Study › Amateur Extra › E7D › E7D14

E7D14

PRACTICAL CIRCUITS · Power supplies and voltage regulators; solar array charge controllers

E7D14E7D →

What is the purpose of connecting equal-value resistors across power supply filter capacitors connected in series?

  1. AEqualize the voltage across each capacitor
  2. BDischarge the capacitors when voltage is removed
  3. CProvide a minimum load on the supply
  4. DAll these choices are correct
Why When electrolytic capacitors are stacked in series to withstand a high DC rail, their individual leakage currents differ, so without help the voltage would divide unevenly and one capacitor could exceed its rating. Equal-value resistors across each capacitor swamp that leakage and force the voltage to split evenly. The same resistor string doubles as a bleeder, draining the stored charge after the supply is switched off so the capacitors are safe to touch, and it also presents a small permanent load that keeps the supply voltage from soaring under no-load conditions.
Watch out Each single-purpose choice is true on its own, so picking just the equalizing function or just the bleeder function misses the other jobs the same resistors perform; the pool wants all three.
One resistor string, three jobs: equalize, bleed, load. When several separate answers are all true, take the all-of-these choice.
HamSandwich explanation, first draft. The question and answers are the NCVEC text.
← E7D13 All of E7D E7D15 →

The rest of E7D

  1. E7D01 How does a linear electronic voltage regulator work?
  2. E7D02 How does a switchmode voltage regulator work?
  3. E7D03 What device is used as a stable voltage reference?
  4. E7D04 Which of the following describes a three-terminal voltage regulator?
  5. E7D05 Which of the following types of linear voltage regulator operates by loading the unregulated voltage source?
  6. E7D06 What is the purpose of Q1 in the circuit shown in Figure E7-2?
  7. E7D07 What is the purpose of C2 in the circuit shown in Figure E7-2?
  8. E7D08 What type of circuit is shown in Figure E7-2?
  9. E7D09 How is battery operating time calculated?
  10. E7D10 Why is a switching type power supply less expensive and lighter than an equivalent linear power supply?
  11. E7D11 What is the purpose of an inverter connected to a solar panel output?
  12. E7D12 What is the dropout voltage of a linear voltage regulator?
  13. E7D13 Which of the following calculates power dissipated by a series linear voltage regulator?
  14. E7D14 What is the purpose of connecting equal-value resistors across power supply filter capacitors connected in se…
  15. E7D15 What is the purpose of a step-start circuit in a high-voltage power supply?
MFJ-259D HF/VHF Antenna AnalyzerSponsored · View on Amazon →Baofeng UV-5R Dual Band Two Way RadioSponsored · View on Amazon →