Difference between Capacitor and Supercapacitor

Differences Digital Electronics Electronics & Electrical

Both capacitor and supercapacitor are passive circuit components that store electrical energy in the form of electrostatic charge. Thus, the primary function of capacitor and supercapacitor is the same, i.e., storage of electric charge. However, there are many difference between a capacitor and a supercapacitor.

In this article, we will discuss the key differences between capacitor and supercapacitor by considering various parameters such as definition, construction, types, energy density, etc. But before that we should learn the basics of capacitor and supercapacitor so that it becomes easier to understand the differences.

What is a Capacitor?

A capacitor is a two terminal passive circuit element that can store electrical energy in the form of electrostatic charge. It consists of two conducting plates separated by a material called dielectric. The two conducting wires are connected to the metal plates called terminals of the capacitor.

When a voltage is applied to the capacitor, an electric field established between the plates of the capacitor polarizes the dielectric material, and hence the capacitor is said to be charged. The capacitor is one of the most fundamental circuit component of any electrical or electronic circuit.

What is a Supercapacitor?

A supercapacitor, also known as ultra-capacitor, is a capacitor having a capacitance value much greater than that of an ordinary capacitor. However, the capacitance value of the supercapacitor is very high but it has lower voltage limits.

The basic principle of the operation of a supercapacitor is the same as that of a conventional capacitor. The supercapacitor uses electrodes of much larger surface area.

Generally, a supercapacitor have electrodes that are coated with active carbon as electrode material. The supercapacitor uses a separator between its electrodes instead of a dielectric material.

Basically, the separator is an ion permeable membrane that can provide insulation and exchange of ions of electrolyte between the electrodes.

Difference between Capacitor and Supercapacitor

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

Basis of Difference	Capacitor	Supercapacitor
Definition	A capacitor is a passive circuit element that can store electrical energy in the form of electrostatic charge.	A type of capacitor with very high capacitance value and low voltage rating, and stores the charge in it, is known as supercapacitor.
Construction	A capacitor is constructed by separating two conducting plates by a dielectric medium.	Supercapacitor is constructed by separating two conducting plates by a separator (an electrolytic solution) instead of dielectric.
Electrodes	The electrodes of a capacitor are made up of a metallic conductor.	Supercapacitor consists of activated carbon coated electrodes.
Mechanism of energy storage	The electrical energy in a capacitor is stored electrostatically only.	A supercapacitor stores electrical energy either electrostatically or electrochemically or hybrid.
Dielectric material	The common dielectric materials used between the plates of a capacitor are ceramic, polymers, mica, paper, or aluminium oxides, etc.	Supercapacitor consists of activated carbon between its electrodes. When an electric field is applied to the material, a double electric field is produced which acts as a dielectric in the supercapacitor.
Types	Based on the dielectric material used, the common types of capacitors are − electrolytic capacitors, film capacitors, paper capacitors, ceramic capacitors, etc.	The types of supercapacitors are: electrostatic double layer capacitors, electrochemical pseudo-capacitors and hybrid supercapacitors.
Capacitance value	A capacitor has low capacitance value.	A supercapacitor has relatively high capacitance value.
Voltage rating	The voltage rating of a capacitor is high.	Supercapacitors have relatively lower voltage ratings.
Energy density in Wh/kg	The energy density for a capacitor is relatively low. Generally, lies between 0.01 Wh/kg to 0.05 Wh/kg.	Supercapacitors have comparatively very high energy density. Usually, ranges from 1 Wh/kg to 5 Wh/kg.
Charging & discharging times	The charging and discharging times for a capacitor range from picoseconds to milliseconds.	The charging and discharging times of a supercapacitor vary from milliseconds to seconds.
Operating temperature	For a capacitor, the operating temperature is about -20 °C to +100 °C.	The operating temperature for supercapacitors is about -40 °C to +85 °C.
Form factor	The form factor of capacitors is small to large.	Supercapacitors have small form factor.
Cost	Capacitors are cheaper.	The cost of supercapacitors is high.
Applications	Capacitors are used in power factor correction, filter circuits, coupling and decoupling of signals, motor starter circuit, oscillators, etc.	Supercapacitors are widely used in UPS, RAM, CMOS, laptops and other handheld devices to stabilize the power supply, LED flashlights of digital cameras, etc.

Conclusion

We have listed all the major differences between capacitor and supercapacitor in the above table. The most significant difference between a capacitor and a supercapacitor is that a capacitor has low capacitance value and high voltage rating, whereas a supercapacitor has high capacitance value and low voltage rating.