# What is a steady state current in a capacitor For what condition is it zero ?

In a capacitor, the steady state current refers to the condition where the rate of change of charge on the capacitor plates becomes zero over time. This means that once the capacitor is fully charged (or discharged), the current flowing into or out of the capacitor ceases to exist. In other words, the steady state current in a capacitor is zero under conditions where the voltage across the capacitor remains constant.

The current through a capacitor is zero in steady state because capacitors block direct current (DC). Once the capacitor reaches steady state, it behaves like an open circuit to DC current. This occurs because the capacitor charges up to the applied voltage, creating an electric field between its plates that opposes any further flow of charge carriers (electrons or holes). As a result, no current flows through the capacitor once the voltage across it stabilizes.

Steady current in a capacitor refers to the absence of current flow through the capacitor after it has reached equilibrium. Initially, when a voltage is applied across a capacitor, current flows as the capacitor charges or discharges. However, as the capacitor voltage stabilizes (reaches steady state), the current through the capacitor drops to zero. At steady state, the capacitor essentially acts as an open circuit for DC current, although it can still pass alternating current (AC) depending on its frequency and the circuit configuration.

The condition of steady state in a capacitor occurs when the voltage across the capacitor terminals remains constant over time. This typically happens after a transient period where the capacitor charges or discharges. During steady state, the voltage does not change significantly, and consequently, the current through the capacitor becomes negligible or zero. This condition is essential in electronic circuits where capacitors are used for energy storage, filtering, or timing, ensuring stable operation once the initial charging or discharging phase is complete.

At steady state, the current through a capacitor is zero for a DC (direct current) condition. Once the capacitor has fully charged or discharged to the applied voltage, no more current flows into or out of the capacitor in a steady state DC circuit. This is because the capacitor has reached equilibrium with the voltage source, and its plates have accumulated the maximum charge allowed by the applied voltage. In AC (alternating current) circuits, the current through a capacitor at steady state depends on the frequency of the AC signal and the impedance of the circuit, but for DC conditions, it remains zero once equilibrium is reached.