Capacitor

Capacitance of spherical capacitor with mixed dielectrics: Let us consider A and B are the two concentric spherical shells of radii a and b respectively (b >a). Shell A is charged by Q and the outer surface of shell B is earthed. Let a shell filled with dielectric medium of dielectric constant K2 of inner […]

A capacitor has rectangular plates of length a and width b. The top plate is inclined at a small angle . Find the capacitance of the capacitor. Let us consider the given capacitor is made of large number of elementary capacitors connected in parallel. Let an elementary capacitor of width dx at a distance x

Charging and discharging of a capacitor: Charging: Let us consider a capacitor C is connected to a battery of emf E through a resistance R. During charging of the capacitor the potential difference across the plates becomes equal to the emf of the battery. Let at any time t, I is the current through the

Capacitance due to variable electric field: If the two conductors A and B carry equal and opposite charges create a non-uniform electric field then find the capacitance of the system. The distance between the conductors is d. If Q is the charge of each conductor and electric field E = (a + by) varies along

Kirchhoff’s law for capacitor: (i) Junction law: It states that in any isolated system of capacitor the net charge is conserved. So, the incoming charge at any junction is equal to the outgoing charge from the junction. At point P the charge incoming is taken as positive and charge outgoing is taken as negative. So,

6. Wheatstone bride combination: Calculate equivalent capacitance between points A and B. If the ratio of capacitors C1 and C2 is same to the ratio of capacitors C3 and C4 then no charge pass through capacitor C5. So, the capacitors C1, C2 and C3, C4 are in series connection and their combinations are in parallel

1. Capacitors in series: Let us consider three capacitors C1, C2 and C3 respectively are connected in series in between points AB, BC, CD with a cell as shown in figure. The potential difference between points AB, BC, CD are respectively (VA  – VB), (VB-VC) and (VC-VD). Q is the charge flows through the circuit.

Energy stored in a capacitor: Let us consider initially the plates of a capacitor are uncharged and small positive charges are repeatedly transferred from one plate to the other plate. Let at any instant q be the total quantity of charge transferred and v be the potential difference between the plates. Then, q = Cv

Capacitance of a spherical capacitor (outer sphere is earthed): Let us consider A and B are the two concentric spherical shells of radii a and b respectively (b >a). Shell A is charged by Q and the outer surface of shell B is earthed. So –Q charge is induced in the inner surface of B.

Capacitance: If the charge of a conductor is increased then the potential of the conductor is also increased. Thus, charge (Q)  potential (V) or, Q = CV ——–(1) where C is the capacitance of the  conductor and that conductor is called capacitor. From equation (1) C = ——-(2) so, the capacitance of the  conductor is