Self-Resonance Piezo Buzzer with 1-18V

As power is first applied, the piezo is drawing a lot of current through R1 & 2 and shunts it away from the base of the transistor. At some point, as the piezo begins to saturate, the shunting effect diminishes to the point where the transistor starts turning on. This starts discharging the piezo, which is basically a capacitor with a special dielectric. The rate of charge and discharge is also coupled to the deflection of the piezo material, which is also coupled to the air around it and any cavaties which happen to be nearby. This sets up a see-sawing of the mechanical and electrical components at the resonance frequency of this whole “system”.

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This entry was posted on Friday, April 4th, 2008 at 11:18 am and is filed under Audio - Alarm, basic electronics. You can follow any responses to this entry through the RSS 2.0 feed.