Gain of LM3900

Discussion in 'The Projects Forum' started by Neil Groves, Dec 4, 2011.

  1. Neil Groves

    Thread Starter Member

    Sep 14, 2011
    125
    3
    I have just completed the first stage of my project and have a question regarding the LM3900 chip, on the input i have such a small sinewave it is barely visible with the scope, meanwhile i have a thumping great sinewave on the output pin, it's beautiful!!!

    So what is the gain of the LM3900? it must be huge?

    Neil.
     
  2. SgtWookie

    Expert

    Jul 17, 2007
    22,182
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  3. Audioguru

    New Member

    Dec 20, 2007
    9,411
    896
    That very old LM3900 amplifier is not an opamp, it is different.
    I am surprised that it is still being manufactured.
    Why don't you modify the circuit a little so an ordinary opamp can be used?
     
  4. T.Jackson

    New Member

    Nov 22, 2011
    328
    14
    I am pretty certain that most of these ICs are no longer actually in production. They couldn't be, there is next to zero commercial demand.

    I mean, the preparation work / tool cost to do a run of chips is probably only a few million dollars :eek:

    But 0.0000001 cents a piece after that initial fee.
     
    Last edited: Dec 5, 2011
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