Creating sparks with a mosfet and ignition coil

Started by May 22, 2014
I would like to generate a series of ~1000 volt sparks continuously, for several
hours, using a spare automotive ignition coil I have lying around.  

I found this 555 circuit online:
http://www.sci-experiments.com/HighVoltagePulser/

My questions:
(1) Is a 500-volt MOSFET really necessary?  Would a 100-volt IRF530 work alright
without frying?

(2) Does the 0.1 uF, 250V capacitor take the place of a Schottky snubber diode? 
Which is preferable?

(3) Would this circuit work properly for several hours, or would something (the
coil, the mosfet) give up?

Thanks!

Michael
On Thu, 22 May 2014 09:02:00 -0700 (PDT), mrdarrett@gmail.com wrote:

>I would like to generate a series of ~1000 volt sparks continuously, for several
hours, using a spare automotive ignition coil I have lying around.
> >I found this 555 circuit online: >http://www.sci-experiments.com/HighVoltagePulser/ > >My questions: >(1) Is a 500-volt MOSFET really necessary? Would a 100-volt IRF530 work alright
without frying?
> >(2) Does the 0.1 uF, 250V capacitor take the place of a Schottky snubber diode?
Which is preferable? Change C4 to 1uF 100V, then use IRF530... should be OK.... no warranties, express or implied ;-)
> >(3) Would this circuit work properly for several hours, or would something (the
coil, the mosfet) give up?
> >Thanks! > >Michael
Hard to know, the circuit is a mess of uncontrol. ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.
On Thursday, May 22, 2014 9:23:10 AM UTC-7, Jim Thompson wrote:
> On Thu, 22 May 2014 09:02:00 -0700 (PDT), mrdarrett@gmail.com wrote: > > > > >I would like to generate a series of ~1000 volt sparks continuously, for several
hours, using a spare automotive ignition coil I have lying around.
> > > > > >I found this 555 circuit online: > > >http://www.sci-experiments.com/HighVoltagePulser/ > > > > > >My questions: > > >(1) Is a 500-volt MOSFET really necessary? Would a 100-volt IRF530 work alright
without frying?
> > > > > >(2) Does the 0.1 uF, 250V capacitor take the place of a Schottky snubber diode?
Which is preferable?
> > > > Change C4 to 1uF 100V, then use IRF530... should be OK.... no > > warranties, express or implied ;-)
One microfarad! Huh. Ok!
> >(3) Would this circuit work properly for several hours, or would something (the
coil, the mosfet) give up?
> > > > > >Thanks! > > > > > >Michael > > > > Hard to know, the circuit is a mess of uncontrol. > > ...Jim Thompson
Thanks! Michael
On Thu, 22 May 2014 09:30:23 -0700 (PDT), mrdarrett@gmail.com wrote:

