Many barbeque lighters use a piezoelectric crystal to create a spark to
ignite a gas such as butane. When the crystal is used in this way it is
often refered to as a piezoelectric igniter. The source of the gas is
contained within the lighter body. If you remove this piezoelectric
crystal while keeping the trigger mechanism and wires attached, you can
see that it creates a spark around 7mm in length. This is in the kilovolt
I needed such a crystal so I purchased one of these lighters and removed
it as the following pictures show. Care must be taken
in taking it apart since there is a flamable liquid under pressure here.
I first kept lighting the lighter until it wouldn't light anymore in order
to decrease this pressure. Note that this decreased the amount of fluid
by only half so care must still be taken after this point.
The lighter. Note that this has been reassembled
for purposes of taking this picture but without the trigger. But this
illustrates what you should look for in the stores.
Here it is after disassembly (trigger and crystal
not shown, see pictures below for these). You basically pull
off the long black part. Then you pull off the shorter black part.
The part with the flamable liquid is on the right. You have to CAREFULLY
cut this away while splitting the remaining body part as the picture
Here is it with the body split apart. At this stage
you can remove the trigger and crystal.
The trigger and crystal. At this point you can hold
the ends of the wires about 7mm apart and work the trigger. When you do,
you'll see a part between the wire ends. If you don't get a spark then
you're probably shorting the wires with your fingers where you're holding
on to the crystal. Move your fingers away from the wires.
The crystal is the light olive colored part
that the wires connect to. In the Testing section below you can see
I didn't make any measurements or take pictures with the kilovolt spark.
However, having extracted the crystal, I did some simple measurements
hitting it in other ways.
Actually, the crystal is a cylinder embedded in the
rectangular plastic and epoxy body so you never see it. On one end is
a small metal ball. This is the end you hit. The pressure is applied
on the same axis as the polarity. Here I'm flicking it with my fingernail.
This is the resulting 4.16 volts as a result of the
flick with my fingernail.
Here I'm hitting it against the table top.
This is the resulting 240 volts as a result of hitting
it against the table top. Note that I've seen voltages as high as 500 volts,
the highest my oscilloscope will show.
Here's a step-by-step video I made of another BBQ lighter I took apart.
This crystal is cylindrical and wired a bit differently.
Piezoelectric static electricity generator
You can turn your igniter into a piezoelectric static electricity generator.
As stated above, with the
wires separated about 7mm apart you get a spark between the two sharp ends
of the wires. Very roughly, that's 21,000V, assuming 3000V per mm. But what
if those ends weren't sharp and were separated by more distance? Make one end
be a smooth metal ball. The other end, the earth electrode, is the long black part in
the 2nd photo above. Now, instead of a spark, the positive and the
nagative charges (the high voltage) remains on the two electrodes.
Using one hand, touch the earth
electrode with one finger and move another finger close to the ball.
A spark should jump to your finger. You may have to sand off the part of
the earth electrode that your finger will touch in order to get good
Other piezoelectricity explorations