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SW radio using OP amplifier

Discussion in 'Radio and Wireless' started by aurelZ, Oct 19, 2020.

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  1. Audioguru

    Audioguru

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    Sep 24, 2016
    The LM386 is fairly old and is a single mono amplifier. With a 5V supply its output is inly 0.14W with low distortion into 8 ohms or 0.2W into 4 ohms. It costs $1.02US today. it wastes battery power making heat.

    A modern PAM8403 is a stereo amplifier IC. With a 5V supply each channel produces 1.4W with low distortion into 8 ohms or 2.5W into 4 ohms. It costs $80US today. It stays cool and is very efficient.
     
  2. Harald Kapp

    Harald Kapp Moderator Moderator

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    Nov 17, 2011
    That sure should be 0.80 $?
     
  3. Audioguru

    Audioguru

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    Sep 24, 2016
    I think I wrote $0.80US but my keyboard has its own mind

    Then a much more powerful modern amplifier with 2 channels costs less than the old single channel low power amplifier.
     
  4. aurelZ

    aurelZ

    90
    9
    Jun 10, 2019
    The PAM8403 is a 3W, class-D audio amplifier.
    ... so as such cannot be used as receiver,here is not how much cost than how to build....
     
  5. Harald Kapp

    Harald Kapp Moderator Moderator

    10,591
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    Nov 17, 2011
    It is not meant to be one. It is meant to amplify the signal from a proper receiver.
     
  6. Audioguru

    Audioguru

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    Sep 24, 2016
    He talked about using an old Mickey Mouse "regenerative" detector but did not show it

    Using his very old 741 opamp as a power amplifier to drive an 8 ohm speaker then its 12mA peak output current will be 8.5mA RMS resulting in a very low maximum output power of only 0.0006W. Hold the speaker directly to your ear to faintly hear it.
     
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