SAMPLE PROBLEM 16B A conductor holds 15 C of charge when it has a potential of 12 V. What is its capacitance?
SAMPLE ANSWER 16B The conductor has a capacitance of 1.25 F.
Capacitor
CAPACITOR A capacitor is an electrical device capable of storing electric charge.
The circuit symbol for a capacitor is Parallel Plate Capacitor
A parallel plate capacitor is a pair of metal plates separated by a thin sheet of insulated material called the dielectric. The dielectric may be air, mica, ceramic, tantalum, aluminium oxide, etc.
Factors affecting the capacitance of a parallel plate capacitor
When the capacitor is charged, the plates carry equal amounts of charge but of opposite sign. The capacitance of a parallel plate capacitor is directly proportional to the common area shared by the plates and the permittivity of the medium between them, and inversely proportional to the distance between them.
By defining the units as we do, we get k 1 and thus: C r eA
d QC k eA d Capacitors on a DVD circuit
C Q V QC 15 106
12 1.25 106
CAPACITANCE OF A PARALLEL PLATE CAPACITOR
C eA d
C capacitance, permittivity, A Common Area, d distance between plates e
