self bias

Discussion in 'General Electronics Chat' started by abhinavsri2004, Apr 19, 2007.

  1. abhinavsri2004

    Thread Starter New Member

    Apr 19, 2007
    can anyone tell me what is self biasing of transistors.
  2. mozikluv

    AAC Fanatic!

    Jan 22, 2004

    it is simply placing the bias resistor between the collector and the base. this way feedback voltage is fed from the collector to the base w/c in effect develops a forward bias.

    say if there is an increase in temp. there will also be a corresponding increase in collector current. becoz of the bias resistor, the collector voltage will fall due to the voltage increased w/c had develop across the load resistor. this voltage drop goes to the base resulting in a reduced base current effectively opposing the increase in collector current. vice versa will happen when the collector current decreases.

    one major drawback of this circuit is it can be effectively used only when temperature change does not vary widely.