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大多数有内部激励器的压电蜂鸣器的声压在9V电池供电时只能达到80dB左右。本电路用9V电池可产生震耳欲聋的110dB声响。 本电路用一块六反相施密特触发器IC和一个带有反馈端子的压电器件组成,反馈端在压电晶片的中央区域。当激励蜂鸣器谐振时,反馈信号达到最大值。 74C14中的一只反相器接成一个无稳态振荡器。频率选择在压电晶片谐振频率3.2kHz的1/5。由于蜂鸣器
Most piezo buzzers with internal actuators have a sound pressure of only about 80dB when powered by a 9V battery. The circuit with 9V battery can produce deafening 110dB sound. The circuit consists of a six-inverting Schmitt trigger IC and a piezo-electric device with a feedback terminal in the center of the piezo-electric wafer. When the stimulus buzzer resonance, the feedback signal reaches the maximum value. An inverter in the 74C14 is connected as a non-steady state oscillator. The frequency is chosen to be 1/5 of the 3.2 kHz resonance frequency of the piezoelectric wafer. Thanks to the buzzer