If there is no current through a capacitor is the voltage drop zero?

 

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.

 

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.

 

kduubyah,

If there is no current through a capacitor is the voltage drop zero?

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,

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

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

Ratch