|Sep7-12, 12:16 PM||#1|
Capacitors, Capacitance and Dielectrics
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?
|Sep7-12, 01:46 PM||#2|
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..
Energy = 0.5CV2
See in this one Energy is proportional to C !
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