>On Thursday, May 22, 2014 9:23:10 AM UTC-7, Jim Thompson wrote: >> On Thu, 22 May 2014 09:02:00 -0700 (PDT), mrdarrett@gmail.com wrote: >> >> >> >> >I would like to generate a series of ~1000 volt sparks continuously, for several
hours, using a spare automotive ignition coil I have lying around.
>> >> > >> >> >I found this 555 circuit online: >> >> >http://www.sci-experiments.com/HighVoltagePulser/ >> >> > >> >> >My questions: >> >> >(1) Is a 500-volt MOSFET really necessary? Would a 100-volt IRF530 work alright
without frying?
>> >> > >> >> >(2) Does the 0.1 uF, 250V capacitor take the place of a Schottky snubber diode?
Which is preferable?
>> >> >> >> Change C4 to 1uF 100V, then use IRF530... should be OK.... no >> >> warranties, express or implied ;-) > > >One microfarad! Huh. Ok!
A guess based on inductive energy, the original C4 value at 250V ;-)
> > >> >(3) Would this circuit work properly for several hours, or would something (the
coil, the mosfet) give up?
>> >> > >> >> >Thanks! >> >> > >> >> >Michael >> >> >> >> Hard to know, the circuit is a mess of uncontrol. >> >> ...Jim Thompson > > >Thanks! > >Michael
...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.
On Thursday, May 22, 2014 9:57:21 AM UTC-7, Jim Thompson wrote:
> On Thu, 22 May 2014 09:30:23 -0700 (PDT), mrdarrett@gmail.com wrote: > > > > >On Thursday, May 22, 2014 9:23:10 AM UTC-7, Jim Thompson wrote: > > >> On Thu, 22 May 2014 09:02:00 -0700 (PDT), mrdarrett@gmail.com wrote: > > >> > > >> > > >> > > >> >I would like to generate a series of ~1000 volt sparks continuously, for
several hours, using a spare automotive ignition coil I have lying around.
> > >> > > >> > > > >> > > >> >I found this 555 circuit online: > > >> > > >> >http://www.sci-experiments.com/HighVoltagePulser/ > > >> > > >> > > > >> > > >> >My questions: > > >> > > >> >(1) Is a 500-volt MOSFET really necessary? Would a 100-volt IRF530 work
alright without frying?
> > >> > > >> > > > >> > > >> >(2) Does the 0.1 uF, 250V capacitor take the place of a Schottky snubber
diode? Which is preferable?
> > >> > > >> > > >> > > >> Change C4 to 1uF 100V, then use IRF530... should be OK.... no > > >> > > >> warranties, express or implied ;-) > > > > > > > > >One microfarad! Huh. Ok! > > > > A guess based on inductive energy, the original C4 value at 250V ;-)
Should I add a Schottky snubber diode in parallel with the primary coil, for extra MOSFET protection? Or would that interfere with the cap? Thanks, Michael
On Thu, 22 May 2014 10:15:17 -0700 (PDT), mrdarrett@gmail.com wrote:

