# Lightning and piezo

**URL:** <https://boards.straightdope.com/t/lightning-and-piezo/636860>\
**Category:** Factual Questions\
**Created:** [October 5, 2012, 11:22pm UTC](https://boards.straightdope.com/t/lightning-and-piezo/636860 "2012-10-05T23:22:09Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![carnivorousplant](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnivorousplant/32/3563_2.png) [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)\
**Post date:** [October 5, 2012, 11:22pm UTC](https://boards.straightdope.com/t/lightning-and-piezo/636860/1 "2012-10-05T23:22:09Z")

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Why does the piezo igniter on the stove top go off when lightning occurs?

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**Author:** ![Michael63129](https://avatars.discourse-cdn.com/v4/letter/m/3da27b/32.png) [@Michael63129](https://boards.straightdope.com/u/Michael63129)\
**Post date:** [October 6, 2012, 4:40am UTC](https://boards.straightdope.com/t/lightning-and-piezo/636860/2 "2012-10-06T04:40:15Z")

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I don’t know the exact circuit used, but if you are talking about the kind of gas stove where a spark occurs when you turn it on, they probably use [this sort of circuit](http://www.oocities.org/capecanaveral/lab/5322/simpleign.htm), which is extremely simple and capable of generating very high voltages (FWIW, a [piezo ignitor](http://en.wikipedia.org/wiki/Piezo_ignition) is the kind you manually click together to generate a spark). One thing to note is that a TRIAC is used as the switch, and they are susceptible to false triggering by voltage spikes on the power line, as mentioned [here](http://en.wikipedia.org/wiki/Thyristor#Failure_modes) (switch on dv/dt, meaning an excessive rate of voltage rise). Also, I have a touch-activated lamp that occasionally flickers on for a split second during a storm for the same reason (and sometimes even during a clear day).

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**Author:** ![eschereal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eschereal/32/18939_2.png) [@eschereal](https://boards.straightdope.com/u/eschereal)\
**Post date:** [October 6, 2012, 4:53am UTC](https://boards.straightdope.com/t/lightning-and-piezo/636860/3 "2012-10-06T04:53:21Z")

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> [@Michael63129](#):
>
> I have a touch-activated lamp that occasionally flickers on for a split second during a storm for the same reason (and sometimes even during a clear day).

A lightning bolt can [travel 25 miles](http://news.discovery.com/earth/lightning-on-clear-day-110729.html). The day may be clear where you are, but there could be a storm over yonder.

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**Author:** ![carnivorousplant](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnivorousplant/32/3563_2.png) [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)\
**Post date:** [October 6, 2012, 1:31pm UTC](https://boards.straightdope.com/t/lightning-and-piezo/636860/4 "2012-10-06T13:31:39Z")

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Thanks, Michael.

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**Author:** ![johnpost](https://avatars.discourse-cdn.com/v4/letter/j/f17d59/32.png) [@johnpost](https://boards.straightdope.com/u/johnpost)\
**Post date:** [October 6, 2012, 2:33pm UTC](https://boards.straightdope.com/t/lightning-and-piezo/636860/5 "2012-10-06T14:33:21Z")

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i agree that lightning travels far and can do strange things, it puts voltage in many places.

it can ring your phone too.