CPD mod - capacitor potentiometer diode modification

[min2oly]

i was wanting to be able to run my 8 transistor at 4 amps if possible and not have heat on the resistor that is paralleled to the cap... i believe we are both talking about the same resistor....(base resistor and everything else cool) sure it runs cooler just when it hits square wave and before square wave..... but when i push it with lower resistance(something i want to be able to do if im on a big battery... 0.5amps per tranny shoulld be possible in my opinion) that resistor gets hot.... i tried 3 10uf caps paralleled and it was resonating just under 4 amps... i stopped bypassing the diode and added the 100 ohm resistor in parallel with the cap and it still heated up.... yes aln with the 10uf cap for it to start to resonate i had to put fingers on both sides of the cap just to add some resistance so it would start to oscilate.... so pat is it possible to hit square wave then push it past(continue to lower resistance) so the square wave starts widening for insane charging without that resistor getting hot?

I get it, you WANT to drive it hard...
yes, that resistor is going to get hot.
I have used a light bulb in combination with that Cap resistor in the past or just the bulb, I wonder if that might help??????? try 12v bulbs to start - The ones I used a found in the auto section at the dollar store...

If you're interest is in charging the larger batteries and not so much in efficiency, you might think about using a 555 timer or an arduino for absolute control to drive the transistors.
Hope this helps - Patrick

[Brodie Gwilliam]

i was wanting to be able to run my 8 transistor at 4 amps if possible and not have heat on the resistor that is paralleled to the cap... i believe we are both talking about the same resistor....(base resistor and everything else cool) sure it runs cooler just when it hits square wave and before square wave..... but when i push it with lower resistance(something i want to be able to do if im on a big battery... 0.5amps per tranny shoulld be possible in my opinion) that resistor gets hot.... i tried 3 10uf caps paralleled and it was resonating just under 4 amps... i stopped bypassing the diode and added the 100 ohm resistor in parallel with the cap and it still heated up.... yes aln with the 10uf cap for it to start to resonate i had to put fingers on both sides of the cap just to add some resistance so it would start to oscilate.... so pat is it possible to hit square wave then push it past(continue to lower resistance) so the square wave starts widening for insane charging without that resistor getting hot?

[min2oly]

So I made enough time to try the experiment with a 1.5 uf and a 10 uf cap. I believe the coil didn't oscillate until I put a meter across the cap, then it went like crazy and heated the resistor as before. I tried this in gen mode and vanilla. I may have some component issues from overheating earlier. I will check them later as I will be away for a bit. So thanks Pat, reread this thread and watched the posted videos again, very helpful. will get the radio out when I get back to it. Al

Hi Al & Brodie,
Thanks for doing this perhaps I left something out in the explanation. This is good do get it out in the thread. It will show my flaws and we can fix so others can follow.

Heated the resistor? what resistor.... there should be no resistor across the cap if you are doing this.

Are you guys both talking about the resistors just before the bases of each transistor?
you are both working on multi-filers right?

So when you say the resistor is heating up you mean "resistors" plural?

or are you talking about the resistor across the cap because the experiment calls for removing that one...

Brodie, if I'm reading correctly between the lines (having to read your mind and guess exactly what you are doing I would say yes, you are getting there. Now that you are in the ball park you can add the resistances accordingly get to the same place Hz and pull back - you do not want the square wave, the square wave is wasting energy. It does charge nice though doesn't it :-)

KR - Patrick

[aln]

So I made enough time to try the experiment with a 1.5 uf and a 10 uf cap. I believe the coil didn't oscillate until I put a meter across the cap, then it went like crazy and heated the resistor as before. I tried this in gen mode and vanilla. I may have some component issues from overheating earlier. I will check them later as I will be away for a bit. So thanks Pat, reread this thread and watched the posted videos again, very helpful. will get the radio out when I get back to it. Al

[Brodie Gwilliam]

just paralleled 2 10uf caps and it shot up to a resonant point of about 3.5 amps... im guessing this is on the right track?

[Brodie Gwilliam]

so i tried some 1uf film capacitors and was still getting some heat... i got both the 1uf and the 10uf to resonate by bypassing the diode... 10uf ran at 2.2 amps(exact same amp draw as when the capicitor/resistor combo turns to square wave), and the 1uf about 1 amp... 1uf faster frequency as you would expect.... i feel like the 1uf was maybe a little less heat in the paralleled resistor when pushed to 4 amps, but was also in my opinion, not as nice of a squarewave.... the on time seemed longer.... any theories pat?

[aln]

Will do the experiment, watched the video when you posted and again last night. Thanks for taking the time to respond, I will take the time to do the work. Have no time for next 2 weeks except tonight so if I get to it tonight I will update otherwise it will be a bit. P.S. I changed my transistor last night because I had burnt it out and got out a mega ohm pot as well. Also accidently broke the arm of my yellow cap from r_charge (same as yours) and solder was not keeping it on, but I had a couple more sitting around so I'm still good on those. Al

[min2oly]

i dont have time to fiddle at the time being, but i was wondering if you could discuss what you did on your coil to reduce heat in resistor... i thought you had a similar coil and could just say the changes that need to be made.... i have 100 ohm resistor right before the bases on my coil and they stay cool, its just the 100 ohm and or rheostat parallell'd to the yellow 10uf capacitor that heat up.... ive made a couple of these back in the day with different coils and smaller capacitors and such, but whenever i push em into the square wave and beyond i find heat starts to come out in that resistor....

