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 Best arc I can get with 555
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| Platinum |
 Mon Feb 27 2012, 01:50PM |
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Registered Member #3926
Joined: Fri Jun 03 2011, 03:32PM
Location: UK.
Posts: 489
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Don't know why the driver I have just fails, gets warm on 12v input...
Here the 555 in 13vdc, and 45volts into the FET, limited by the primary of a ignition coil, as it's the only thing that doesn't melt, because of oil in it.
Sorry about the quality couldn't focus webcam...
Very little arcs here about 3.4cm very low current... :(
Why so fail?
Here is a schematic...
Zener and UF4007 removed. Could get more power by removing the limiting ignition coil, but I have only 1 555 timer, so I could also replace MOSFET for a better one like IRFP250n or even IRF640n... tried 250n, but it was a lower voltage arc....
I've seen a 555 on 30v 4a and it was very good power, I want higher voltage, not current, I'm also using the flyback's internal primary, which seems to give more power. |
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| Patrick |
| Mon Feb 27 2012, 01:59PM |
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Registered Member #2431
Joined: Tue Oct 13 2009, 04:47PM
Location: Chico, CA. USA
Posts: 3476
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you are connecting the 13vdc with + and ground wires right?
and you are using both + and ground on your 45volt side right?
from your schematic it looks like maybe your 45volt main power is being poorly grounded or sunk through the IC... maybe?
given your posted schematic the 45volt should kill the 555 as you have drawn it.
excluding all the above posibilities, it may be that your timing freq is to short with on-time, or to low in freq... if everything else is correct. |
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| Platinum |
| Mon Feb 27 2012, 02:02PM |
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Registered Member #3926
Joined: Fri Jun 03 2011, 03:32PM
Location: UK.
Posts: 489
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I know how the circuit works.
13VDC to - and + to 555 input, and 45vdc + to vcc+ on the output end of the driver, and - of 45vdc to - of the 555 input...
I think I'm doing it right, maybe I'm wrong?
Ever since I removed the TVS, the circuit is just bad... on 19vdc I could get very big arcs and with 45vdc input big arcs but not as big as 19vdc input when I got the driver...
So what's wrong, is there anything in the circuit that needs replacing because Sulaiman, did use this circuit on 12vdc 1a... |
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| Patrick |
| Mon Feb 27 2012, 02:04PM |
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Registered Member #2431
Joined: Tue Oct 13 2009, 04:47PM
Location: Chico, CA. USA
Posts: 3476
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Platinum wrote ...
I know how the circuit works.
13VDC to - and + to 555 input, and 45vdc + to vcc+ on the output end of the driver, and - of 45vdc to - of the 555 input...
45 volts should not be applied from pins 4,8 to pin 1, on the 555. is it?
what supply are you getting the 45 volts from? where did you get the 19volts from? |
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| Platinum |
| Mon Feb 27 2012, 02:06PM |
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Registered Member #3926
Joined: Fri Jun 03 2011, 03:32PM
Location: UK.
Posts: 489
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I have applied 45vedc where it says 20vdc on the schematic... |
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| Patrick |
| Mon Feb 27 2012, 02:08PM |
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Registered Member #2431
Joined: Tue Oct 13 2009, 04:47PM
Location: Chico, CA. USA
Posts: 3476
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disconnect your 45v supply, reconnect your 19v supply and tell me how well the 19v circuit works...do you still get the High energy output like before? |
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| m4ge123 |
| Mon Feb 27 2012, 02:10PM |
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Registered Member #4118
Joined: Mon Oct 03 2011, 11:50AM
Location: MD
Posts: 140
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Take out the ignition coil... |
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| Platinum |
| Mon Feb 27 2012, 02:12PM |
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Registered Member #3926
Joined: Fri Jun 03 2011, 03:32PM
Location: UK.
Posts: 489
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19vdc is terrible, it shuts off as it pulls to much current. MOSFET needs a fan...
Sorry about this schematic, but this is how I power the circuit.
Instead of 19vdc I'm using 45vdc for more power, the 19vdc is a laptop SMPS, 19v 4a.
The 45vdc is a CB radio supply, I modified, for just the transformer and bridge and smoothing caps, and it output 45vdc and 20a shortcircuit, then the voltage drops to 25v...
Thanks for helping.
If I take out the ignition coil, then I'll probably blow it up.
Maybe an IRFP250N would be better...
Before I used 5v for the 555, but the gate threshhold is 10v I think, so now I use 13v to turn the gate on all the way. |
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| Patrick |
| Mon Feb 27 2012, 02:15PM |
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Registered Member #2431
Joined: Tue Oct 13 2009, 04:47PM
Location: Chico, CA. USA
Posts: 3476
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Platinum wrote ...
If I take out the ignition coil, then I'll probably blow it up.
yes it will.
