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Difference between Capacitor and Battery

Capacitor and battery both perform the same function of storing and releasing an energy, however, there are essential differences between both of them due to how they function differently. Capacitors store energy in the form of an electric field while batteries store energy in the form of chemical energy.

The most important difference is that Capacitors are fabricated such that Capacitance C stays (just about) constant with changing charge Q (and thus, V linearly depends on Q); on the other hand, batteries are fabricated such that Voltage V stays (just about) constant with changing charge Q.

In this article, the most important differences between Capacitor and Battery are elaborated on the basis of practical factors such as Energy Storage & Behavior, Life Expectancy, Voltage, Supply, Charging & Discharging Behavior, Types, Size, Composition, Charge Holding Capacity, and Applications.This following table covers the key Differences between Capacitor and Battery.

Difference between Capacitor and Battery

Energy StorageEnergy is stored in a chemical formEnergy is stored in an electrical form
LifeRun for longer timeDo not run for longer time
Energy behaviorIt is a source of energy in an electric circuit (acts as an active component)Passive element (stores and release energy)
VoltageProvides relatively constant voltageWhen it discharges, voltage decreases rapidly
SupplyProvides DC ComponentIt is usually used in AC applications and blocks DC Components
TypesAlkaline, lithium-ion, lead acid, zinc-carbonElectrolytic, tantalum, plastic plate, ceramic, mica
Charging & DischargingSlowVery quick
SizeSmallcomparatively Large
CompositionMetals and chemicalsThin metal sheets separated by an insulator
Charging BehaviorCan be charged but will degrade with timeCan be charged over and over without any significant degradation
Charge Holding CapacityCan hold charge for a longer time so can be used as primary energy storage mediumHolds charge for a shorter time thus cannot be used as a primary energy storage medium
ApplicationUse for emergency power, in robots & automobiles, local energy storage, in submarinesUsed extensively in pulsed applications for load sharing, in motor starters, as power back-up for most of the memory functions in various products

About Ahmad Faizan

Mr. Ahmed Faizan Sheikh, M.Sc. (USA), Research Fellow (USA), a member of IEEE & CIGRE, is a Fulbright Alumnus and earned his Master’s Degree in Electrical and Power Engineering from Kansas State University, USA.

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