What happens with a discharge resistor in a capacitive circuit

Capacitors need to discharge.

A capacitor will hold its charge indefinitely once it has built it up.

This can make them very useful (tasers, defibrillators) but also very dangerous.

For this reason they must be given a safe path to discharge through.  This is why we use a 2 pole selector switch with a discharge resistor.

It is important to view the discharge circuit as something completely different than the charging circuit.

In the capacitor is discharging it acts like a source that is draining very quickly.  If it is a source the voltage across the resistor ends up being the same value as the capacitor.

When determining the time it takes to discharge the capacitor it is also important to use the R value of the discharge resistor, not the original resistor.

The video goes through a complete walk through of the process.

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