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Hi, I'm Marshall Brain With today's question, how does the lighter in a barbeque grill work? In a barbeque grill, you normally have a push button lighter. You push the button, it makes a clunking sound, and a spark appears inside the gas grill. How does that work? A barbeque lighter uses something called piezoelectricity to generate a nice spark that lights the grill. Piezo, in Greek, means pressure. You find piezoelectric materials in a number of different places. For example, all of these products depend on the piezoelectric effect.
The push button lighter in a barbeque grill, the push button lighter on a cigarette lighter - piezoelectric beepers, which are common in digital watches and just about anything electronic that goes beep. Piezoelectric tweeters in stereo speakers - the sound generating rays for sonar, fish finders, and ultrasound devices, crystal microphones, phonograph needles, and the quartz crystals used in most digital clocks, watches, and timers as the time base.
Certain crystalline materials, like quartz or shell salts and certain ceramics have piezoelectric properties. When you apply pressure to them, you get a charge separation within the crystal and a voltage across the crystal that is sometimes extremely high. For example, in a barbeque lighter, the popping noise you hear is a little spring-loaded hammer hitting a crystal and generating thousands of volts across the two faces of the crystal. A voltage this high is identical to the voltage that drives a spark plug in a gasoline engine.
The crystal's voltage can generate a nice spark that lights the gas of the grill. In a crystal microphone, air pressure deforms the crystal enough to cause very small voltage changes in the crystal. These voltage changes are amplified and used to record or transmit sounds. Piezoelectric materials also work the other way. If you apply a voltage across the crystal, the crystal will change shape. The change in shape is very slight in most cases, but it's enough to drive small speakers.
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