best way to measure current?

Jun 29, 2009 1 Replies

I have a coil. I want to accurately measure the amount of energy/current that it uses when pulsed with one single square wave. I know I can take a voltage and current measurement and multiply them together to get a wattage. is that the only way? is there such as thing as a wattmeter? that just simply tells me how much energy was just used? I guess its a stupid question.



a side question - if I set my power supply to "constant current mode" (say at .3A) and at 12V the most my coil can draw is 3.6 Watts correct? so this would happen when I simply short the power supply with my coil.


Not a stupid question. In fact, it is a very involved problem in AC measurement. One needs to consider the phase of the current and voltage. Google "AC current" and phase. The current through, and voltage across an inductance (and a coil has a LOT of inductance) occur at different points in the cycle. So the determination of power in an AC cicuit containing a big inductor or capacitor is not a trivial problem.

And pulsed power IS AC. There are simple power meters (wattmeters) and complex ones. The later, which do what you want, are not cheap.

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