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

[TinselKoala]

TK
Try an inductor with a core.
I think the results will be better and more evident.

P.S--forgot to ask--no power measurements mentioned on the video?.

Brad

I'm not sure we are actually measuring any true power values yet.

In your original circuit, and my no-Bedini modification, the CH1 voltage drop across the bulb doesn't represent the input voltage to the circuit. The CH2 current is the input current, certainly, and actually the CH1 voltage drop across the bulb must also represent the input current and because of that we could calculate the resistance of the bulb.

That is, if the input current from the one-ohm CVR is, say, 94 mA (because we have  94 mV drop across 1 ohm), and we have 3.4 V_drop across the bulb, then since both are obviously carrying the same current, we have R = V/I  so R_bulb= 3.4V/0.094 A = 36.2 Ohms. 

So maybe now we can get the power dissipation in the bulb at that current, since Watts=I²R. So we have for example W = 36.2 x (0.098)² = 0.347 Watt being dissipated in the bulb. This is with capacitor connected in my circuit.

With cap disconnected and using the "average" values and going through the same calculations, we have average I = 62 mA and average Vdrop = 2.06 V, so the bulb's average resistance is V/I or 2.06/0.062 = 33.2 Ohms. So the average power dissipated in the bulb is 33.2 x (0.062)² = 0.127 Watt.

What is the conclusion we can draw from this, since the bulb is obviously brighter when the cap is disconnected? Perhaps:  Using the "average" values in the way we have been doing is not correct in the case of pulses through a bulb; OR perhaps: Our assumption about the relationship between the bulb's brightness and the "average" power _in the pulses_ is not correct. Or both.

Or maybe my math is just totally screwed.

As far as the inductor goes... it is not necessary to produce the effect. I have eliminated the inductor entirely, along with the long leads I used to connect it, and I've simply placed a 34 Ohm resistor directly on my little breadboard between the bulb and the mosfet Drain, and the effect still happens just as before. There is less spikeyness when the cap is connected but the bulb dims while the "average" current through it goes up, just as before.

[TinselKoala]

EMJ
This is where incorrect assumptions start,and i hope you either remove this claim,or correct it.
If you listen to the video,and watch the video carefully,then you will know that i have dropped the channel down 1 division so as to fit the whole wave form in the scopes screen.
So the mean value given is correct,and your red voltage calculation you added to the scope shot is incorrect.


Brad

Ah, that's right. EMJ is measuring from the horizontal center graticule line, and your baseline is one division below that, so your mean values are indeed correct, and not thrown off by spikes or whatnot.

In the (nearly) full shot below we can see on the left edge where the channel baselines are positioned. They are both one full division below the centerline. The yellow marker at the screen centerline is the Trigger level marker, isn't it?

[EMJunkie]

Ah, that's right. EMJ is measuring from the horizontal center graticule line, and your baseline is one division below that, so your mean values are indeed correct, and not thrown off by spikes or whatnot.

In the (nearly) full shot below we can see on the left edge where the channel baselines are positioned. They are both one full division below the centerline. The yellow marker at the screen centerline is the Trigger level marker, isn't it?

I don't believe this is correct, yellow channel baseline is pretty much on the horizontal center graticule line: See Image

Blue Channel Baseline is 1div below the horizontal center graticule line.

Correct me if you have changed the value of this baseline Brad.

    Chris Sykes
       hyiq.org

[TinselKoala]

No, both channel baselines are one division below centerline. The Blue channel marker is overlaying the Yellow channel marker so you can't see it, and the yellow marker you do see is the Trigger level indicator, indicating Trigger on CH1 (because it is yellow) and at approx. 2 Volts above the baseline,which puts it just a hair below the screen centerline marker. (See the exact trigger level on the bottom right of the screenshot I've posted.)

[tinman]

I don't believe this is correct, yellow channel baseline is pretty much on the horizontal center graticule line: See Image

Blue Channel Baseline is 1div below the horizontal center graticule line.

Correct me if you have changed the value of this baseline Brad.

    Chris Sykes
       hyiq.org

No-the yellow marker for channel 1 is being hidden by the blue marker of channel 2. The yellow marker you see at the base line is the trigger marker,and it is yellow because i am triggering on channel 1. If i was triggering on channel 2,then that marker on the base line would be blue.


Brad