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    An electronic stethoscope is used to listen to your heartbeat and you would normally use a listening tube or stethoscope. This electronic stethoscope circuit uses a piezo sounder from a musical greetings card or melody generator, as a microphone. This transducer has an output signal in the order of 100 mV and its low frequency response is governed by the input impedance of the amplifier.

    For this reason we have chosen to use an emitter follower transistor amplifier. This has a high input impedance and ensures that the transducer will have a very low frequency response. At the output you just need to connect a set of low impedance headphones to be able to listen to your heartbeat.

    Replacing the emitter follower with a Darlington transistor configuration will further increase the input impedance of the amplifier.

    Electronic Stethoscope Circuit diagram

    electronic stethoscope circuit schematic

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    10 Responses to "Electronic Stethoscope Circuit"

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    1. legishkrishnan says: on December 5, 2009 at 6:22 am

      can we add a thermistor to this circuit so that both heart rate and temperature can be detected at the same time ………..

    2. Use a FET and the input impedance can be even higher.

    3. hola alparecer son buenos en la tecnologuia me interesa charlar con ustedes si pueden aveces las eramientas es nesesaria para poder acer las cosas

    4. Su proyecto suena muy bien para mi, yo los apoyo, ayudemonos a tener muchos diagramas disponibles. Pero por favor no empiezen a cobrar por esto !
      Your project sound very good to me, I will support you, let’s help ourselves to have lots of diagrams available. But please don’t start charging for this !

    5. good cicuit

    6. what is BZ1 BUZER or condensr mic ??
      thanks

    7. please mention actual working of this circuit..

    8. saranyakrishnan4@gmail.com says: on August 21, 2012 at 9:00 am

      give the abstract

    9. What is the meaning of {BZ1} is a condmic or buzzer..or whatever let me know thanks author

    10. en realidad sus proyectos y circuitos son muy interesantes,y a la vez didácticos ,los felicito

      Miguel Mujica

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