I presume you are using the primary of the iggy as the limiter? |
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| Platinum |
| Mon Feb 27 2012, 02:18PM |
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Registered Member #3926
Joined: Fri Jun 03 2011, 03:32PM
Location: UK.
Posts: 489
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Yes, and I'm also using the primary of flyback...
So any problem with the circuit? |
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| Patrick |
| Mon Feb 27 2012, 02:19PM |
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Registered Member #2431
Joined: Tue Oct 13 2009, 04:47PM
Location: Chico, CA. USA
Posts: 3476
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Platinum wrote ...
Yes, and I'm also using the primary of flyback...
So any problem with the circuit?
you should be getting hv out of both then, the iggy and flyback.
your effectivley dividing your 45v and whatever Amps between two transformers, with vastly different frequency behaviours. i trying to think.... what freq are you operating the 555 at? |
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| Platinum |
| Mon Feb 27 2012, 02:20PM |
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Registered Member #3926
Joined: Fri Jun 03 2011, 03:32PM
Location: UK.
Posts: 489
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No, the frequency is very high for the ignition coil.
Is there anything in the circuit that needs taking out, mind you the circuit is a awesome plasma speaker on 45volts. |
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| Patrick |
| Mon Feb 27 2012, 02:23PM |
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Registered Member #2431
Joined: Tue Oct 13 2009, 04:47PM
Location: Chico, CA. USA
Posts: 3476
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Platinum wrote ...
No, the frequency is very high for the ignition coil.
Is there anything in the circuit that needs taking out, mind you the circuit is a awesome plasma speaker on 45volts.
the iggy wont respond well above 6khz, but the flyback wont do well until above 10kHz or more, the iron of the iggy and ferrite of the flyback are not series compatible. thats your problem.
i think you should get a 10 or 20 ohm power resistor, then change the freq and on-time. |
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| Platinum |
| Mon Feb 27 2012, 04:57PM |
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Registered Member #3926
Joined: Fri Jun 03 2011, 03:32PM
Location: UK.
Posts: 489
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But it works bad without the iggy too.
Conundrum... |
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| Marko |
| Tue Feb 28 2012, 04:22AM |
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Registered Member #89
Joined: Thu Feb 09 2006, 08:40AM
Location: Zadar, Croatia
Posts: 3142
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Hm, the output looks great to me for such a crappy circuit, especialy if you've put an ignition coil or whatever in series with flyback primary?
You can limit the voltage overshoot by placing a capacitor in parallel with the mosfet, which will recycle the stored energy back to the supply.
The flyback will still saturate when drawing arcs though and very hot or blown mosfets would be no surprise.
And actually, I've shown you a schematic based on UC3842 some time ago that solved both problems, but you decided to ignore it.
Marko |
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| Platinum |
| Tue Feb 28 2012, 06:57AM |
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Registered Member #3926
Joined: Fri Jun 03 2011, 03:32PM
Location: UK.
Posts: 489
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I don't have the parts to build that, but I'm going to try to build a halfbridge soon... |
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| Patrick |
| Tue Feb 28 2012, 11:38AM |
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Registered Member #2431
Joined: Tue Oct 13 2009, 04:47PM
Location: Chico, CA. USA
Posts: 3476
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Platinum wrote ...
I don't have the parts to build that, but I'm going to try to build a halfbridge soon...
A halfbridge is way more complicated than any of the circuits you have so far built, and i dont think you have learned enough yet to move on to a bridge arrangment of any kind yet. if you cant get the parts for a UC type ic circuit, i seriously doubt youll get even some of the parts needed for a half bridge.
you still have much to learn about the single switches before you will be able to move on.
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| Platinum |
| Tue Feb 28 2012, 06:10PM |
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Registered Member #3926
Joined: Fri Jun 03 2011, 03:32PM
Location: UK.
Posts: 489
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I know how ZVS works, and 555, but not much, anyway I would still like to build a halfbridge, or at least a good driver...
I don't like the 555, and I don't like the ZVS driver. |
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| __=|(:3)-|--{__ |
| Tue Feb 28 2012, 07:38PM |
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Registered Member #3324
Joined: Sun Oct 17 2010, 01:57PM
Location: UK, Dorset, Broadstone 
Posts: 816
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Just.. learn how it works inside out and dont kill yourself with it, a halfbridge can be more dangerous then a ZVS if used in the 'correct' way, i was really worried when you were saying how youve been getting electricuted by the ZVS i sold you... just stay alive
-Tom Williamson |
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| ASHPoD |
| Tue Feb 28 2012, 07:48PM |
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Registered Member #4016
Joined: Wed Jul 20 2011, 08:52PM
Location: Orlando, FL
Posts: 576
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Ask quack, he is telling me how to make one.
this is the schematic he's telling me to use:
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| Platinum |
| Wed Feb 29 2012, 06:30AM |
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Registered Member #3926
Joined: Fri Jun 03 2011, 03:32PM
Location: UK.
