walid Posted March 12, 2012 Report Share Posted March 12, 2012 What is the function R3 If you know that the output voltage at both ends of the 220u capacitor is 9 volts DC, is not this resistance wastes 9mAh all of time What is the point of that?thanks Quote Link to comment Share on other sites More sharing options...
audioguru Posted March 13, 2012 Report Share Posted March 13, 2012 If the transformer is low quality (cheap) then its output voltage is very high when there is no load. I have a cheap AC-DC wall wart with a rated output of 9V/100mA and its output is correct. But without a load its output is 19VDC.The 1k resistor R3 provides a load when there is no other load to keep the output voltage from being too high. Quote Link to comment Share on other sites More sharing options...
walid Posted March 13, 2012 Author Report Share Posted March 13, 2012 thank you guru, yes the transformer is cheap Quote Link to comment Share on other sites More sharing options...
alok81 Posted March 14, 2012 Report Share Posted March 14, 2012 i agreed with audio guru ;) Quote Link to comment Share on other sites More sharing options...
Will D Posted March 15, 2012 Report Share Posted March 15, 2012 Hi,I agree with audioguru. 1k resistor R3 provides a load when there is no other load to control output voltage . Quote Link to comment Share on other sites More sharing options...
bassamfreiha Posted July 8, 2012 Report Share Posted July 8, 2012 If the transformer is low quality (cheap) then its output voltage is very high when there is no load.Ac Dc is not supported in this transformer.So you can many option to new transformer high voltage load. Quote Link to comment Share on other sites More sharing options...
Guest remonx6 Posted August 1, 2013 Report Share Posted August 1, 2013 yes i agree with walid . yes the transformer is cheapThanks Sir Quote Link to comment Share on other sites More sharing options...
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