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Wall wart marked as 9V, output is actually 15V?  


YurkshireLad
(@yurkshirelad)
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I have a wall wart that is marked as 9V DC output and 300mA. I used it to power a simple circuit on a breadboard with a DC barrel jack. I connected my multimeter to +ve and ground pins of the barrel jack and got a reading of 15V. Is there a chance (likely!) that I'm doing something wrong or misunderstanding something, or should I not trust this wall wart?

The circuit is a slide switch, a resistor and an LED.

Thanks


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YurkshireLad
(@yurkshirelad)
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I assume I need a 330mA load to get 9V.


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SuperCharlie
(@supercharlie)
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@yurkshirelad

I'm not the circuit guy but ya voltage drops on load.. not sure about 330mA dropping 6 volts tho..


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YurkshireLad
(@yurkshirelad)
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It says "9V 330mA", so who knows what miracles may occur! 😀 


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noweare
(@noweare)
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They are regulated so it should be 9v from no load to 330 ma. 


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magicChristian
(@magicchristian)
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If your power supply is not regulated and you have no load than it can happen that the output voltage is much higher than the nominal.  But try to have a load with p.e. 100 mA ( a power resistor with 100 Ohm and 2 W)  and check the voltage again.  One question is: did your LED get bright with the 14 V OUTPUT?


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YurkshireLad
(@yurkshirelad)
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The LED did get bright.


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