# ignitor voltage

Discussion in 'General Electronics Chat' started by Sircut5, Jan 23, 2014.

1. ### Sircut5 Thread Starter New Member

Jan 23, 2014
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No particular purpose except mayby safety, I would like to know how I could do a measurement of the spark voltage from an ignitor that is used in barbecues, then convert to and find watts (power)? I can do most math calculations for it so I do not want to know the tech details , Ohms law, just how to measure with some meter? Then I can find the wattage from such a device. My gas stove has one that runs off 110 Ac volts so I assume it is quite powerful, but I want to measure a piezo-electric mechanically generated spark from a barbecue which I have a few of around. A related question , is that spark considered static electricity, AC or DC voltage? Thanks for some feedback about it!
Sircut5.

2. ### Metalmann Active Member

Dec 8, 2012
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Guys will hack and experiment on anything.

3. ### Sircut5 Thread Starter New Member

Jan 23, 2014
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Thanks Metalmann.

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Nov 7, 2013
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5. ### alfacliff Well-Known Member

Dec 13, 2013
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a spark that long ws MUCH greater than 320 volts. be carefull measuring it with your expencive test equipment.

6. ### MrChips Moderator

Oct 2, 2009
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I am not sure how to measure such voltage. What you are observing is a sharp voltage spike for a very short duration from a very high impedance source. Any attempt to measure the voltage will result in killing the voltage.

In reality what is happening is a build up of electric field created by sharp points which ionizes the surrounding air up until you reach and exceed the insulation properties of the surrounding air. Then you get insulation breakdown and the resulting discharge spark.

The breakdown field of air is commonly quoted as 30kV/cm.

7. ### GopherT AAC Fanatic!

Nov 23, 2012
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4,039
You can keep extending the spark gap until you no longer see the spark. Then measure the gap with a spark plug feeler gage.

You then use the instructions in this link to compensate for atmospheric pressure and use the table on that page to calculate voltage. Some references claim your accuracy will be within 5%

here

Energy per spark could be determined with a capacitor if you have a big enough resistor you can punch the sparker several times and watch the voltage increase (no spark should be generated because the cap will prevent the breakdown voltage from bring reached. There are some formulas for coulombs and farads to get to voltage - not at the tip of my pointed brain right now. In any case, you might blow a few caps trying to find the right uF and resistor size. Be careful and find a safe way to discharge a cap before you start. 30000 volts will sting if a small cap, it could kill if a big cap (or the cap could explode violently - don't use electrolytic).

Last edited: Jan 23, 2014
8. ### alfacliff Well-Known Member

Dec 13, 2013
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there are high voltage probes for scopes. usually resistive voltage deviders. of course this will introduce a bit of load, and reduce the indicated voltage spike.

9. ### crutschow Expert

Mar 14, 2008
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The easiest way likely would be to estimate the voltage from the maximum spark gap length that still gives a spark and also measure the capacitance of the ignitor to ground. You can then calculate the energy from P = 1/2 CV$^{2}$. That should be close enough for most purposes.

10. ### ian field Distinguished Member

Oct 27, 2012
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Probably wouldn't do much to an old analogue multimeter (not much area under the curve) - unless that analogue meter has a FET input.

I could very easily resist any temptation to stick a DMM in there!

11. ### BillB3857 Senior Member

Feb 28, 2009
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I think the spark would be long gone before the needle would move.

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12. ### THE_RB AAC Fanatic!

Feb 11, 2008
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They make a spark up to about 4mm through air.

13. ### inwo Well-Known Member

Nov 7, 2013
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That's true. OP mentioned volts measurement.
However OP was ultimately looking for power measurement.

The 320volts measured across a 1meg input should give a rough estimate.
Op may only need to no by factor of 10. Didn't say.

Any other estimates?