Capacitors

Posted: February 13, 2014 in Physics

A capacitor is a component that stores energy in it. It has two plates with a dielectric material in between. The greater the energy stored, the greater the capacitance. The greater the area of the capacitor plates, the greater the capacitance and the lesser the distance between the plates, the greater the capacitance. Apart from its dependence on its plate distance and area, capacitance is also dependent on the type of dielectric material it is made of.
Some examples of dielectric material are sand, glass, plastic etc.

Capacitors are widely used. Some examples include alarm clock, XRAY machines, calculators and hybrid cars etc.

Technically, capacitors store charge. They can be easily charged by a battery. This stored energy can be to put to use in many ways, for example, in lighting up a bulb. But one thing to keep in mind is that a capacitor loses its charge rather quickly, unlike a battery. So, a bulb would go off or become dim once the capacitor has been completely discharged. And this would happen rather quickly.

Once a capacitor has fully charged, a DC current cannot flow through it. However, an alternating current can always flow through it.

Mathematically, capacitance is found by the formula C=Q/V where Q is the charge and V is the voltage.

The capacitors can be placed in series and in parallel just like the resistors. However, the calculation is opposite to that of the resistors. When capacitors are in parallel, their capacitance is just added. When in series, the inverse of each capacitor is added and the total is inversed.

Just for entertainment, here is the link to a post: http://www.instructables.com/id/Make-A-Water-Bottle-Capacitor/?ALLSTEPS. This person actually puts the extra water bottles to good use by turning them into a capacitor. This is just for entertainment purposes. Try at your own risk if you are really interested.

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