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

    opamps

    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.
    v(id)=V1-V2
    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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