Quote from: wattsup on July 11, 2009, 11:32:30 PM
@gotoluc

I also agree with @poynt99. If someone grabbed an image of the bulb each time you made a change and blew up the image and put them side by side, I am sure there will be some differences. At that low brightness level, a small change could easily mean 50% more or less and it would still be hard to make out the difference visually.

Also, during both video tests was the return diode on or off. This was not clear to me. It may have been good to switch it in and out to see the difference at each setting. But very good work.

Hi wattsup,

go ahead and grab a frame of each test since I'm quite positive the levels are all the same. I have been using this technique for over 6 months and I know how to keep the level the same. If you look at the bulbs barley glowing filament you will see a slightly darker spot always at the same spot. That is the right side filament support and I use it for fine tuning, one micro change and it starts to glow. I keep it just before that, so I'm sorry but I disagree with you on this one. It cannot be off by that amount. For beginners using this technique I would recommend to bring the bulb to the point you can just barely see a glow, since this is more accurate but one needs to find the right bulb to do this.

In both test 5 and 6 the diode is recirculating. I did not switch off because I have demonstrated that in the previous videos, it also takes up time and it is the recirculating diode effect that I'm studying.

@.99
Thanks for the advice.

@TK
Looking forward to see that demo

Luc

@gotoluc

Thanks for your reply.

I put in some overtime and grabbed each bulb image, saved them at 1200 dpi resolution, blew em up 3fold, then grabbed the whole thing to show. I also summarized your Video6?

This is just a small technicality and would never show any sign of major disparity between what you have shown and the results, etc. But when you say the bulb is the same intensity, you then have to show how the same they are. I could see it by eye but wanted to put it here. We can make our own judgments. The bulb was never as bright as when you put it on straight DC so that is already a winner. But academia will demand more precision even though the end result is obvious.

Hope this helps.

wattsup

Added:

I forgot to mention that these photos would not be possible if your handy cam work was not so precise at each test giving the same angle shot. I must say, the whole video was very well done. An example to all.

Hi everyone,

Rosemary was asking me about the circuit used in my test 4 video and I drew it by hand for her and though to also post it here if anyone is interested.

I also just saw her circuit today for the first time! not much difference ... the only difference is in her circuit the flyback is created by the small inductance of a heating element and in mine it is created by a much higher inductance coil.

Luc

WOW wattsup

that is a massive amount of work ... I never thought you would do it

Thank you so much for putting this together. I'm sure it will help for those how want to look and compare the results.

I'm also surprised to see the intensity is quite similar since none of the shots were done exactly at the same distance and would produce some differences. I can use a tripod if ever I do this again or better yet as TK has suggested a photo resistive cell and monitor the voltage output.

Anyways, thanks for doing such an amazing job and to think you used only the Youtube resolution.

Luc

Hi all,

I just found out that in fact there is a very large difference with my circuit and Rosemary's:



Originally Posted by SkyWatcher

Hi folks, Hi gotoluc, I did not realize that is the way you had the output resistor within circuit gotoluc. I was using Rosemary's circuit which does give more heat because I tried both ways although not sure if the coil field would reduce. Here is a cad pic of the circuit I've been using, which I believe is the same as Rosemary's circuit.


Hi SkyWatcher,

humm... you're right!... I see now there is a very big difference. In Rosemary's circuit the resistor causes resistance during the on pulse, which means it will be heated by the supply energy and then heated by the flyback when it switches off. In mine, I only wanted the flyback to go though the resistor.

Wow SkyWatcher, thanks for bringing my attention back to this since I thought that both circuits were the same.

If I were you I would think about this as you maybe getting more heat in Rosemary's circuit but if you think about it you are paying for it since it comes directly from the power supply during the on cycle.

I chose not to do that since flyback effects is what I've been studying.

Anyways, do what you think is best.

Luc