Electric OU: Energy Flux Measurement Using the Digital Oscilloscope

Math on stored traces with the LeCroy digital storage oscilloscope.

Ainslie circuit with "bullitt1" load and Aaron's 555 clock in "normal" (not oscillation) mode.

Sorry it's so blurry. When I made this I could read the numbers even on the camera's tiny monitor. Something seems to have been lost in the conversions.

But hopefully you can get the idea. With proper programming even a partially functioning DSO can do a reasonable job of energy computation, on stored traces. Even in realtime if one is allowed to use a typical voltage trace held in storage for the computation. And of course with both input channels working the whole thing can be done in real time. (With stored traces you have to be very careful about trigger points and where the trace computations start and stop.)

I say, as always, one or two stupid things in here.
I'm sure viewers will be "kind" enough to point them out, and as I find them I'll put annotations in.
So don't just watch once!!

It takes several viewings for the subliminal programming to sink in:
Every day in every way I am getting more and more skeptical...

BY THE WAY: I hooked up a Large inductive load--an electromagnet of nearly 2 Henrys--and there was such spikyness that I could hear it singing and I actually got a pretty good shock. I didn't measure it but several hundred volts anyway.

And if you like spikes...try the 2sk1548 mosfet instead of the irfpg50. And/or driving the circuit with a fast risetime pulser rather than the 555 or a FG. You'll get better spikes. I forbid Aaron to try this, though.

Category:

Science & Technology

Tags:

• digital
• scope
• oscilloscope
• energy
• flow
• ainslie
• jesus
• ufo
• chocolate
• cake

[aetherevarising]

TK I've been trying to speak to this problem - and to the point shown in your video OU6 'What a good..." There's not enough space in these comment boxes. Can you contact me on gmail - aetherevarising? Please.

[janne808]

The correct power waveform pops out from the discrete numerical operation yes.

Phasor method is a powerful mathematical tool which simplifies the situation so that you don't have to deal with differential equations when analyzing circuits with time-dependant LC components and their impedances. Not very useful in non-linear situations like in these sort of pulsed circuits though but it gets you the frequency domain behaviour of the linear components from quick back of the envelope calculations.

[TinselKoala]

Oh, I see what you mean.

Fortunately I don't have to calculate anything like that. I think as long as the math is done on the actual synchronous current and voltage waveforms the phase angle takes care of itself and the true power and energy can be known. The problems arise when a power measurement depends on the rms values of I and V taken from some kind of meter, where the phase relationship isn't preserved in the original measurement and needs to be supplied by hand in a power computation.

[TinselKoala]

Yerp.

I mean, real integration isn't a problem.

I mean sure it's a problem but it's an analytic one and solveable analytically.

When it becomes a problem problem is when a numerical method is developed independently by someone with no knowledge of calculus and using only 4 or 5 samples per cycle of a complicated waveform an attempt is made to account for the energy flux in the circuit, and in addition perhaps the wrong numbers went into the calculation in the first place...that's a problem.

[janne808]

I meant the energy integration obviously. The power waveform is a simple multiply operation.

[janne808]

You can verify the power integration yourself with matlab/octave.

[janne808]

It's a little hazy half-baked term isn't it. Meaning here that the time-dependant wave equation gets you complex number values where phase has a similar meaning than here due to the impedance phasors.

[TinselKoala]

Moi?

I'm sorry, but I really don't deal with imaginary-time quantum mechanics.

I have enough trouble with real-time mechanics. Even if they don't leave their tools in the driveway.

[TinselKoala]

Check your assumptions. Your math is OK but you are mixing apples (the power dissipated in the SHUNT is 640 milliWatts) with oranges (the power dissipated in the LOAD is 40 or 20 watts).

And we really don't care about the current in the inductor, and the only capacitor is the interlead and transistor junction capacitances. And since the scope is supposed to measure the current and voltage input WAVEFORMs for the math functions, the phase differences if any are fully accounted for. I think.

[TinselKoala]

And of course you are mixing up the power dissipated in the Current Viewing Shunt (0.25 ohms, 0.400 volts DROP), or 0.64 watts dissipated in the shunt. The 40 or 20 watt figure is for power dissipated in the 8.4 ohm LOAD at 1.6 Amps continuous or at 50 percent or so. Which can be calculated from the current of 1.6 amps and the battery voltage of 25 or so volts and the duty cycle of 40 percent ON.

And you really should read the Ainslie papers before we can seriously discuss resonance.