Posts: 489
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Tom Williamson wrote ...
Just.. learn how it works inside out and dont kill yourself with it, a halfbridge can be more dangerous then a ZVS if used in the 'correct' way, i was really worried when you were saying how youve been getting electricuted by the ZVS i sold you... just stay alive
-Tom Williamson
I going to go halfbridge, if I die I die, which I wont....The ZVS you sold me was fail, I've made it alot better... |
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| Alex1M6 |
| Wed Feb 29 2012, 08:31AM |
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Registered Member #3943
Joined: Sun Jun 12 2011, 12:24PM
Location: The Shire, UK
Posts: 458
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HighVoltageChick wrote ... Ask quack, he is telling me how to make one. this is the schematic he's telling me to use:
 |
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| Daedronus |
| Wed Feb 29 2012, 12:20PM |
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Registered Member #2329
Joined: Tue Sep 01 2009, 03:25AM
Location:
Posts: 314
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lol, my feelings exactly
on the other hand not long ago I was trying to drive high side mosfets with low side drivers and wandering why it didn't work.
in my case just as in this case the problem is a lack of understanding of basic stuff. |
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| Platinum |
| Wed Feb 29 2012, 01:35PM |
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Registered Member #3926
Joined: Fri Jun 03 2011, 03:32PM
Location: UK.
Posts: 489
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Yes I'm a noob, but I have basic understanding how 555 and halfbridges work...
I would like to build a simple h bridge... |
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| Patrick |
| Wed Feb 29 2012, 09:16PM |
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Registered Member #2431
Joined: Tue Oct 13 2009, 04:47PM
Location: Chico, CA. USA
Posts: 3476
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Platinum wrote ...
... but I have basic understanding how 555 and halfbridges work...
I think not, or your previous circuits would be working well by now.
I dont want to discourage you, or be too harsh, but thats how i see it. Also you really need a O-scope for a full h bridge, the timing of the gate waveforms are pretty important. |
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| teravolt |
| Wed Feb 29 2012, 10:43PM |
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Registered Member #195
Joined: Fri Feb 17 2006, 02:27PM
Location: Berkeley, ca.
Posts: 980
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hi Platinum, a 555 has a voltage range of 3-18 rail voltage . take R4 and put it in series with the drain and ground your source same as pin 1 on the 555. you could try putting your uf4007 in series with R4 as I sujested or in parallel with the drain and source. I suspect that you are getting kickback from your coils. each one has a sertian amount of resonance so you want to turn your fet on for only 180 of that frequency. to do this you may want to convert your 555 to a straight oscilator and add a one shot and driver to the output for gate drive. |
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| teravolt |
| Wed Feb 29 2012, 11:30PM |
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Registered Member #195
Joined: Fri Feb 17 2006, 02:27PM
Location: Berkeley, ca.
Posts: 980
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like this
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| Platinum |
| Thu Mar 01 2012, 04:20PM |
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Registered Member #3926
Joined: Fri Jun 03 2011, 03:32PM
Location: UK.
Posts: 489
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Patrick wrote ... Platinum wrote ...
... but I have basic understanding how 555 and halfbridges work...
I think not, or your previous circuits would be working well by now. I dont want to discourage you, or be too harsh, but thats how i see it. Also you really need a O-scope for a full h bridge, the timing of the gate waveforms are pretty important.
When I said basic understanding, I meant it...
Yes I need a O-scope, but I don't have the money... |
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| teravolt |
| Thu Mar 01 2012, 04:40PM |
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Registered Member #195
Joined: Fri Feb 17 2006, 02:27PM
Location: Berkeley, ca.
Posts: 980
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for something basic you could get one of those 1MHz color one chanel 100$ hand dso scope would get you over the hump. I also bought a old tecktronics scope for 100 on ebay |
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| Xray |
| Thu Mar 01 2012, 10:35PM |
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Registered Member #3429
Joined: Sat Nov 20 2010, 08:04PM
Location: Minnesota, USA
Posts: 288
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teravolt wrote ...
for something basic you could get one of those 1MHz color one chanel 100$ hand dso scope would get you over the hump. I also bought a old tecktronics scope for 100 on ebay
Yes, you can get a very nice tektronix scope for a fraction of the original cost. I bought a model 453 dual channel, dual trace portable scope for $160.00 a few years ago, and it's been one of my most valuable and most used pieces of test equipment.
I've heard mixed reviews of those little color pocket scopes. I never played with one, so I don't know how good or how bad they are, but in my opinion if you're going to spend that much money for scope, you would be better off buying a used American made tek or hp scope. Just make sure that the buyer gives you some sort of guarantee or right of return in case it doesn't work, or is in poor condition. |
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