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What is a capacitor and how it works? Ceramic - Electrolytic – Tantalum - Supercapacitor
What is a capacitor and how it works? Ceramic - Electrolytic – Tantalum - Supercapacitor
The capacitor is a component that stores an electric charge, as a battery would, but has a different operation and use.
We can find them in all circuit boards and they are very useful because they can release energy when the main electrical supply gets interrupted or is unstable.
In this video we go through every secret of capacitors.
JAES Company offers every type of capacitor from its portfolio and has been working as industrial supplier for more than 10 years.
In this basic circuit we can see a light-bulb connected to a battery and a switch to turn it on and off. If we switch the light on and off repeatedly, the light-bulb will flash because at times it gets no power from the battery.
But if we add a capacitor into the circuit, it intervenes briefly when we turn off the power, maintaining the light-bulb on for a while; this means that if we switch the light on and off repeatedly, the light-bulb will be always on.
Let’s see how it’s made:
A capacitor is usually composed of two metal conductive foils, separated by dielectric insulating material.
A dielectric material is an insulator unable to conduct electricity, because it will polarise on the opposite pole when an electric field passes through it, showing the property called dielectricity.
In the circuit, while electrons of the battery flow from the negative pole into the light-bulb turning it on, a part of them accumulates in the foils of the capacitor they’re connected to, charging negatively that side like the battery.
The other foil will lose its electrons, which are flowing into the positive pole of the battery, like the ones coming from the light-bulb; that side of the capacitor will charge positively like the battery.
The electric charge is then stored on the surface of the conductors, on the edge in contact with the dielectric, and the same tension of the battery in Volt.
Electrons can’t go through the capacitors, like they do with the light-bulb, because the dielectric insulating material doesn’t allow it; besides, the electrons on the negative pole are attracted by positively charged atoms of the positive pole. This attraction is just a simple electric field and keeps electrons accumulated in the capacitor.
Now, if we interrupt the power of the battery, the electrons of the negative pole of the capacitor run in place of the battery’s ones maintaining the light-bulb on, and continue till they reach the positive pole of the capacitor. As electrons are balanced, the voltage between the two conductors is 0 and the electric current stops to flow.
If we connect the battery power again, the capacitor recharges and the light-bulb stays on.
Hence the capacitor allows us to keep the most constant electrical supply level available if the principal power is irregular.
In this clip we can experience what we’ve just learned: as we can see, this electrolytic capacitor can store enough energy to hold the LED on for a while after having unplugged the battery.
There are several types of capacitors, and each type has two fundamental data to be identified: the voltage and the electrical capacitance.
The voltage, or rather the electric potential difference, is measured in Volt with the symbol V; it indicates the maximum value the capacitor can bear.
The electrical capacitance, instead, is indicated with the letter C, and its value is the ratio between the charge Q and the potential V. In the system of units it is the ratio Coulomb/Volt called Farad with symbol F.
Its name is due to the physicist Michael Faraday, and one Farad is an huge measure compared to the capacity of a standard capacitor, that’s why we use submultiples: microfarad “µF” or the picofarad “pF”.
The farad is directly proportional to the area of the conductive foils, inversely proportional to the distance between them, and depend on the type of dielectric insulating material.
We can find them in all circuit boards and they are very useful because they can release energy when the main electrical supply gets interrupted or is unstable.
In this video we go through every secret of capacitors.
JAES Company offers every type of capacitor from its portfolio and has been working as industrial supplier for more than 10 years.
In this basic circuit we can see a light-bulb connected to a battery and a switch to turn it on and off. If we switch the light on and off repeatedly, the light-bulb will flash because at times it gets no power from the battery.
But if we add a capacitor into the circuit, it intervenes briefly when we turn off the power, maintaining the light-bulb on for a while; this means that if we switch the light on and off repeatedly, the light-bulb will be always on.
Let’s see how it’s made:
A capacitor is usually composed of two metal conductive foils, separated by dielectric insulating material.
A dielectric material is an insulator unable to conduct electricity, because it will polarise on the opposite pole when an electric field passes through it, showing the property called dielectricity.
In the circuit, while electrons of the battery flow from the negative pole into the light-bulb turning it on, a part of them accumulates in the foils of the capacitor they’re connected to, charging negatively that side like the battery.
The other foil will lose its electrons, which are flowing into the positive pole of the battery, like the ones coming from the light-bulb; that side of the capacitor will charge positively like the battery.
The electric charge is then stored on the surface of the conductors, on the edge in contact with the dielectric, and the same tension of the battery in Volt.
Electrons can’t go through the capacitors, like they do with the light-bulb, because the dielectric insulating material doesn’t allow it; besides, the electrons on the negative pole are attracted by positively charged atoms of the positive pole. This attraction is just a simple electric field and keeps electrons accumulated in the capacitor.
Now, if we interrupt the power of the battery, the electrons of the negative pole of the capacitor run in place of the battery’s ones maintaining the light-bulb on, and continue till they reach the positive pole of the capacitor. As electrons are balanced, the voltage between the two conductors is 0 and the electric current stops to flow.
If we connect the battery power again, the capacitor recharges and the light-bulb stays on.
Hence the capacitor allows us to keep the most constant electrical supply level available if the principal power is irregular.
In this clip we can experience what we’ve just learned: as we can see, this electrolytic capacitor can store enough energy to hold the LED on for a while after having unplugged the battery.
There are several types of capacitors, and each type has two fundamental data to be identified: the voltage and the electrical capacitance.
