simple design thermal wattmeter ?

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Dimbulb
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simple design thermal wattmeter ?

Post by Dimbulb » Sun Jun 19, 2011 9:16 am

Hi, I need your help for a design of a thermal wattmeter.
It is needed to measure output power of complex waveforms.
such as dc pulse, trapazoid, and variants

while most of the oscillators are
typically 1 inch (49mm) toroid coupled to negative resistor
some do do not use NR as load.

The the insertion of the wattmeter into circuit
while minimizing alteration of the waveform.

Someone suggested using a resistor as load.

I am wondering if a simple analog RF mW meter might work ?

The target project is for mid to experienced builder.

Thankyou

Robert Reed
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Re: simple design thermal wattmeter ?

Post by Robert Reed » Sun Jun 19, 2011 9:02 pm

Have only had limited experience with RF mw meters. Most used a DC voltmeter as the readout and were committed to reading steady state sine waves above 1 MHz. Internal circuitry converted to RMS and computed wattage by ohms law then to the panel voltmeter which was read in watts. If your wave shapes are repetitive and not highly complex, there are simple formulas for conversion to RMS voltage. Then when reading your wave shape voltage across a known resistance, use the conversion formula for RMS value, followed by simple ohms law for wattage. With this value you can compute wattage over a huge range (i.e. uW,mW, Watts).

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Bob Scott
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Re: simple design thermal wattmeter ?

Post by Bob Scott » Mon Jun 20, 2011 11:30 am

Dimbulb:

You didn't say what frequency range your signals are.(?)
What is a THERMAL wattmeter? Do you measure the temperature rise in a resistor?

If you have a resistive load, you can just change the scale of a voltmeter. P = V^2 / R.

If you are driving a load with reactances, the current will be out of phase with the voltage, so you should measure both the voltage and the current independently, then multiply the two waveforms together with an analog multiplier IC like TI's MPY634. P = I*R. (if your signal is less than the high frequency limit of the IC.)

The multiplier IC's output is proportional to both input signals. You can probably make your own basic multiplier by having the voltage signal pulse-width-modulated by the current signal. Again, the output voltage will be proportional to both input signal voltages.

Or...you can digitize the signals with A-D converters and have a microprocessor figure it out.
-=VA7KOR=- My solar system includes Pluto.

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Re: simple design thermal wattmeter ?

Post by Robert Reed » Mon Jun 20, 2011 9:29 pm

"If you have a resistive load, you can just change the scale of a voltmeter. P = V^2 / R."

This will only work for DC. For AC you first have to convert to RMS. The conversion formula will be different for each type of wave form. Not always the common 0.707 ratio that we use for sine waves only.

Dimbulb
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Re: simple design thermal wattmeter ?

Post by Dimbulb » Tue Jun 21, 2011 2:43 am

Maybe I should start over, maybe thermal watt meter is'nt what a replicator needs.

For a frequency I see the author Steven Jones tektronix 3032
ch1 3.926 Mhz ch2 37.1 Mhz

scope shots
http://pesn.com/2011/05/27/9501835_Stev ... l_redu.jpg

Its not that the Steven Jones needs to understand anything with due respect.

It is more of how others can verify and progress this using what they have.
I think it could be a popular thread if you guys want.
I see a need for the basic electronics help from a nuts and volts aspect.
You have really helped me over the years.
there is also a contest brewing on this.

article brief
http://pesn.com/2011/05/27/9501835_Stev ... y_circuit/

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jwax
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Re: simple design thermal wattmeter ?

Post by jwax » Tue Jun 21, 2011 6:52 am

If the contest is whether "overunity" power is produced, I know where my money would be.
Never, repeat never been demonstrated, even theoretically.

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Re: simple design thermal wattmeter ?

Post by Robert Reed » Tue Jun 21, 2011 9:18 am

The energy you want to measure has very complex wave forms and my prior posts would be of no use in this situation. Certainly a thermal device which measures actual heat of dissipated electrical energy is called for here. These are used in HF to UHF frequency spectrums. They will measure low power levels and come in several flavors, such as bolometer bridge,etc. These are super expensive devices and not for even the expert hobbiest to attempt to construct.
I am very skeptical of devices that produce more power out than power in. Sorta' goes against the laws of physics, but not being a physicist myself, I have to respect their opinions until proven false.

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Re: simple design thermal wattmeter ?

Post by Dimbulb » Tue Jun 21, 2011 5:28 pm

Thankyou Robert,
The bolometer idea is helpful, there are so many. The compensated thermistor bridge looks
promising while other types are possibly too sensitive, the radar type would need some scaling some are
very elaborate and expensive at first look it seems complex.

I am wondering if an RF type power meters like used to tune QRP mW meter.

Jwax, I understand that when it comes to survival that you are packed.
The truth is what were after, he does'nt like scams or nonsense.
He understands metals (ferrite). Jones investigated the 911 shape charge.

There are several replications confirming Jones, we're not sure about the
power measurment equipment and that is why I am asking for good advise.
Does'nt matter if you believe in it, the post is about watt meter and instrumentation.
unfortuneatly I had to post links because we could'nt play guessing games
about the needs of this watt meter.

The guys with the contest want to see whose joule thief
runs an led the longest I think one of them we know here.
I think the people wanting to understand this would
run far away from nuts and volts on strong opinions.

one example of ou is photovoltaics.

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Re: simple design thermal wattmeter ?

