Question
What is the purpose of connecting equal-value resistors across power supply filter capacitors connected in series?
Answer Options
- A) Equalize the voltage across each capacitor
- B) Discharge the capacitors when voltage is removed
- C) Provide a minimum load on the supply
- D) All these choices are correct
Correct Answer: D
Explanation
When multiple power supply filter capacitors are connected in series (often done to achieve a higher total voltage rating), each capacitor in the chain can have slightly different actual capacitance and internal leakage resistance. This difference can cause the voltage across the capacitors to become unequal, potentially over-volting and destroying the capacitor with the lowest capacitance.
Connecting equal-value ‘bleeder’ resistors across each capacitor serves multiple purposes: first and foremost, they act as a voltage divider to force equalize the voltage across each capacitor; second, they provide a path to safely discharge the capacitors when voltage is removed (a crucial safety function); and third, they provide a minimum load on the supply. Therefore, All these choices are correct.
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