Difference between Battery and Capacitor

DifferencesDigital ElectronicsElectronics & Electrical

Both Battery and Capacitor seem to be similar in the first glance because they store and release the electric energy, but there are many differences between them which we are going to highlight in this article.

One of the most significant differences between a battery and a capacitor is that a battery stores electrical energy in the form of chemical energy and again converts it into electrical energy when required, while a capacitor stores electrical energy in the form of electrostatic field.

What is a Battery?

A battery is a device which is used as the source of energy in electrical and electronic circuits to provide necessary excitation. A typical battery has three fundamental parts viz. positive terminal called cathode, negative terminal called anode and an electrolyte.

A battery stores the electric charge (or electrical energy) in the form of chemical energy and converts it back to the electrical energy when required. Inside the battery, the chemical reaction called redox (oxidation and reduction) takes place between the cathode and anode through the electrolyte during charging and discharging of the battery.

What is a Capacitor?

A capacitor is a device which is also used as an energy storing element in the electrical and electronic circuits. A capacitor is a two terminal device consists of two parallel plates separated by a dielectric material such as mica, paper, etc.

When a voltage is applied across the plates of a capacitor, it starts storing the electrical energy in the electrostatic field. The property of a capacitor by which it stores the electrical energy is known as capacitance. The capacitor stores electrical energy by holding apart pairs of opposite charges between its plates. The capacitors have many applications in electrical and electronic circuits such as memories, filters, compensators, etc. Difference between Battery and Capacitor

The following table highlights the major differences between a battery and a capacitor −

Basis of DifferenceBatteryCapacitor
DescriptionA battery a device which stores the electric charge in the form of chemical energy and converts it back in the electrical energy when needed.A capacitor is a two terminals passive electronic component which stores the electric charge in the electrostatic field and release it back to the circuit as electrical energy.
Symbol
ConstructionA typical battery has three main parts viz. a positive terminal (cathode), a negative terminal (anode) and an electrolyte.A capacitor is a two terminal device consists of two metallic plates separated by a dielectric material such as air, mica, paper, etc.
Principle of operationThe operation of a battery is based on the chemical reaction, called redox reaction (oxidation-reduction reaction). These reactions takes place during charging and discharging of the battery.The operation of a capacitor is based on the principle of electrostatic, i.e. when a voltage is applied to a capacitor, it starts to store energy in it.
Element typeA battery is an active element as it supplies energy to the circuit.A capacitor is passive circuit element because it cannot produce energy for infinite amount of time. In simple word, it cannot supply energy to the circuit.
FunctionThe primary function of a battery in an electrical or electronic circuit is to provide energy to the circuit. Also, a battery can generate electric charge.The capacitor only stores the electric charge or electrons.
Behavior with AC & DCA battery stores and produces only direct current (DC). AC cannot be used to charge a battery and the battery cannot produce AC.A capacitor blocks direct current (DC) and allows to pass alternating current (AC).
TypesThere are various types of batteries available such as Alkaline battery, Lithium ion battery, Silver oxide battery, Nickel cadmium battery, Nickel metal hydride battery, etc.There are many types capacitors available like ceramic capacitor, mica capacitor, paper capacitor, electrolytic capacitor, electrochemical capacitor, super capacitor, hybrid super capacitor, tantalum integrated capacitor, etc.
VoltageA battery provides a constant voltage while discharging.The voltage across a capacitor decreases rapidly while discharging.
Energy densityBattery has better energy density as compared to capacitor.For a capacitor, the energy density is lower than a battery.
Terminal polarityFor a battery, the polarity of terminals is reversed during charging and discharging.In case of capacitor, the terminal polarity remains the same during charging and discharging.
Charging and discharging timeThe charging and discharging time of a battery is very high, typically, 20 to more than 60 minutes.The charging and discharging time of a capacitor is very less, typically it is 1 to 10 seconds.
Life spanA battery has relatively smaller life span which is about 5 to 10 years.The lifespan of a capacitor is about 10 to 15 years which is comparatively more than a battery.
Size (for same capacity)A battery is smaller than a capacitor.A capacitor has lager size as compared to a battery.
CostBattery is expensive than a capacitor.The cost of a capacitor is less.
ApplicationsBatteries are widely used as power source in various electronic devices such as torch, radio, toys, military and submarine appliances, automotive vehicles, backup power supplies, etc.Capacitor is used in electrical and electronic circuit to introduce capacitance, some uses capacitors are as filters, power factor correction, motor starters, coupling and decoupling of signals, oscillators, etc.

Conclusion

Both battery and capacitor are energy-storing elements used in electrical and electronics engineering. However, these two devices are different in many aspects such as their construction, purpose, working principle, cost, and many more.

raja
Updated on 28-Jun-2022 06:55:40

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