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- PHY102 Physics II © Dr.Cem Özdoğan
- A parallel-plate capacitor, made up of two plates of area A separated by a distance d. The charges on the facing plate surfaces have the same magnitude q but opposite signs
- As the field lines show, the electric field due to the charged plates is uniform in the central region between the plates. The field is not uniform at the edges of the plates, as indicated by the “fringing” of the field lines there.
- The charge q and the potential difference V for a capacitor are proportional to each other:
- When a capacitor is charged, its plates have charges of equal magnitudes but opposite signs: q+ and q-.
- However, we refer to the charge of a capacitor as being q, the absolute value of these charges on the plates.
- The proportionality constant C is called the capacitance of the capacitor.
- Its value depends ONLY on the geometry of the plates
- not on their charge or potential difference.
- The SI unit is called the farad (F): 1 farad (1 F)= 1 coulomb per volt =1 C/V.