D-PLANET [8-Pack] LM2596 DC-DC Adjustable Buck Converter 3-40 V to 1.5-35v Step Down Power Supply High Efficiency Voltage Regulator Module …

I used these to convert 24V to 12V in order to use Noctua fans with my 3D printer. These worked exactly as expected.

I use this buck regulator in two applications so far and it’s solid. First was to power a 6v backup camera in a Hyundai. I installed an aftermarket radio but wanted to use the factory camera, the problem was that the camera is powered by 6v not 12. This little guy did the trick. At first I thought I got a faulty part because I would turn the pot counterclockwise and the voltage would not change. After some research it turns out that they test these up to the highest voltage before shipping them out and they leave the pot at that setting. So it needed to be turned about 8-10 revolutions before it started to make any difference.That’s with me using a 13-14v input. Obviously if you start at a higher input voltage it will take less turns for you to see a change. The other use for this regulator was for installing a custom microcontroller board in an automotive environment. Similar scenario, I have a 13-14 volt source in the vehicle but I need 5 volts for the MCU. So far they are good. I’m sure you can add a few components to make them better, eg. polarity and overvoltage protection, noise clean up etc…. But for the price you can’t do better.

Finally phased the need for Batteries on my Christmas Village. These fit perfectly (with a little box trimming) into the dual AA battery compartment... also note the shorter capacitor can's than some. I Converted my entire Christmas Village to 12V DC thanks to these.Both of mine are staying below 100 degrees Fahrenheit which is exactly what I wanted for something in a plastic box and under cover. The draw on my fixtures is less than .5A on the 12V source which helps keep the heat it creates low. I tried a Mini-360 buck converter first, but they were over 150 degrees Fahrenheit with no load doing the 12V to 3V DC conversion.The adjustment on this is great. Great control and no drift after I set it and re-checked them several times. The connections are easy to access. Being on the 4 corners allowed them to easily be tested with just alligator clips before adding permanent wires.I selected this set for:1) They have the 470 coil instead of the 300 that I have heard to run hotter2) It includes the heatsinks for when I do projects with higher draw3) It was a good value for the quantity4) The shorter capacitor caps so I could get it in the battery box.It lived up to my needs and expectations.They are Individually packaged within a larger packages so very convenient to use.

While pricing components for my latest project, I found that I can buy these pre-assembled, adjustable, DC-DC regulators for less than it would cost me for discreet 78xx regulators and the other parts to build the power supply section of my project. I needed a way to regulate 36VDC down to 24VDC to drive a pair of linear actuators, and also to 12VDC to drive the acutator control relays. These worked **perfectly** for my purposes. Contrary to some reviews here, I found them very easy to adjust, and they have held their adjusted output very well. I tested these using 2 modules connected in parallel, with both modules wired directly to 36VDC, and adjusted for my 24 and 12V outputs, and then again in series, with one module connected to 36VDC & adjusted for 24V out, and the 12V module connected to the 24v output. Both arrangements worked well, and after verifying that moderate changes to the input voltage and/or load on either module didn't change the output, I decided to use them connected in series. In my project, each of the 4 12v relays draws only 30mA, but the two 24V actuators draw from 0.25 to 3 amps for periods of 2-30 seconds. Even after providing 3 amps at 24V (72W) for 30 seconds, the regulator on this modulator was barely warm to the touch, even without the heat-sink installed. The thru-holes in the input and output solder pads will accept 18ga or thinner wire, and the mounting holes are sized right for #4-40 hardware. I got in a hurry while testing these and let the "magic smoke" out of one module by cross-wiring it. Don't worry, it didn't suffer. When I switched the power on, it died quietly (no flames), with a soft sizzling sound and that special smell that only burned-out electronics can produce. So be sure NOT to connect your INPUT power to -IN and **+Out**, unless you just really like that smell. ;-)

I have used these quite a bit. The weakness is the 10-to-20 turn trimpot. I did some testing and if the pot wiper loses its internal connection (as pots do over time), poof -- there goes whatever these are connected to. The output voltage goes UP not down. That's a backward design. Otherwise, these are terrific when they are working. I have done two different things to protect the circuitry and components that these power. First, I use a separate over-voltage monitoring circuit (OVP - over-voltage protection). It's a watchdog so if/when the pot or other part fails, the OVP knows as a "crowbar circuit" protects things. Secondly, I use a similar circuit with Opto-isolator that I connect up to this board's regulator chip, Pin 5. This pin is the inhibit INHB and is active LOW. This means as long as it's tied to ground or floats, there is output. But, connecting this pin to more than a few volts and it harmlessly shuts down the regulator. So, I use this pin and a "watchdog" circuit to turn off this little jewel at the first sign of voltage runaway. I use these mostly for +5v. I set them for precisely +5.05. If the voltage reaches uncontrolled +5.5v, one of the two methods I mentioned will kick in and shut down this board. Finally, in cases where the circuits being powered are more expendable, I have removed the trimpot and replaced it with a fixed resistor value selected to provide the output desired. Any engineer who has been around the block knows that trimpots eventually do develop noise. The best brands of trimpot in my opinion are Bourns. Most of these boards use a word to resemble this brand but they are NOT. That's a clue so it's your call. These BUCK boards are a great substitute for heat-laden linear 7805s, 12s, or whatever. Highly recommended.