Capacitor and inductor fall under the category of passive components which store and release the energy but do not consume it. Both of the components are extensively used in several applications related to AC systems, especially in signal filtering.
The main difference between the capacitor and the inductor is that capacitor opposes an abrupt change in voltage (dV/dt) whereas inductor opposes an abrupt change in current (dI/dt). Furthermore, capacitor stores energy in the form of an electric field (voltage-dependent:$\frac{1}{2}C{{V}^{2}}$) whereas an inductor stores energy in the form of a magnetic field (current dependent: $\frac{1}{2}L{{I}^{2}}$ ).
This article is intended to cover the main differences between Capacitor and Inductor on the basis of Units, Types, Energy Storage and Calculation, DC Behavior, Current Flow, Reactance Calculation, Phasor Diagram, Series & Parallel Connections, and Applications.This following table conveys the main Differences between Capacitor and Inductor.
Difference Between Capacitor and Inductor
Characteristics | Capacitor | Inductor |
Unit | Farad (F) (most commonly used units are μF, pF ) | Henry (H) (most commonly used unit is mH) |
Types | Ceramic, tantalum type, electrolyte, mica | Multilayer, ceramic core, coupled inductor |
Voltage Vs Current | Voltage lags behind Current by 90 o for pure capacitor | Current lags behind Voltage by 90 o for pure inductor |
Energy storage | In the form of Electric Field | In the form of Magnetic field |
DC Behavior (frequency = 0 Hz) | Open circuit for DC Component (${{X}_{C}}=\frac{1}{2\pi fC}$ ) because of Infinite reactance | Short Circuit for DC Component (${{X}_{C}}=2\pi fL$ ) because of Zero reactance |
Energy Calculation | Energy is calculated as: $\frac{1}{2}C{{V}^{2}}$ | Energy is calculated as: $\frac{1}{2}L{{I}^{2}}$ |
Use as a Filter | Dominant element in high pass filters | Dominant element in low pass filters |
Current flow | No current flows through the plates | Current flows through the coil |
Reactance Calculation | ${{X}_{C}}=\frac{1}{2\pi fC}$ | ${{X}_{C}}=2\pi fL$ |
Resistance to change in Voltage & Current | It opposes abrupt change in voltage (${}^{dV}/{}_{dt}$ ) | It opposes abrupt change in voltage (${}^{dI}/{}_{dt}$ ) |
Phasor Diagram | | |
Series/Parallel Connection | Summing up capacitors in parallel is same as resistors addition in series &
Summing up capacitors in series is same as resistors addition in parallel | Summing up inductors in parallel is same as resistors addition in parallel &
Summing up inductors in series is same as resistors addition in series |
Applications | Extensively used in power supplies to smooth the output of a rectifier, and for power factor correction in electrical power systems | Extensively used in TV, Radio, Transformers, and as a current limiter |