In summary, the absence of current flow in a capacitor in steady state is a consequence of the capacitor reaching a fully charged condition where the voltage remains constant. The capacitor’s capacitance prevents the flow of direct current, making it act as an open circuit to DC in the steady state.
In steady state, a capacitor does not allow a direct current (DC) to flow through it due to its inherent electrical properties and the nature of the charging process. To comprehend this behavior, one must delve into the working principles of capacitors and the characteristics of DC circuits.
As this constitutes an open circuit, DC current will not flow through a capacitor. If this simple device is connected to a DC voltage source, as shown in Figure 8.2.1 , negative charge will build up on the bottom plate while positive charge builds up on the top plate.
Given a fixed voltage, the capacitor current is zero and thus the capacitor behaves like an open. If the voltage is changing rapidly, the current will be high and the capacitor behaves more like a short. Expressed as a formula: i = Cdv dt (6.1.2.5) (6.1.2.5) i = C d v d t Where i i is the current flowing through the capacitor,
If this simple device is connected to a DC voltage source, as shown in Figure 8.2.1 , negative charge will build up on the bottom plate while positive charge builds up on the top plate. This process will continue until the voltage across the capacitor is equal to that of the voltage source.
Electrical current affects the charge differential across a capacitor just as the flow of water affects the volume differential across a diaphragm. Just as capacitors experience dielectric breakdown when subjected to high voltages, diaphragms burst under extreme pressures.