## Capacitors, Capacitance and Dielectrics

Hi,

So I am learning about parallel-plate capacitors.

The way my book puts it is that it is basically two parallel plates of opposite polarities, separated by a distance d. In order to establish that distance, work must be done and the energy is stored as electric potential energy.

From that description, I understand that the purpose of a capacitor is to store potential energy.

I then learn that a dielectric can increase the capacitance of a capacitor by decreasing the potential difference but, in the process, it diminishes the stored potential energy, according to the equation:

Energy = Q2/C

Why, then, is a dielectric used if it decreases the potential energy (what I thought as the function of the capacitor)? The purpose of a capacitor is to store more charge? There must be a connection I am not seeing.

Can anyone elucidate me?

Thanks!
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 The value of C does not on it's own determine how much energy is stored in the capacitor. Take a look at the other ways of expressing the energy stored.. http://hyperphysics.phy-astr.gsu.edu...ic/capeng.html For example Energy = 0.5CV2 See in this one Energy is proportional to C !