PDA

View Full Version : Amperage Measurement


seeker
06-23-08, 08:48 PM
I know of calculators that can tell you what the amperage load should be on a PS rail, but is there any way to measure what it actually is?

CaptNKILL
06-23-08, 08:55 PM
With a digital multimeter or ammeter. I don't think there is any way to measure things like that in software.

seeker
06-23-08, 09:03 PM
I think that you are right about measuring with the PC or software, and I know how to measure an individual circuit, but how would one connnect a DVM in such a way to measure the overall output on a particular rail? If that could be done, it would seem that it would be necessary to do so inside the PS, and that would be impractical and risky with the PC running.

CaptNKILL
06-23-08, 09:27 PM
You'll probably want to do a google search for something like that. When you're dealing with possibly electrocuting yourself or frying your components you'll want a reliable source of information.

einstein_314
06-23-08, 10:53 PM
To measure current, you need to connect an ammeter in series with the rail. ie, all the power on the rail must flow through the ammeter. Not possible to do in a powersupply with out chopping it and risking a huuuuge shock. There are ammeters that you can get that just clamp around the wires and measure current using the magnetic field generated by the current, but they are expensive. And I don't know how they would work on a bunch of wires. Might confuse it.

BCKator
06-24-08, 03:28 AM
To measure current, you need to connect an ammeter in series with the rail. ie, all the power on the rail must flow through the ammeter. Not possible to do in a powersupply with out chopping it and risking a huuuuge shock. There are ammeters that you can get that just clamp around the wires and measure current using the magnetic field generated by the current, but they are expensive. And I don't know how they would work on a bunch of wires. Might confuse it.

I agree w/ the above. The clamp on meter should work if you put it around one wire at a time or just the +v or just the GNDs (but not both at the same time). If you don't want to buy a clamp-on meter, you could cut each wire and put the meter in series. Most are typically only rated up to 10A, but you should see more than 2A I would imagine in any single wire. You can get a Power Angel and it will tell you how much you are drawing on the AC inputs line. But this just tells you how much the entire system is consuming, not just, for example, one rail. DO NOT probe inside a live PCU and you must even be careful after its off.