Post by dyarker » Tue Jun 21, 2011 11:41 pm

article brief
http://pesn.com/2011/05/27/9501835_Stev ... y_circuit/
Read it through a couple times.

Cold fusion professor - 1 BS point.

Multiple mentions of o'scope model number trying to impress. It not the o'scope it's the user. 2nd BS point.

No mention in article of where o'scope channels were connected on schematic of circuit. Sweep speed of o'scope too low. Any time an inductor is involved there WILL BE a phase shift. Just multiplying RMS values WILL give wildly erroneous results. 3rd BS point.

Article carefully written to avoid giving facts. more BS

The circuit may be a very efficient LED driver, but it is NOT over unity. An analogy would be driving a low voltage load from 120VAC with a dropping capacitor instead of a dropping resistor. It is simply taking advantage of the voltage/current phase shift versus making a lot of heat.

Cheers,
Dale Y

Dimbulb
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Re: simple design thermal wattmeter ?

Post by Dimbulb » Wed Jun 22, 2011 1:28 am

to dyarker

The reporter stirling allan may not understand all the technical
electronic and physics details, for example it's not cold fusion but muon-catalyzed fusion
same difference. a simple search no bs
http://en.wikipedia.org/wiki/Steven_E._Jones

The scope connection points are in the video taken at replicators house.
there is extensive documentation on pdf

I would'nt be too quick at putting the man down

can we get back to finding a good method of measuring
the power output instead of jumping all over this guy.

you feel multiplying is erroneous, ok
how do we find the real output.

forget about what the circuit is for and focus on
how to find truth. otherwise it's just nay sayer venting !

dyarker
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Re: simple design thermal wattmeter ?

Post by dyarker » Wed Jun 22, 2011 6:45 am

Not putting him down ... he'd probably make a good used car salesman too!

There is no such thing as over unity, aka perpetual motion, etc.

All that is happening is the LED flashes very brightly in short pulses at a fast rate. It is off most of the time. That is a lot less power than continuously on at the nearly the same apparent brightness. So yes, the batteries last longer; but there is not more power out than in from batteries. Period. And, I did give credit for an efficient circuit.

Simple multiplication is okay for DC or resistive loaded AC. With pulses, and especially with reactive circuits, true power is hard calculate.

If you want to believe in the tooth fairy, go for it. Bye.
Dale Y

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Bob Scott
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Re: simple design thermal wattmeter ?

Post by Bob Scott » Wed Jun 22, 2011 11:31 am

Dimbulb wrote:I would'nt be too quick at putting the man down

can we get back to finding a good method of measuring
the power output instead of jumping all over this guy.

you feel multiplying is erroneous, ok
how do we find the real output.

forget about what the circuit is for and focus on
how to find truth. otherwise it's just nay sayer venting !
Dimbulb, it is no wonder that BYU suspended him from his position. As a PROFESSOR he knows well enough that he has to support his claims with facts. He has to do his math and show his math, the same as he expects from any work by his students. It is not up to us to disprove his wild theory that a "Joule thief" is an over unity device. Exactly how do the energy figures not add up? Which part is responsible for injecting extra energy? He has to prove it first before he makes a claim. Did he indeed make this rediculous claim?
-=VA7KOR=- My solar system includes Pluto.

Dimbulb
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Re: simple design thermal wattmeter ?

Post by Dimbulb » Wed Jun 22, 2011 1:46 pm

Dyarker, its all good, sometimes we have to be pointed in our post.

To Bob Scott,
He says according to the BYU fancy state of the art oscilloscope tektronics 3032
it integrated the area under the wave and it says the power is 7.9 times the input.

Also there is report that the stinking fancy oscilloscope at the university Hong Kong
has an entire team going on this as well because the oscilliscope says.

Nobody wants to say "I think something is wrong with the digital oscillosope technology
for measuring power on complex narrow DC pulse"

From your comments it's starting to add up that leds and fancy oscilloscopes don't prove
anything ! A faint glow in an led is not a good watt meter but is better than a tektronix 3032

As far as Jones being a car salesman. No, he is doing it open source.

I try to be objective, need to admonish and be respectful to the prof.

however you make a good point, do you mind showing us your math, professor.

I will be emailing him on this and his claim is not substantiated.
I don't know what kind of watt meter he needs but turning down
the power on the led makes it more difficult, a bolometer was the best idea so far.

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jwax
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Re: simple design thermal wattmeter ?

Post by jwax » Thu Jun 23, 2011 3:47 am

Put the "overunity" circuit in a well-insulated box and watch the internal temperature rise- indefinitely.

Dimbulb
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Re: simple design thermal wattmeter ?

Post by Dimbulb » Thu Jun 23, 2011 6:50 pm

my latest
epoxy an LM35 on the output measuring resistor
using temp on pure resistive load and reliable power source.

input with constant voltage constant current ex:5V @ 10mA
directly to the resistor with lm35 so the temp is over ambient.
now insert the joule thief and see if the heat rises significantly.

the voltage of this type pulse does'nt measure correctly
on most digital multimeters and led is not a pure resistive load.

the approximation of light in leds as an indicator has been exploited
by videos using low lighted rooms and cameras that pick up leds well.

there must be over 1000 youtube videos showing leds this way.
the days of simple sine and rms approximation has changed.
The pulse technology commonly used today however electronic
text books are not up to date and do not mention these facts clearly.

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