quiescent current

Discussion in 'The Projects Forum' started by crazyeye, Mar 10, 2009.

  1. crazyeye

    Thread Starter New Member

    Mar 10, 2009
    2
    0
    hello.. I am new in here...

    I have a question about quiescent current for power amplifier... we all know that DC offset should be within +/- 25mV.

    my question is what is the recommended quiescent current for amplifier? how do I measure it by using a multimeter?
     
  2. mik3

    Senior Member

    Feb 4, 2008
    4,846
    63
    This depends on the class (A, AB, B, C, etc) of the amplifier.
    An ideal amplifier should only draw current with the present of an input signal. Thus you try to reduce the quiescent current as much as you can.
     
  3. crazyeye

    Thread Starter New Member

    Mar 10, 2009
    2
    0
    typically for a class AB amps,

    in my circuit the minimum voltage across the emitter resistor of driver transistor is 150mV going to the base of power output transistor.

    when I measure the voltage between Vbe of OPt it is also 150mV,
    so I try to adjust the bias servo so that i can get a reading of 300Mv across the emitter resistor of driver transistor, but the Vbe also read the same reading of 300mV.

    what is the problem?
     
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