of any documentation. That said it seems well constructed and, on the bench, it seems to do what it claims. The meter for both input and output match the values on my multimeter (but only show one decimal place rather than 2) but that is fine. I wanted an initial output of 3.7v and, although the meter functions accurately down to 4v below this it shows 3 dashes. However, I could achieve a stable output at 3.7v, checked with my multimeter. The type of adjustable potentiometer used was familiar to me and these often take 15 or more full turns end to end to allow fine adjustment. Put the supplied standoffs on and/or make sure you are resting on a non-conductive surface before applying power. Remember a lot of turns anti clockwise to go down on the output voltage. Set the output voltage before you connect your device.

Product arrived already useless. It lights up, but the output voltage adjuster does nothing rendering the item completely useless. Am returning to Amazon for refund.

A handy device to step down and regulate power to a specific voltage. I have a couple providing 5.1V outputs from a variable 12-20V input which have been running continuously for about 6 months. I've recently bought another. The display is a handy addition. It can measure input or output voltage or can be switched off. The module has decent regulation, supplying steady voltage to fast transient loads which can be a problem with switched supplies. It's not running at maximum but at about 50% rated load keeps pretty cool with the provided stick-on heatsink.

The potentiometer was working when I got it, but the voltage would not show on the display below 4v. Could be a quirk of the battery holder I was using.

De momento funciona bien. Lo importante lo hace o sea reduce la tensión. No he podido probarlo exhaustivamente.

Works as expected

convertisseur mini , mais parfait , avec en plus un afficheur visualisant soit l'entree , soit la sortie.Livre avec les colonettes de vixation et un petit radiateur (trop petit) .Plus besoin de passer son temps a le realiser soit meme.

Doesn't change voltage like advertised. I wound up not using it.

Ich bin sehr zufrieden mit diesem Spannungsregler! Das Modul ist leistungsstark (bis 5A) und läuft stabil mit sehr geringer Welligkeit genau das, was ich gesucht habe. Die grüne LED-Anzeige mit integriertem Mini-Voltmeter ist super praktisch und lässt sich einfach über das Potentiometer kalibrieren. Allerdings braut man schon einige Umdrehungen. Besonders gefällt mir, dass sowohl Ein- als auch Ausgangsspannung auf Knopfdruck angezeigt werden dank der "IN"/"OUT"-LED ist das sofort klar ersichtlich. Auch die Möglichkeit, das Voltmeter per Taste ein- und auszuschalten, ist ein tolles Extra. Der Kühlkörper sowie die Kupfer-Säulen sorgen für eine gute Wärmeableitung. Kurzschluss- und Überhitzungsschutz geben mir ein sicheres Gefühl bei der Anwendung. Die Anschlüsse sind sehr benutzerfreundlich auch ohne Lötkolben lässt sich alles problemlos verkabeln. Habe das Produkt seit März 2025 in Betrieb und noch keine Mängel festgesellt. Insgesamt ein hochwertiges und durchdachtes Modul zu einem sehr fairen Preis. Klare Kaufempfehlung für alle, die mit variabler Stromversorgung arbeiten!