| Electronics > Beginners |
| How use salvaged transformer to make a variable dual bench power supply???? |
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| Dhanushka:
Dear all, I salvaged a transformer from an old Sony stereo audio system. It has 2 x 12 V/2 A (center tapped) and 2 x 20 V/3 A (center tapped) outputs. These wingdings are isolated for the continuity testing. But when I measure the voltage they had relative measurements. However, I use two lines of 12 V as an 24 V input to a variable lab power supply module. (https://www.aliexpress.com/i/32769033201.html) Also, one 20 V output as a input to another power supply module to make dual output power supply. But when I made this I could not make dual power input to a circuit combining the as two separate power supplies. (positive of one is connected to negative of another) When I connect these two, current limiting indicator glows. The negative lines has a voltage drop of about 4 V. Please tell me how use this multi output transformer to make a dual variable output power supply? |
| xavier60:
That should work. With the power off, do you find any continuity between the output terminals of one module to the other? Also check between the windings again. Maybe there is something on that transformer connection PCB. |
| tautech:
Transformer winding phasing is most likely wrong. Disconnect prior to the rectifiers and experiment with secondary connections using a bulb that will indicate glow when phasing is wrong. |
| tunk:
The heatsink in the front of the photo looks a bit small - what's the max current will you draw from that one? You may also want to add a fan at the back, and ventilation holes at the sides. |
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