Reasonably accurate ATX power draw

[WeekendWarrior]

I would like to measure the power through an ATX connector within 1-2% accuracy from 1W to 100W. Inexpensive is good but not an absolute requirement.

Can anyone recommend a way to do this other than constructing my own jig using a shunt resistor?

For reasons that are somewhat detailed I want to measure the power at the ATX connector rather than the 120V line.

Thanks in advance for any assistance --
Dave

 

[Chuckleb]

Not exactly all the lines, this one can do video cards and CPU

::: Zalman, leading the world of Quiet Computing Solutions :::

 

[WeekendWarrior]

Thanks @Chuckleb for this suggestion, but Zalman says that it is not usable below 10W. I hope to measure power at or below 1W unless nothing economical can do that.

 

[John]

Just measure the voltage and current inline DMM or amp clamp. Calculate for power.

 

[Marsh]

A Fluke Meter
http://www.amazon.com/Fluke-115-Compact-True-RMS-Multimeter/dp/B000OCFFMW

 

[John]

Don't even need a Fluke. Requirements are 1-2% F.S. of 100W. Can hit those with free DMM from Harbor Freight

 

[Marsh]

within 1-2% accuracy from 1W to 100W

1% of 1W is 0.01 watt
0.01 watt / 5 volt is 0.002 Amp or 2 Milliamp

In this case , a fluke meter is cheap investment.

 

[John]

1-2% Accuracy of Full scale so +/- 1 Watt so you would be in the hundredths of an ohm. Once you're in the milliohms you're going to need to shell out some cash.

 

[WeekendWarrior]

Thanks for everyone's comments - they are helpful.

 

[Deslok]

Don't even need a Fluke. Requirements are 1-2% F.S. of 100W. Can hit those with free DMM from Harbor Freight

I'll second the DMM from harbor freight although i'm more inclined towards this one i've had it for years and use the probe to spot check case temps(and server room temp) regularly, granted i've got several of the free ones too, mostly so people don't walk off with the nice one.
14 Function Professional Digital Multimeter with Sound Level and Luminosity