operational amplifiers

Discussion in 'Electronics Forum' started by Guest, Jun 8, 2007.

  1. Guest

    Guest Guest

    I need help on the theory behind the voltages on an op-amps negative and positive terminal.

    Why does the positive and negative terminals must have equal voltages?
  2. Guest

    Guest Guest


    infinite gain is one of the ideal characterestics of op-amps.(so that it can amplify even the very weak signal.)
    As the basic building block of opamp is differential amplifier, it amplifies the difference b/w the signals applied at the two terminals.
    so.. the gain would be..
    gain=v(out)/ v(id)=infinity
    where v(out) is o/p voltage and v(id) is voltage difference b/w two terminals .
    for the gain tobe infinite.. denominator should be zero..i.e., the difference b/w two terminal voltages should be zero..that's why the voltages at two terminals must be equal.. while treating for ideal case.
    vid=0=> V1=V2
  3. Guest

    Guest Guest

    Two voltage power supplies having negative outputs with respect to common are combined to give positive as well as negative output with respect to common base . An operational preamplifier is always used as an inverter. The combination includes provision for programming by means of a voltage returned to common making the system compatible with Conventional remote control systems.

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