I previously posted on this board as to how to reduce the voltage and got suggestions for various items that would do the trick. Based on the recommendations I bought: Buck Step-down Power Converter Module DC 4.0~38 to 1.25-36V LED Voltmeter zhn Now I want to test this item before installing. Using jumper leads, I have connected my transformer fixed DC to the input on this device. I have nothing attached to the output and the device is not mounted. I intended to apply juice and then adjust the device to 12 V, but all I get is the transformer indicating a short. To do a complete test does it need to have output hooked up and/or does it need to be mounted in order to get adequate test results? Also, a small piece of aluminum channel was included, but I'm not sure what the function of this piece is. Thanks for any help on this. Jim
to check output on a small transformer, the output should be loaded close to maximum load allowed. if it states what the load on the fixed voltage portion should be ... it's normally higher at lower load factors, depends on internal construction
Looking at other suppliers of this board it seems that the aluminum channel is a heatsink and suggests that it should be attached to the power ic if the output required is going to exceed 50 watts.
What is the power IC? I am just trying to test if this gizmo works and set it for approximately 12 V, but I'm not having any luck. What do I need to hook up in order to test the unit and set the voltage? For right now, the voltage does not need to be perfect as I have a range from 12-16 V.
Did you observe the correct polarity of the DC input when you connected the fixed DC to the buck converter? That'd be my first guess. I wouldn't think the converter would need a load to show an output voltage.
Thanks. Got it tested and set. Does the heat sink attach to the small black piece with the 5 terminals? Seems like that is where it physically fits, but don't want to attach to the wrong piece.
That's good news! My guess would be the same as yours on the heat sink location, but I'm not sure. I think that's the transistor. How does the heat sink attach? Did the Seller include some sort of special heat-transferring paste to affix it?
This page shows a similar module with the heatsink attached: https://www.amazon.com/JacobsParts-Step-Down-Converter-Adjustable-Regulator/dp/B07J9JX5RG
It would seem that you need to install a 12v zener diode or a 12 regulator I’ve just converted three 32v AC to 15v and 12v DC supplies for my layout
These step down boards are great if you tinker with electronics that need different voltages. I have one on my workbench all the time. BTW, the practical reason that you don't need a load attached before plugging the board in is that you need to set the voltage before powering the load lest you let the smoke out.
