Greetings. I am going to use 12V converters for my control panels. (Older Digitrax 12V units). I have a couple of these already, plus a couple of more at different brands. When I measure with both of my multi-meters, I am getting 19.6VDC. I've tried this on 2 meters I am using the multi-meter set on V DC (=) The meters both work fine when checking out other items I have the leads correctly connected into the V and common ports. Both meters have fresh 9v batteries. Both transformers have had very little use. I guess my question is what are the chances BOTH would bad and beyond that, if so, then what are the chances both are reading 19.6V. When I check out one of the newer Digitrax 14V meters, it is reading, well right at 14V. Any suggestions or experience here? Not sure why this gremlin is rearing its head on this.
I would think that some place on them they would have the input voltage and amps and the output and amps. If so what do those say? Sumner
Thanks… Input V on the xfrmr 120. Amp doesn't matter because I am measuring at no load. However, secondary rating for the unit I am measuring is 300mA. Or, 15 LED’s. I may have 10 max on the 1st few panels. Later panels will have more and I will probably get 750mA units for those.
Some (typically older) power supplies do not regulate well without at least a minimum load (current). If you don't have a load that will do, get an automotive lightbulb and measure the voltage when driving that. The wattage of the bulb should not exceed the wattage rating of the supply. Keep in mind that incandescent lightbulbs can draw a lot of current immediately upon being turned on, then they quickly heat up and lower the current according to their wattage. But I'd be careful that some electronics might not be happy powered up with a a supply like that. It could shorten their life.
Thanks Jake! I had not considered applying a token load to stabilize the converter. I've got a few things in my workshop I can load on to it and check it out. Let me see how that works.
Okay. So I tried this with a 12V bulb, then on a breadboard with various LED's, resistors, and even a couple of Tortoise motors. At rest, the output voltage at the immediate secondary of the converter was all over the place depending on load. The output terminals dropped from 19V to 15.5, then 16. something, then 18.3. All depending on load. I then measured a 5V supply I have that IS regulated and it was a steady 5V. After reading around on regulated vs unregulated supplies, I found a 12V supply on Amazon that can be delivered later today. 12VDC regulated and rated at 5A. I'll try that, but I think I have this solved. I don't want this thing load dependent. I want something that will hold voltage at RATED voltage output at varying loads as long as those loads are at or below its rated, sum wattage. Thanks again for pointing me in the right direction.
