Best Regards,
Lou
24.209.14.81
In Reply to: Re: 12V DC power supply voltage too high posted by mc1b on September 5, 2006 at 04:47:17:
The voltage is determined by the transformer, unless there is a voltage regulator in the circuit. The rectifiers merely change what is there into D.C., the caps merely filter the D.C. IF there is a solid state voltage regulator, you can replace it, it's faulty. If not, you are going to have to try one of 3 things. You could roll the dice and see if the circuit can handle the higher voltage over time, I would not recommend that. You could use resistance to form a voltage divider. Use a 0-1K potentiometer in series with the load, make sure the pot is at 1K, measure the voltage across the input to your load while turning the pot. When the voltage is at 12 volts, turn off the power, pull the pot out of the circuit, and read the resistance across the pot. Replace it with a resistor, a 10 watt resistor should be fine, if it gets too hot, you'll need to go with one you can heat sink. Do not touch the resistor, feel the temp by placing the back of your hand near it, it will burn you if it's hot and you touch it. If that sounds too complex, it's time to find a new power supply.
Best Regards,Lou
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