Carlos E. R. wrote:
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The Friday 2008-02-15 at 16:07 +0100, Per Jessen wrote:
I would look for a device with a needle rather than a digital readout.
I don't think you can measure true rms with a coil and needle. :-? It was measured by thermal effects...
Carlos, Aaron only said "readout", which is unrelated to how it is measured. The advantage of an analog readout over a digital is that it is possible for a human to see spikes/changes more clearly.
I know that. I've always liked analog multimeters for that reason.
But I don't think you can get a needle movement with rms voltage measurement. And the amp meter "tweezers" I have used did certainly work badly with triac controlled motors and PC power supplies. So allow me some doubt that a needle thing could measure ac power properly nowdays.
Not so much for "accurate" reading but looking for fluctuations, which are much easier to make sense of with a needle than with a digital readout.
Your gadget is probably using a new chip that made the market probably recently designed for the purpose of power measurement with complex waveform. I wonder if power distributors are thinking on using such chips on house meters instead of the mechanic meters they use now.
I doubt it. The current meters measure total power (real power + imaginary power). Since the generators see both the real power and the imaginary power, it is in everyone's best interest that power continue to be metered using the current method which bills for both real and imaginary power. [Because of this, appliance manufacturers, especially electric motor manufacturers, are motivated to design things so that imaginary power is kept to a minimum]. Real power is current which is in phase with the supply voltage. Imaginary power is current which is out of phase with the supply voltage. -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org