Piezo ignitor pulse shape
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Posted by Arnold on September 21, 2008, 6:01 am
Please log in for more thread options 1) I am wondering whether the piezo ignitor of a BBQ lighter generates a single spark or multiple sparks. 2) In other words, I would like to know the pulse shape of the piezo ignitor, but I haven't got an oscilloscope. Is it AC or DC, is it a single monopolar pulse, or a bipolar pulse, or a dampened oscillation? Probably the pulse shape depends on its design, so I dissected a piezo ignitor. Please see the image at http://s365.photobucket.com/albums/oo98/jkien_photos/?action=view¤t=IMG_6175.jpg The piezo electric body is apparently composed of some indistinct grey matter in a relatively large brass cup. 3) is the grey matter the piezo ceramic (PZT)? 4) what is the purpose of the relativey large brass mass. Is it just a heavy anvil? | ||||||||||||||||||||||||||||
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Posted by amdx on September 21, 2008, 1:52 pm
Please log in for more thread options > The piezo electric body is apparently composed of some indistinct grey
> matter in a relatively large brass cup. > 3) is the grey matter the piezo ceramic (PZT)? > 4) what is the purpose of the relativey large brass mass. Is it just a > heavy anvil? > > Take a look at this page, do a find for PZT on the page. It shows waveforms and Q. Although I don't make any sense of either of those. I think the voltage and the Q is much higher than what it says. physics.mercer.edu/hpage/technique.htm Mike | ||||||||||||||||||||||||||||
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Posted by Arnold on September 21, 2008, 4:09 pm
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>
> > > > > > > 1) I am wondering whether the piezo ignitor of a BBQ lighter generates
> > a single spark or multiple sparks. >
> > 2) In other words, I would like to know the pulse shape of the piezo
> > ignitor, but I haven't got an oscilloscope. Is it AC or DC, is it a > > single monopolar pulse, or a bipolar pulse, or a dampened > > oscillation? >
> > Probably the pulse shape depends on its design, so I dissected a piezo
..
> > ignitor. Please see the image at > >http://s365.photobucket.com/albums/oo98/jkien_photos/?action=3Dview&cur.= > > The piezo electric body is apparently composed of some indistinct grey
> > matter in a relatively large brass cup. > > 3) is the grey matter the piezo ceramic (PZT)? > > 4) what is the purpose of the relativey large brass mass. Is it just a > > heavy anvil? >
Thanks for the link, although it seems to discuss damping in PZT in a
> =A0 Take a look at this page, do a find for PZT on the page. It shows > waveforms and Q. Although I > don't make any sense of either of those. I think the voltage and the Q is > much higher > than what it says. > =A0physics.mercer.edu/hpage/technique.htm > very different situation than an ignitor. For example, the PZT in figure 17 has a resonance frequency of about 1 Hz. That is not very typical for an ignitor. | ||||||||||||||||||||||||||||
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Posted by Jasen Betts on September 21, 2008, 4:09 pm
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> 1) I am wondering whether the piezo ignitor of a BBQ lighter generates
> a single spark or multiple sparks. that depends on the spark gap, and the how the mecahnical stuff perfroms.... > 2) In other words, I would like to know the pulse shape of the piezo
> ignitor, but I haven't got an oscilloscope. Is it AC or DC, is it a > single monopolar pulse, or a bipolar pulse, or a dampened > oscillation? yes. piezos work by pushing electrons round when you deform them as they return to their base shape the electrons are pushed back the other way so it'll be bipolar. little else can be predicted. > Probably the pulse shape depends on its design,
yup but not in a precisely predictable way. the electrical load piezo will have a large effect too, and given that the load includes a spark gap the effect won't be easily predictable. > 3) is the grey matter the piezo ceramic (PZT)?
that or a coating to protect it. > 4) what is the purpose of the relativey large brass mass. Is it just a
> heavy anvil? I expect so. For an indication of the waveform produced by the piezo without the spark gap consider the sound it makes. Bye. Jasen | ||||||||||||||||||||||||||||
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Posted by Arnold on September 22, 2008, 6:44 am
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>
> > 1) I am wondering whether the piezo ignitor of a BBQ lighter generates
> > a single spark or multiple sparks. >
> that depends on the spark gap, and the how the mecahnical stuff > perfroms.... > > > 2) In other words, I would like to know the pulse shape of the piezo
> > ignitor, but I haven't got an oscilloscope. Is it AC or DC, is it a > > single monopolar pulse, or a bipolar pulse, or a dampened > > oscillation? >
> yes. > > piezos work by pushing electrons round when you deform them as they > return to their base shape the electrons are pushed back the other way > so it'll be bipolar. > > little else can be predicted. > > > Probably the pulse shape depends on its design,
>
> yup but not in a precisely predictable way. > > the electrical load piezo will have a large effect too, > and given that the load includes a spark gap the effect > won't be easily predictable. > > > 3) is the grey matter the piezo ceramic (PZT)?
>
> that or a coating to protect it. > > > 4) what is the purpose of the relativey large brass mass. Is it just a
> > heavy anvil? >
gap
> I expect so. > > For an indication of the waveform produced by the piezo without the spark= > consider the sound it makes.
> > Bye. > =A0 =A0Jasen Thanks for your reply. BTW, with a bipolar pulse I meant just a single sign alternation, whereas apparently your definition is a sequence with an arbitrary number of sign alternations. Probably your definition is better. I considered the impact sound of the hammer, which sounds as if the body doesn't ring for longer than about 0.1 ms. However, that doesn't say much about the waveform. | ||||||||||||||||||||||||||||
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> a single spark or multiple sparks.
>
> 2) In other words, I would like to know the pulse shape of the piezo
> ignitor, but I haven't got an oscilloscope. Is it AC or DC, is it a
> single monopolar pulse, or a bipolar pulse, or a dampened
> oscillation?
>
> Probably the pulse shape depends on its design, so I dissected a piezo
> ignitor. Please see the image at
>