110Db Beeper Circuit


Posted on Nov 11, 2012

This circuit will generate an ear-splitting 110 dB from 9 V. The setup uses a single 74C14 (CD40106B) CMOS hex inverting Schmitt-trigger IC, wliich must be used with a piezoelectric device with a feedback terminal. The feedback terminal is attached to a central region on the piezoelectric wafer. When the beeper is driven at resonance, the feedback signal peaks. One inverter of the 74C14 is wired as an astable oscillator, The frequency is chosen to be 5 times lower than the 3.2 kHz resonant frequency of the piezoelectric device. Feedback from the third pin of the beeper reinforces the correct drive frequency to ensure maximum sound output.


110Db Beeper Circuit
Click here to download the full size of the above Circuit.

Four other inverter sections of the IC are wired to form two separate drivers. The output of one section is cross-wired to the input of the second section. The differential drive signal that results produces about 18-V p-p when measured across the beeper. The last inverter section is wired as a second astable oscillator with a frequency of about 2 Hz. It gates the main oscillator on and off through a diode. For a continuous tone, the modulation circuit can be deleted.




Leave Comment

characters left:

New Circuits

.

 


Popular Circuits

FM Receiver circuit
Parallel-mode aperiodic crystal oscillator
Constant-bandwidth-amplifier
20Db-audio-booster
Reflex Radio Receiver
stepper motor control
heater with ckm005 microcontroller
Alarm Digital Clock-DS1307
Creating DeviceHive application for .NET Micro Framework
Based LB1948M drive motor control circuit diagram
Combustible gas alarm circuit diagram 2 7806 KD28



Top