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Amplify volume from emic module — Parallax Forums

Amplify volume from emic module

timextimex Posts: 21
edited 2008-10-03 23:51 in General Discussion
Hello, every1.

My emic module's volume is not loud enough for the project I'm implementing. Can any1 please help me out. I need a functional amplification circuit. Thanks

Comments

  • LeonLeon Posts: 7,620
    edited 2008-09-29 22:22
    I like the TDA7052 for that sort of thing.

    Leon

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Amateur radio callsign: G1HSM
    Suzuki SV1000S motorcycle
  • timextimex Posts: 21
    edited 2008-09-30 11:39
    Can you please expantiate
  • LeonLeon Posts: 7,620
    edited 2008-09-30 13:37
    It's a very good little amplifier chip with very few external components required.

    Leon

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Amateur radio callsign: G1HSM
    Suzuki SV1000S motorcycle
  • Mike GreenMike Green Posts: 23,101
    edited 2008-09-30 13:49
    The LM386 is another simple amplifier that works in this application. It's sold by RadioShack, so it's readily available and there's plenty of sample circuits and other information on the web that you can find with a simple web search for "LM386".
  • timextimex Posts: 21
    edited 2008-09-30 14:26
    alright, thanks. i'll look for LM386.
  • LeonLeon Posts: 7,620
    edited 2008-09-30 18:24
    The TDA7052 is a much better device than the LM386 - less noisy, less distortion and uses fewer components.

    Leon

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Amateur radio callsign: G1HSM
    Suzuki SV1000S motorcycle
  • Mike GreenMike Green Posts: 23,101
    edited 2008-09-30 19:28
    It is a much better device, but, if I just want one of them and I don't need much else, I can usually pick up an LM386 at a RadioShack I can bike to or easily drive to and I like to encourage them to stock some basic parts
  • timextimex Posts: 21
    edited 2008-10-01 21:55
    How will pin2 of the TDA7052 be connected to the Aout pin of emic? Is there any other consideration one has 2 make?

    Thanks
  • Mike GreenMike Green Posts: 23,101
    edited 2008-10-01 22:10
    The documentation for the EMIC says for Aout:
    Audio output buffer pin provides a single-ended analog output of the
    synthesized speech for external amplification. Drives a minimum load of
    5k Ω up to a maximum of 1Vp-p. The AC signal is superimposed on
    approximately 1.2VDC bias and must be capacitively coupled to the
    load.
    If you read the datasheet for the TDA7052, the sample circuit shows a load of 5K.
    So, you need to capacitively couple Aout to pin 2 of the TDA7052. I'd use a 1uF to
    10uF 8-10V minimum electrolytic with the + end to Aout. I'd put a volume control
    between the electrolytic and pin 2, like a 5K or 10K trim pot with one end to ground,
    the other end to the electrolytic, and the slider to pin 2 of the TDA7052.
    I'm sure others may have better ideas, but this is what I'd start with.
  • timextimex Posts: 21
    edited 2008-10-03 15:13
    I wired the circuit exactly as u described above using TDA7052. It works perfectly. Infact the sound volume is exactly what I wanted. Using the 10Kohm trim pot, the volume can be increased or decreased. Thanks a lot for your assistance
  • LeonLeon Posts: 7,620
    edited 2008-10-03 23:51
    That's how I use them. They work very well with headphones, as well.

    Leon

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Amateur radio callsign: G1HSM
    Suzuki SV1000S motorcycle
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