What is a bleeder? Explain its purpose.

1 Answer
Feb 14, 2018

For propose of safety, a bleeder resistor is connected in parallel with the output of a high-voltage power supply circuit. This resistor discharges the electric charge stored in the filter capacitor of the power supply when the load is switched off. Refer to the figure below.
Bleeder resistor provides the following safety features in the electronic power supplies

  1. Acts as a fuse for excess voltage
  2. Discharges the filter capacitors
  3. Removes shock hazards to operating personal from induction coils
  4. Eliminates ground-loop current


The #RC# discharge current flowing through the bleeder resistor, when the equipment is in off state, is called bleeder current. Value of bleeder resistor will depend upon #RC# time constant and how quickly one wants the filter capacitor to be discharged.

EDIT: Corrected circuit

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