2007-07-14 14:48:24 · 4 answers · asked by hello 1 in Science & Mathematics ➔ Engineering
There are lots of different types. The early PC computers used a small loudspeaker driver purely for beeping. This would be a "moving coil" magnetic transducer.
I'd guess that the most common buzzer is the piezo-electric unimorph disk. It is a bilaminar sandwich of a thin piezo or ferroelectric material (e.g. lead zirconate titanate PZT) and a thin metal disk (e.g. brass).
When an AC voltage is applied across the piezo material it expanded and contracts. This causes the whole disk to flex in a manner similar to a bi-metallic thermometer. The flexing disk radiates sound.
2007-07-15 08:21:11 · answer #1 · answered by Tom H 4 · 0⤊ 0⤋
Both answers cover it but the DC buzzer explanation is wrong. In the DC version there is a contact that is opened when the steel blade is attracted to an electromagnet. When that opens the circuit the electromagnet loses its attraction for the moving blade and the blade snaps back to the closed position. They cycle repeats with that annoying buzz sound.
2007-07-14 23:06:33 · answer #2 · answered by Rich Z 7 · 1⤊ 0⤋
That's only a partial answer Heinz. The magnetic poles are created by electromagnets, and they alternate polarity because they are driven by alternating current. The alternation of polarity causes the metal blade to move back and forth at a high enough frequency to make a buzzing sound. The magnets can also be driven by a direct current battery, but there has to be a circuit with a capacitor to create an alternation of the current.
2007-07-14 22:26:20 · answer #3 · answered by mr.perfesser 5 · 0⤊ 0⤋
A metal blade vibrating between two magnetic poles. ~
2007-07-14 21:57:37 · answer #4 · answered by Anonymous · 1⤊ 0⤋