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CLAP SWITCH THEORY
Here is a circuit for electronics hobbyists that can switch on & off a light, Fan, Radio etc. by the sound of clap.The sound of clap is received by a small microphone that is shown biased by resistor R1 in the circuit. The microphone changes sound wave in to electrical wave which is further amplified by Q1. Transistor Q1 is used as common emitter circuit to amplify weak signals received by the microphone. Amplified output from the collector of transistor Q1 is then feed to the Bistable Multivibrator circuit also known as flip-flop.
Flip flop circuit is made by using 2 Transistor, in our circuit Q2&Q3. In a flip-flop circuit, at a time only one transistor conduct and other cut off and when it gets a trigger pulse from outside source then first transistor is cutoff and 2nd transistor conducts. Thus output of transistor is either logic-0 or logic-1 and it remains in one state 0 or 1 until it gets trigger pulse from outer source.
The pulse of clap which is trigger for flip-flop makes changes to the output which is complementary (reverse). Decision of flip-flop which is in the low current form is unable to drive relay directly so we have used a current amplifier circuit by using Q4 which is a common emitter circuit. Output of Q4 is connected to a Relay (Electromagnetic switch), works like a mechanical switch. With the help of a relay it is easy for connecting other electrical appliance.
The relay contact is connected to the power line and hence turns on/off any electrical appliance connected all the way through relay.
Here is a circuit for electronic hobbyists that can switch ON and OFF a light , a fan or a Radio etc…
The sound of clap is received by a small microphone that is shown biased by resistor R1 in the circuit. The signal is further amplified by transistor Q1 ,Q2 ,Q3 . The relay contact is connected to the power line and hence turn ON and OFF any electrical device connected at the output socket .
From the study of CLAP SWITCH , we find that the clap switch system is most important and useful tp us .It is used to turn ON or OFF any electrical circuit by a simple clap eliminating the need to turn the switch ON or OFF manually.