Re: Intensity and what else affects a single ligth beam's temperature?

On Aug 6, 9:44 am, bz <bz+...@xxxxxxxxxxxxxxxxxxxx> wrote:
[...]

<< NO! This works with ANY component, resistive or reactive. >>

Then what was your result for the real power in 0.010 ohms
in series with 22uf driven by 120VAC 60 Hz ?

1.651e-4 W

165 microwatts?

You might say that. 165.089 uW, if you like.

The integral of the formula for inst voltage times inst current as
previously shown, from 0 to 1/60 sec.

I had previously said it was 0.304 W.
I was integrating from 0 to (2 pi)/60
seconds. That was an error on my part.

That sounds like you computing watt seconds
either way, instead of watts.

No. The limits of integration are expressed in time because the expression
being integrated is p(t) dt where p(t) is the power at any instant of time

p(t) = Vp sin(w t)(Vp/sqrt(R^2+(1/(w C)^2)) sin(w t + phi)

The derivation of which was previously explained.

The load is about 1/3 metre of 1mm dia (20 AWG) wire.
So it might really be as low as 165 microwatts.

I have been assuming that the 0.01 Ohms is non inductive. If you want an
inductor included in the circuit, you will need to provide the inductance.

At 60 Hz the inductive reactance is zero,


Can you change the resistor to 120 ohms and
confirm the power isn't some rounding error
stacking up.

Resistor of 120 ohms shifts the average power upward considerably. It is now
0.995 W

Power peaks at about 144.3665 W at 9.36554e-3 s
When the current is 0.941 A and the voltage is 156.71 V
Somewhere around 7.297E-3 seconds, the power peaks in the negative direction
at around -24.9 watts.


Hmmm...

<< True Power (P):
Power driven into a purely resistive load.
As we said before, its unit of measure is the
watt. This is the power dissipated in a purely
resistive load or the resistive part of a circuit
with both resistive (real) and reactive (imaginary)
components.
P = E²/R
P = I²R
P = I * E

http://www.bcae1.com/compleximpedance.htm

I get
P = 3600 / 120 ohms
P = 30 watts

Is the difference an "urban legand" :o)
We'll have to build a calorimeter if
you say it is.




We had numbers like 10 watts and 100 watts
previously. That is easily tested by comparing
the temperature of the 1mm wire with a resistor
disipatiing 10 watts. The right finger rule.

"If you can't hold your right finger on it for
10 seconds, it is 10 watts or better."
--Herbert Dingle ?

I was going to build it if you said 10 or 100 watts
again. But now your result is at the other extreme
and I might have to borrow some lab's squid
to detect 165 microwatts. :o)

Here is why that looks wrong.
(cheating and accessing a resistor
that motor users can't reach)

Peak current from wiki scope = 2 amps
RMS current = 0.707 amps

2 A / sqrt(2) = 1.414 A (RMS from peak) [did you mean 'peak to peak' ?]

Peak is from the x = 0 to the crest OR valley of the
sine wave.

Peak-to-Peak is from the crest TO the valley of
the sine wave.



http://campus.murraystate.edu/tsm/tsm118/Ch6/Ch6_3/ch6_3.htm

P = (0.707amps)^2 x 0.010 ohms
P = 5 millwatts

The current peaks at around 1 amp according to my calculations or .707 RMS.
This does NOT happen at the same time as the voltage or power peaks.

It should happen about -44.998 degrees from the
voltage peak. Recall that power is at 120 hz.
Half 90 degress ~44.998 degrees


5 milliwatts is 30 times your result,
165 microwatts.

I will recheck my calculations, using a couple of other math programs.
[note, these are some of my favorite math programs:]
I like Derive (old dos version but it is nice for symbolic math and infinite
precision math)
Mercury (old dos version, but it does iterative solutions rather nicely)
Mathematica, nice symbolic etc.
Mathcad, very good for handling units, factor label calculations. Automatic
unit conversion is very nice.
That is where I do most of my calculations. It does symbolic math using Maple
as a symbolic math engine.
Does number crunching rather well.

Maple is nice for symbolic work.
Matlab. Good for programming and heavy number crunching
Excel is very good for some kinds of work.
Tablecurve is good for finding the best equation to fit to data points.
Peakfit is good for deconvolution data.
[end note]

Not a factor or 2 or 4 that we could look at
our peaks and peak-to-peaks or our 1.4
and 1/1.4 and find a simple math error.

Your result went the right way, but I think
you over-shot the mark by a factor of
30. I wouldn't bet 807s or 1625s on it 'tho
because I know it is a very low value.

If I set the integration limits wrong, the number of intervals being included
in the summation will be wrong and that can throw off the final summation.. I
will do some cross checking.

http://home.att.net/~wa5cmi/images/arc5_23.jpg

If you are planning to edit a wiki page, I'll
see what I have out in the tool shed to
test your concepts. The calorimeter and
abacus is not easy to fool.

We have some equipment in one of the labs for measuring changes in a sample
as the temperature is run up. They measure heat flow into and out of very
small samples. I forget what it is called.

When you think it is right, you might post
to sci.physics.research for some review.
The regulars there have chalk dust where
we have cobwebs. :o)

:)

I found a Ouji board in the tool shed that might work
for banishing urban legands and a thermocouple that
indicates zero amps under all conditions.
But I am still digging for something more conventional.

Sue...


.

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