Charged Capacitor: Is Disconnecting Dangerous?

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    Capacitor Charged
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Discussion Overview

The discussion revolves around the safety concerns related to disconnecting charged capacitors in electronic circuits, particularly in comparison to inductors. Participants explore whether it is necessary to provide a discharge path for charged capacitors and the implications of doing so.

Discussion Character

  • Debate/contested

Main Points Raised

  • One participant references a video suggesting that it is dangerous to disconnect a charged inductor without providing a current path and questions if the same applies to charged capacitors.
  • Another participant shares personal experience with high-voltage power capacitors from vacuum tube equipment, indicating that they can retain charge and pose a shock hazard even after disconnection.
  • A different viewpoint argues that it is not necessary to provide a path for a charged capacitor, stating that the purpose of charging a capacitor is often to store energy for future use.
  • One participant warns about the risks involved in repairing power supplies, noting that while many large capacitors self-discharge, some can retain high voltages for extended periods.

Areas of Agreement / Disagreement

Participants express differing views on whether a discharge path is necessary for charged capacitors, indicating that the discussion remains unresolved with multiple competing perspectives.

Contextual Notes

There are assumptions regarding the behavior of capacitors and inductors that are not fully explored, such as the conditions under which capacitors retain charge and the specifics of energy storage in inductors.

Bruno Tolentino
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In this video:



exactly in the 7:05, the narrator says that is dangerous to charge the inductor and disconnect it of the circuit and that is necessary provide anoter path for the current flow. The same phenomenon happens with a charged capacitor too? Is necessary provide a path for a charged capacitor, otherwise, there will be problem?
 
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Bruno Tolentino said:
The same phenomenon happens with a charged capacitor too?
Back in the days of vacuum tubes, the power capacitors usually were charged up to 400 volts - and they self-discharged pretty slowly. So, even if you pulled the plug, you could get quite a jolt when trying to repair the equipment.

So - yes, when fiddling around in electronics, discharging capacitors through a limiting resistor seems a good idea.
 
I believe the answers to your questions are No and No... It is not the same phenomenon and it is not necessary to provide a path to a charged capacitor, in fact, often times that's the whole point to charge a capacitor and leave it charge for future use.
The reason why it takes energy to pump current through an inductor is because your are exciting the electromagnetic field, but the inductor by itself does not have the ability to keep it and so at the end of operation of your device this energy will always tend to come back out and so you need to provide a path.
 
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Just be very careful if you ever have to repair a power supply. Fortunately most large capacitors are "leaky" and will self discharge but not all. Some will retain quite high voltages for a long time after being switched off.
 
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