# Why does the current into a capacitor stop when it's fully charged?

I am a newbie at electronics and I want to ask when the capacitor is fully charged why the current is stopped.

• flow into your car's gas tank stops when the nozzle clicks because the tank is full; how would anything flow into a full tank? Commented Nov 18, 2023 at 21:34

When there's a potential difference between two nodes there's a current flow. The amount of current is set by the resistance across these nodes.

When there's no potential difference, no current flows.

• if I want to discharge the capacitor, what should i do? Commented Nov 18, 2023 at 14:15
• @ElectroNoob you need to create a discharge path i.e. a resistor (or load, in general) connects to a lower potential. Practically, if you cut the battery connection and connect a resistor across the capacitor it's going to be enough. Commented Nov 18, 2023 at 14:18

It is the nature of the capacitor. There can be current through the capacitor only if the voltage across it is changing.

The defining equation is:

$$i_C=C\frac{dv_C}{dt}$$

• oh I see, thanks for the answer Commented Nov 18, 2023 at 14:30