Here is the circuit diagram of an ultrasonic mosquito repeller. The circuit is based on the theory that insects like mosquito can be repelled by using sound frequencies in the ultrasonic (above 20KHz) range. The circuit is nothing but a PLL IC CMOS 4047 wired as an oscillator working at 22KHz. A complementary symmetry amplifier consisting of four tra
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nsistor is used to amplify the sound. The piezo buzzer converts the output of amplifier to ultrasonic sound that can be heard by the insects. Hello, Im an norwegian engineer-student, and I am having your circuit as a project, both making and attempting to explain it. Making it wont be that much of a problem, but understanding it is a little more tricky. I wondered if you could explain a little bit how/why you have used 4 transistors, for example, and why this circuit will work the way it does. Hi This is called bridged push pull output. This circuit will provide 4 times the normal 2 transistor push pull output connecting through a coupling capacitor. IC 4047 is an oscillator whose frequency is set by R1 & C1. The complimentary output of the IC which is available on pin no 10 & 11 are fed to the bridged output circuit. Since the frequency used for repelling mosquitoes is in the ultrasonic range a piezo transducer, which respond to Ultrasonic sound better is used for producing sound, instead of standard loud speaker. We`re a group of volunteers and opening a brand new plan in our little local community. Your website offered us with beneficial info to work on. You have done a striking position and our complete community shall be thankful to you. Hi Susan connect 4. 7nF in parallel to C1 the oscillator frequency will be in audible range. now check any out put is there if not check all the components and IC pin connections. if...
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This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power....
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