So anyone running into this same situation, just spend a few minutes watching the video then do it on your own coil and you will have your answer. If I come right out and say it, the numbers will be wrong for your particular coil anyway so I would not be helping. It really is very simple.

Let me know if you run into any problems, you do not have to desolder anything just use jumpers... it should only take a few minutes, quicker than this exchange for sure.

fyi - I pretty much spell it out in the vid. you do not have to figure out why the heat is there, just follow my example and it will not be there.

KR - Patrick

[Brodie Gwilliam]

i dont have time to fiddle at the time being, but i was wondering if you could discuss what you did on your coil to reduce heat in resistor... i thought you had a similar coil and could just say the changes that need to be made.... i have 100 ohm resistor right before the bases on my coil and they stay cool, its just the 100 ohm and or rheostat parallell'd to the yellow 10uf capacitor that heat up.... ive made a couple of these back in the day with different coils and smaller capacitors and such, but whenever i push em into the square wave and beyond i find heat starts to come out in that resistor....

[min2oly]

Patrick,
Just looked at your schematic again and I did not put the 100 ohm resistor after the diode before the base will that help? I'll try it. Al

yes/no that may or may not help. I think I've wrote about this before... there are 4 components here to balance

CAP
POT
Diode
RESISTOR

each of these actually control 4 separate things.

CAP - controls the freq
POT - more subtle and difficult to understand - controls your ability to control the freq of the CAP.
DIODE - allows you to have multiple spikes per "cap dump"(this refers to the above cap)
DIODE - also allows the energy to go ONLY in one direction.

RESISTOR - controls the ON time of the frequency - if you think about it, it's pretty common sense, by having a little resistance here it will take longer for the cap to discharge to the base and the transistor will be ON longer

I'll ask the same question, have you been able to run the experiment I show in the vid w/o Pot or Diode?
Thanks,
Patrick

[min2oly]

ive got a 8 primary 18awg and a 20awg trigger...130'.... its air core and im using one of those yellow 250v capacitors of ricks.... i thought you were running one of yours off this same cap?? the frequency is quite low about 850hz when running it at full power (4amps) and about 1500hz at the point of switchover to squarewave.... about 2.2 amps

Fantastic! That's a good cap for that coil. Now, did you try the experiment I show in the video w/o the diode or resistor?
Patrick

[aln]

Patrick,
Just looked at your schematic again and I did not put the 100 ohm resistor after the diode before the base will that help? I'll try it. Al

[aln]

Hi Aln,
I'll reply to your inquiry here. I kind of like reading this info all in one thread rather than hunting down snippets...

Not having the resistor there may very well have been the answer...

So I'm assuming you mean the transistor is heating up. Transistors heat up for one reason... too much current through the transistor.

there are many ways to bring that down. find the post where I talk about what the resistor does vs the pot vs the diode in relation to ON time vs duty cycle vs number of pulses.

Once you can control these 3 things, you will control the current going through the transistor.

Also......... what is the resistance on your 14 Awg wire? How many feet you got there :-)
KR - Patrick A.

I have 2 different coils that I am playing with, both have heat on the resistor I tried to describe (in series with the cap that is across the pot and then this hot resistor then to the diode then to the base of the transistor that also gets hot with that resistor in).

One coil is 4 filar, one #20 and three #14. this coil I have the the #20 and one of the #14's in series for the trigger and the other 2 pwr winds in series. Each was about 45', now 90' as they have been placed in series.

The other coil very unconventional: its about 65' of #14 and 130' of #20 (and an extra strand of 75' of #28 to play around with as a generator). So possibly I have too little of resistance/inductance on the #14 wire with my current set up. Thanks for bringing me to this thread, knew it existed but forgot where it was. Al

[Brodie Gwilliam]

ive got a 8 primary 18awg and a 20awg trigger...130'.... its air core and im using one of those yellow 250v capacitors of ricks.... i thought you were running one of yours off this same cap?? the frequency is quite low about 850hz when running it at full power (4amps) and about 1500hz at the point of switchover to squarewave.... about 2.2 amps

[min2oly]

in my cpd ssg i also get heat in my resistor thats parallel with the capacitor.... its rheostat and a 100 ohm 20w resistor so it never falls below 100 ohms... i never really get much heat on my trannies but that 100 ohm resistor gets pretty damn hot.... it sure charges amazing but always wondered why there was so much heat there

Hi Brodie,
any heat produced is heat wasted, my first analysis would be to look at the size cap you are using vs resistance across that cap. The cap is what should drive your frequency. you can change the freq by sizing the cap. You might be driving it too hard?

Large cap takes longer to fill therefore your freq will be slower. You want to size the cap based on your coil and the battery you are charging.

once you do that then you bring in the resistance across the cap. Watch this method for that:

Here are a few ramblings I hoped might help anyone trying to get free triggering and better charging from their solid state devices. It should be very simple:

Kind Regards,
Patrick

Some people have left out the Pot/resistor across the cap and the diode altogether and have had fantastic results just using the cap. Being able to do this will depend on your transistors and coil...
Hope that helps,
Patrick A.