Guest Posted December 30, 2004 Report Share Posted December 30, 2004 I found an DC adapter designed to give 12V output. When i checked the output by a multimeter the reading was 23V approx.I switched it off but the multimeter still maintained that reading and then the value started to decrease slowly.On this, i shorted the capacitor in it (1000microfarad/25V) so the reading becomes zero.I switched on the adapter again and the reading again reached 23V.Something is wrong in the capacitor, but how is it happening. I have never read anywhere about anything like this.The multimeter is fine. Quote Link to comment Share on other sites More sharing options...
ante Posted December 30, 2004 Report Share Posted December 30, 2004 Hi Siddharth,This is completely normal for this kind of DC adaptor. It can be fatal to any low current 12V circuit so be careful when using it for anything other than what it is designed for. Whatever it is designed for can be equipped with a built in regulator and is then safe. There is some kind of marking on it telling you how much current it Quote Link to comment Share on other sites More sharing options...
trigger Posted December 31, 2004 Report Share Posted December 31, 2004 It is the matter of the "ON Load" and "OFF Load" voltage. They are normal. Quote Link to comment Share on other sites More sharing options...
Guest Posted December 31, 2004 Report Share Posted December 31, 2004 The adapter is to be used on a cordless phone. I'll see further.Thanks!!!!!!! Quote Link to comment Share on other sites More sharing options...
autir Posted January 2, 2005 Report Share Posted January 2, 2005 Check these out:http://www.electronics-lab.com/forum/index.php?board=21;action=display;threadid=2308http://www.electronics-lab.com/forum/index.php?board=21;action=display;threadid=2336Regarding the slow decrease of the voltage when you unplug the adaptor, it is absolutely normal. It is a simple discharging RL circuit; L because the transformer of your adaptor has an inductor and R because voltmeters have big resistances. Quote Link to comment Share on other sites More sharing options...
steven Posted January 15, 2005 Report Share Posted January 15, 2005 :)ive had that to i have a bag full of transformers and every one has its voltage output written on them but when i measure all there voltages they are more than what they say on the transformer Quote Link to comment Share on other sites More sharing options...
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