Mystery of Capacitance Increase with Dielectric Insertion

[cragar]

I thought capacitance was a function of geometry. So how come when we put in a dielectric in between a parallel plate capacitor it increases the capacitance. Is this because we can increase the E field in between without worrying about dielectric breakdown. Or does it have something to do with induced surface charges on the dielectric.

 

[DragonPetter]

I thought capacitance was a function of geometry. So how come when we put in a dielectric in between a parallel plate capacitor it increases the capacitance. Is this because we can increase the E field in between without worrying about dielectric breakdown. Or does it have something to do with induced surface charges on the dielectric.

Capacitance is a function of geometry and also the permittivity of the medium. The dielectric changes the permittivity. A dielectric material's molecules individual electric charge will alter the strength of the electric field between the plates. This means you can push more electrons between the plates for the same voltage if you change the dielectric, because the electric field won't be as strong. You can think of the dielectric as where the actual energy is stored.

 

[cragar]

ok , thanks for your answer.