| 摘要 |
A buzzer includes a piezoelectric diaphragm and a housing enclosing the diaphragm and defining a resonating chamber. The chamber includes a sound port and has an optimal resonating frequency fHt at a temperature T defined by fHt=(vt/2pi)(√(A/voL)) were vt is the velocity of sound waves in air at a temperature T, A is the effective area of the sound port, vo is the volume of the resonating chamber, and L is the effective length of the sound port. A temperature compensating member moves in response to changes in temperature to change the value of √(A/voL) at a rate and in a manner that balances the change in 1/vt across that same temperature range, thereby reducing changes in the product (vt/2pi)(√(A/voL)) and consequently reducing any changes that would otherwise occur in fHt across that temperature range, thereby holding the value of fH substantially constant across the temperature range.
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