On 12/17/2010 01:32 PM, Harvey Norris wrote:
> [...] Unfortunately the choice
>  of a neon bulb may not satisfy that criteria, so the circuits are being 
> re-engineered to show ferrite incandescence as a load.

Depends on whether you're just trying to fool people, or actually trying
to measure something.

If you're trying to measure something, a static load -- like a big power
resistor -- and a power meter measuring how much it's actually consuming
would be a plausible choice.  If you don't have a power meter, a simple
resistive load with a digital scope across it would be a reasonable
first step, with current computed from the voltage and resistance.

Of course you need something equivalent at the front end, so you
actually know, for sure, how much power's really being drawn from your
power supply -- in short, you need measured power in, and measured power
out.  (Power, not just voltage.)  And, of course, you need to measure
the drain at the supply, not at some intermediate point in the circuit;
otherwise cute effects like inductive coupling may be overlooked.

Once you've got real power measurements of some sort which show
something interesting, then you can start wondering about making more
*precise* measurements and seeing if the effect holds up.

And once you've got actual power numbers, showing total power drawn from
your supply is less than power going into the load, then watching your
videos will be an interesting exercise.

But lighting a lightbulb or just measuring voltages is kind of useless
for showing anything about power out versus power in.  In short, it
shows *nothing* -- it's like Newman's trick of showing his motor could
pump water, but never saying how much power that required.  It's, like,
so what?

(I guess, really, all I've done is echo what Fran said, using more words.)

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