The voltage, or rather the electric potential difference, is measured in Volt with the symbol V; it indicates the maximum value the capacitor can bear.
The electrical capacitance, instead, is indicated with the letter C, and its value is the ratio between the charge Q and the potential V. In the system of units it is the ratio Coulomb/Volt called Farad with symbol F.
Its name is due to the physicist Michael Faraday, and one Farad is an huge measure compared to the capacity of a standard capacitor, that’s why we use submultiples: microfarad “µF” or the picofarad “pF”.
The farad is directly proportional to the area of the conductive foils, inversely proportional to the distance between them, and depend on the type of dielectric insulating material.
One of the most common and simple capacitors is the ceramic capacitor.
It is disc-shaped and its dimensions are under 1 cm; it’s made with the two metal conductive foils, separated by a foil of dielectric insulating material.
They can accumulate very low charge.
The electrolytic capacitor is made of several foils wrapped with one another. It is cylinder-shaped and if we unroll it, we can see all the layers:
- there is a sheet of insulating paper between each layer;
- a positive side, it’s an aluminium foil with an oxide layer as dielectric insulator;
- a piece of paper soaked in electrolyte to better conduct electricity;
- and another aluminium foil, the negative side, that holds the charge.
The surface is way bigger than on the ceramic ones, as a matter of fact they can accumulate much more charge.
The electrolytic capacitor is polarised, which means it works only in one direction, and on the external surface the negative connector is indicated being the shorter one. If we’d invert the polarity, this would cause the overheating and consequently the explosion of the capacitor.
The next one is the tantalum capacitor.
It hasn’t a standard shape and is made mostly of sintered tantalum spheres, which means they are joined among each other to have as much surface area as possible to increase the capacity.
To this volume of tantalum, that is the positive pole, several coatings are added like:
- tantalum pentoxide as dielectric;
- than manganese dioxide, that is an electrolyte;
- a layer of graphite;
- and, eventually, a layer of silver to provide a good connection to the negative pole.
Last but not least the supercapacitor, that can accumulate a big amount of electric charge compared to traditional capacitors. As a matter of fact the values can get to the Farad.
It is usually cylinder-shaped, made of two electrodes coated of activated carbon with high surface area, a separator and an electrolyte normally liquid; all these parts are wound on themselves like an electrolytic capacitor.
Differently from electrolytic capacitors, in supercapacitors the electrolyte forms a conductive connection between the two electrodes without the dielectric insulating layer.
When electric current flows through the two polarised electrodes, they build between the electrolyte and the electrode a layer of ions with reverse polarity compared to the one of electrode.
Thanks to porosity of activated carbons, the contact surface is extended and the distance is small, because the charge separation between solid and liquid is at a molecular distance. This explains the big charging capacity.
Will supercapacitors be a “green” solution to power electronic devices in the future, thanks to their quick charge and great amount of energy they can store? Share your ideas in the comments.
If you want to learn more about diodes, transformers, electric motors and everything concerning the world of electronics, watch the videos in our playlist “Electrical Engineering”.
If you find this video interesting, let us know leaving a like and a comment below. You can also share it and don’t forget to subscribe.
It is disc-shaped and its dimensions are under 1 cm; it’s made with the two metal conductive foils, separated by a foil of dielectric insulating material.
They can accumulate very low charge.
The electrolytic capacitor is made of several foils wrapped with one another. It is cylinder-shaped and if we unroll it, we can see all the layers:
- there is a sheet of insulating paper between each layer;
- a positive side, it’s an aluminium foil with an oxide layer as dielectric insulator;
- a piece of paper soaked in electrolyte to better conduct electricity;
- and another aluminium foil, the negative side, that holds the charge.
The surface is way bigger than on the ceramic ones, as a matter of fact they can accumulate much more charge.
The electrolytic capacitor is polarised, which means it works only in one direction, and on the external surface the negative connector is indicated being the shorter one. If we’d invert the polarity, this would cause the overheating and consequently the explosion of the capacitor.
The next one is the tantalum capacitor.
It hasn’t a standard shape and is made mostly of sintered tantalum spheres, which means they are joined among each other to have as much surface area as possible to increase the capacity.
To this volume of tantalum, that is the positive pole, several coatings are added like:
- tantalum pentoxide as dielectric;
- than manganese dioxide, that is an electrolyte;
- a layer of graphite;
- and, eventually, a layer of silver to provide a good connection to the negative pole.
Last but not least the supercapacitor, that can accumulate a big amount of electric charge compared to traditional capacitors. As a matter of fact the values can get to the Farad.
It is usually cylinder-shaped, made of two electrodes coated of activated carbon with high surface area, a separator and an electrolyte normally liquid; all these parts are wound on themselves like an electrolytic capacitor.
Differently from electrolytic capacitors, in supercapacitors the electrolyte forms a conductive connection between the two electrodes without the dielectric insulating layer.
When electric current flows through the two polarised electrodes, they build between the electrolyte and the electrode a layer of ions with reverse polarity compared to the one of electrode.
Thanks to porosity of activated carbons, the contact surface is extended and the distance is small, because the charge separation between solid and liquid is at a molecular distance. This explains the big charging capacity.
Will supercapacitors be a “green” solution to power electronic devices in the future, thanks to their quick charge and great amount of energy they can store? Share your ideas in the comments.
If you want to learn more about diodes, transformers, electric motors and everything concerning the world of electronics, watch the videos in our playlist “Electrical Engineering”.
If you find this video interesting, let us know leaving a like and a comment below. You can also share it and don’t forget to subscribe.