>On Thursday, May 22, 2014 9:57:21 AM UTC-7, Jim Thompson wrote: >> On Thu, 22 May 2014 09:30:23 -0700 (PDT), mrdarrett@gmail.com wrote: >> >> >> >> >On Thursday, May 22, 2014 9:23:10 AM UTC-7, Jim Thompson wrote: >> >> >> On Thu, 22 May 2014 09:02:00 -0700 (PDT), mrdarrett@gmail.com wrote: >> >> >> >> >> >> >> >> >> >> >> >> >I would like to generate a series of ~1000 volt sparks continuously, for
several hours, using a spare automotive ignition coil I have lying around.
>> >> >> >> >> >> > >> >> >> >> >> >> >I found this 555 circuit online: >> >> >> >> >> >> >http://www.sci-experiments.com/HighVoltagePulser/ >> >> >> >> >> >> > >> >> >> >> >> >> >My questions: >> >> >> >> >> >> >(1) Is a 500-volt MOSFET really necessary? Would a 100-volt IRF530 work
alright without frying?
>> >> >> >> >> >> > >> >> >> >> >> >> >(2) Does the 0.1 uF, 250V capacitor take the place of a Schottky snubber
diode? Which is preferable?
>> >> >> >> >> >> >> >> >> >> >> >> Change C4 to 1uF 100V, then use IRF530... should be OK.... no >> >> >> >> >> >> warranties, express or implied ;-) >> >> > >> >> > >> >> >One microfarad! Huh. Ok! >> >> >> >> A guess based on inductive energy, the original C4 value at 250V ;-) > > >Should I add a Schottky snubber diode in parallel with the primary coil, for extra
MOSFET protection? Or would that interfere with the cap?
> >Thanks, > >Michael
That will interfere with the energy transfer. ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.
On 05/22/2014 06:02 PM, mrdarrett@gmail.com wrote:
> I would like to generate a series of ~1000 volt sparks continuously, for several
hours, using a spare automotive ignition coil I have lying around.
> > I found this 555 circuit online: > http://www.sci-experiments.com/HighVoltagePulser/ > > My questions: > (1) Is a 500-volt MOSFET really necessary? Would a 100-volt IRF530 work alright
without frying?
> > (2) Does the 0.1 uF, 250V capacitor take the place of a Schottky snubber diode?
Which is preferable?
> > (3) Would this circuit work properly for several hours, or would something (the
coil, the mosfet) give up?
> > Thanks! > > Michael
The link incorrectly states that "Energy flows back and forth resonantly between the magnetic field in the coil and the electric field in the capacitor, with a period given approximately by 2 pi x Sq. Rt. (LxC), the energy decaying rapidly as energy is transferred to the secondary side spark and to the wiring resistance." This would certainly be the case if there was no spark at the secondary. As soon as there is a spark you have to switch in a new circuit model with a low resistance which rapidly absorbs the stored energy. So only the first part (less than T/4) of a sinusoid is seen after switching. Pere
In article <937da223-9089-4d09-9082-ff101fc48ba2@googlegroups.com>, 
mrdarrett@gmail.com says...
> > I would like to generate a series of ~1000 volt sparks continuously, for several
hours, using a spare automotive ignition coil I have lying around.
> > I found this 555 circuit online: > http://www.sci-experiments.com/HighVoltagePulser/ > > My questions: > (1) Is a 500-volt MOSFET really necessary? Would a 100-volt IRF530 work alright
without frying? yes, it should be used for maximum effect!
> > (2) Does the 0.1 uF, 250V capacitor take the place of a Schottky snubber diode?
Which is preferable? It's a controlled release. In other words, it does not completely clamp the voltage, which is why you need a High Voltage fet.
> (3) Would this circuit work properly for several hours, or would something (the
coil, the mosfet) give up?
>
Should work just fine.
> Thanks! > > Michael
Jamie
On Thursday, May 22, 2014 3:39:13 PM UTC-7, Maynard A. Philbrook Jr. wrote:
> In article <937da223-9089-4d09-9082-ff101fc48ba2@googlegroups.com>, > > mrdarrett@gmail.com says... > > > > > > I would like to generate a series of ~1000 volt sparks continuously, for several
hours, using a spare automotive ignition coil I have lying around.
> > > > > > I found this 555 circuit online: > > > http://www.sci-experiments.com/HighVoltagePulser/ > > > > > > My questions: > > > (1) Is a 500-volt MOSFET really necessary? Would a 100-volt IRF530 work alright
without frying?
> > yes, it should be used for maximum effect! > > > > > > (2) Does the 0.1 uF, 250V capacitor take the place of a Schottky snubber diode?
Which is preferable?
> > It's a controlled release. In other words, it does not completely clamp > > the voltage, which is why you need a High Voltage fet. > > > > > (3) Would this circuit work properly for several hours, or would something (the
coil, the mosfet) give up?
> > > > > Should work just fine. > > > > > Thanks! > > > > > > Michael > > > > > > Jamie
Okie doke! Thanks! Michael
On Thu, 22 May 2014 09:02:00 -0700 (PDT),
mrdarrett@gmail.com wrote:

>I would like to generate a series of ~1000 volt sparks continuously, for several
hours, using a spare automotive ignition coil I have lying around.
> >I found this 555 circuit online: >http://www.sci-experiments.com/HighVoltagePulser/ > >My questions: >(1) Is a 500-volt MOSFET really necessary? Would a 100-volt IRF530 work alright
without frying? Back in the day (late '60s, early '70s) when I worked for the auto industry, the voltage across the breaker points in the primary of a mechanical-type system could easily go over 300V. I don't recall checking the equivalent in the electronically-switched types, but they did put out a lot more secondary volts. So you probably ought to stick with the 500V part. Best regards, Bob Masta DAQARTA v7.50 Data AcQuisition And Real-Time Analysis www.daqarta.com Scope, Spectrum, Spectrogram, Sound Level Meter Frequency Counter, Pitch Track, Pitch-to-MIDI FREE Signal Generator, DaqMusiq generator Science with your sound card!