Joule Thief

[xee2]

@ jeanna

Nice looking charts. Are all of the voltages measured between the two pickup coil leads? If not, can you explain where the voltages were measured.

[Pirate88179]

@ Jeanna:

What Jim is now describing is what I meant in my earlier post about the 3055 transistor needing more juice to turn on.  I have nothing against the 3055, i am using several of them as we speak, I just was pointing out the additional power needed.

Bill

[electricme]

@All,
I just finished a reply, it took me about an hour, to all those who have helped me today, and I went to preview, then it siezed up, I could not post the reply, and I ended up loosing it,

Then when the RED message appeared at the top of screen mentioning someone had made another post, and to take a look if I wanted to. But didn't.

I still could not post.

I saw a paperclip with a .jpg file so I clicked on this and was promply told I could not open it as it wasn't allowed.

@ Bill
Any chance of PMing Stefan, and ask him if he is aware of the probs some of us are having on this new forum he has updated to?
He probably is aware of it, but tied up with other stuff.

jim

[Pirate88179]

Jim:

You can turn off the alert when someone is posting at the same time you are if you want to.  I have mine turned off.  You can do this in the look and feel section on your profile if I remember correctly.  As for the paperclip, I have never seen that one.

Bill

[jeanna]

@ jeanna

I wish I had a scope. So maybe the decrease in current when the base capacitor is added is because the spikes get narrower. The narrower spikes would have less energy than the wide spikes and thus use less current. I was assuming the decrease in current was because there was a longer time between the spikes with the added capacitance. Any more data you can collect on this would be appreciated. Thanks for what you have done already.

This needs a reply, because the skinny spikes are often the ones without the cap and the broader more sinewave-like are the ones with the caps.

On some with the higher caps value, the wave is very wild. The scope cannot make it out at first and it looks like a coil gun wave. The so called ring. First tall then shorter and shorter etc. Ist showed one like this once. He was hand pulsing it with the battery, if you remember.

But this was happening with the cap 103 and 104 only. But the overall voltage and frequency if it was true, was quite low there. I suspect the scope just couldn't read it properly.

The other thing to mention is that I am seeing a pretty steady change in volts and amps draw. and, there is no surprise with the amps draw on the BJTL spot. the light goes really dim when the amps draw is low.

As always, the surprise is found on the secondary. The light off the secondary was not blazing but very bright no matter what the cap size was. And you will notice that the amps draw did increase when I had the light running off that secondary.-- by about 10mA.

The only place where there was trhe same brightness led running off the secondary and very little amps draw, was on the bottom 2 rows of the 2200ohm group. With the 103 and 104 and with the led across the secondary, the amps draw was only 2.6 and 2.3mA.

The brightness of the light off the secondary is unchanged by the cap.
With or without a cap at the base of the transistor, it is still bright but about 1/3 as bright as in the BJTL spot with no cap.

So, it seems the cap will change the basic circuit, but the effect on the light being lit by the secondary is extremely small. Not visible.

I wish you had a scope too!

jeanna