Question

To what circuit element is an ideal capacitor equivalent in circuits for which the currents and voltages are constant with time?

Answer 1

Explanation:

Since the current flowing through an ideal capacitor is described by equation:

$i_{C}=C\frac{dV}{dt}$

for voltage across the capacitor constant with time the current is:

$i_{C}=\frac{d(Constant)}{dt}=0$

Open switch has this characteristics (Constant voltage and zero current).