reason for clamping the output for reactive loads?

Discussion in 'General Electronics Chat' started by erumai, Jan 6, 2009.

  1. erumai

    Thread Starter New Member

    Sep 28, 2007
    4
    0
    Hi friends,

    Many of the power amplifier circuits for reactive loads, have their output clamped through diodes to the power supply of amplifier. Can anyone of you explain the reason behind this?

    I tried searching in google and got some vague explanations relating it to the phase difference between voltage and current in the load, which may cause the peak current to flow at zero voltage. But I am unable to get the logic behind this.

    thanks and regards
     
  2. DickCappels

    Moderator

    Aug 21, 2008
    2,648
    632
    In a nutshell:

    If you drive an inductor from a voltage supply, such as when you saturate a transistor, current will flow through the indluctor. When you disconnect the inductor from the voltage supply, such as when a transistor switches off, the magnetic field in the inductor will begin to collapse, causing the voltage across the inductor to increase. Sometimes, the voltage can get high enough to cause a transistor to break down (or avalanche) and if there is enough energy stored in the inductor, the transistor can experience premanent damage.
     
  3. erumai

    Thread Starter New Member

    Sep 28, 2007
    4
    0
    Hi Dick..thanks for the reply..I got it..
     
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