DC Power Supply

I was sent a power supply for a unit that requires 9 volts DC with

180ma. The power supply says input 220v AC, not 110-220v, so I guess that means non switching, and is supposed to supply 300ma of current. . I checked the voltage output and it is 9.5 volts, so I'm good with that, but I do not have an amprobe, so I couldn't check the current. Basically the power supply does not have enough "juice" to power the unit (a CCTV camera).

Here is the question. Since I can't check the amperage from the power supply, could the fact that I'm pluging it into 110v and not 220v be the reason that I am having a problem? What would the amperage output of the unit be? Is there a conversion formula? Is it half? It appears to be the situation. Thanks in advance.

Reply to
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Cheap power supplies often put out much more than their rated voltage, when they have no load. There is no way to determine what the voltage it's putting out with full load and 110V input is, except to test it. There are too many variables. You could guess "half the rated voltage" but you'd probably be wrong.

9VDC power supplies cost what, $10 if that? Go to Radio Shack, or
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and buy the right one. Or buy a 110VAC to 220VAC step-up transformer if you're really attached to this particular power supply for some reason (such as an oddball power connector).
Reply to
Walter Harley

measure the voltage again with the camera attached (or use a 50 (or 47) ohm resistor) it'll probably be less than 9v under load.

a generic replacement powersupply should only cost a few dollars.

Bye. Jasen

Reply to
Jasen Betts

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