Accurate Measurements on pulsed system's harder than you think.

[verpies]

If on the same pulsed circuit, my scope shows  for example  :  on Chanel 1, an average (mean)  voltage of 10 volts and on channel 2, an average (mean) current of 2 A, can i simply assume that the average (mean) power is the multiplication of these 2 average (mean) values, and in this case,  the  MEAN POWER of the pulse  is  10  x 2 = 20 watts ? yes or not ?

Not.
You can assume that only for pure DC.

P.S.
Do you have MS-Excel?

[EMJunkie]

@Brad and All

EXCELLENT Demonstration!!!

EVERYONE should watch this and pay very close attention!

Faradays Law of Induction clearly Assists the action in this System!!!

   Chris Sykes
       hyiq.org

Normal Faradays Law of Induction principals apply, for Improvements:

Increasing the Cross Sectional Area of the Coils and Magnets
Increasing the Turns, but not too much...
Increasing the Time Rate of Change (The Frequency)

Back in the day, the Bedini h was pointed out many times... I think many did not see the link?

Any Magnetic Field changing in time is a potential source for Faradays Law of Induction!!!

   Chris Sykes
       hyiq.org

[woopy]

Not.
You can assume that only for pure DC.

P.S.
Do you have MS-Excel?

Thank's Verpies

very clear answer

So if i understand you well, i can not use my scope to measure average pulsed power input.

I think the title of this thread is even much harder than Tinman suggested.

1-So why are the scope constructors offers the possibility to get  the average voltage of pulsed power if there are not usable ?

2-So have you a good and "simple " way  to measure those pulsed average input power with some accuracy ?

finally yes i have MS excel

Laurent

[EMJunkie]

Because mathematically:  AVERAGE(i₁, i₂) * AVERAGE(v₁, v₂) <> AVERAGE(i₁*v₁, i₂*v₂).
Take a calculator or a spreadsheet and see for yourself.

Thanks Verpies and TK I did not know this! It makes sense! The more averaging over time the more precise the figure would be.

I am happy to put a small program together with all of these little tips and tricks in it if you guys are happy to scrutinise it and test it? This way it can help everyone with their work get an accurate result!

Are you guys keen to participate in this?

   Chris Sykes
       hyiq.org

[verpies]

So if i understand you well, i can not use my scope to measure average pulsed power input.

Yes, you can ...by multiplying two traces just like TinselKoala did in these scopeshots.

1-So why are the scope constructors offers the possibility to get  the average voltage of pulsed power if there are not usable ?

Because average voltage still might be useful for other purposes besides power calculation.

2-So have you a good and "simple " way  to measure those pulsed average input power with some accuracy ?

If the current is not in phase with voltage then there is not a simple way.
If the current is in phase with voltage then the i&v averages can be multiplied with some scaling.