# Voltage across a capacitor

Discussion in 'Homework Help' started by kduubyah, Nov 17, 2009.

1. ### kduubyah Thread Starter New Member

Nov 15, 2009
1
0
If there is no current through a capacitor is the voltage drop zero?

2. ### t_n_k AAC Fanatic!

Mar 6, 2009
5,448
782
Not necessarily - a charged capacitor will hold charge (and thereby have a potential difference across its terminals) even if isolated or disconnected from the circuit which initially provided the charge to it.

3. ### JDT Well-Known Member

Feb 12, 2009
658
85
Or to put it another way: Current will only flow "through" a capacitor when the voltage across its plates is changing.

Actually, the current does not flow through, it charges (or discharges) the capacitor.

4. ### Ratch New Member

Mar 20, 2007
1,068
3
kduubyah,

Current never exists through a capacitor, unless it is leaky. Current exists up to one plate of a capacitor, and it exists away from the opposite plate, but never through the capacitor. It does this by accumulating charge on one plate, and depleting charge on the opposite plate. This causes a charge imbalance to form, thereby causing a voltage difference between the capacitor plates.

JDT,

Charge never flows and current never exists through a capacitor under any circumstances unless it is leaky. See ahove

Ratch