Capacitors, Physics

Capacitors:

When a voltage is applied to a capacitive circuit there is a change in the electric flux. The ease with which this change takes place is a measure of the capacitance of the circuit.

In d.c. circuits, capacitance is only effective when the voltage is switched on and off, but in a.c. circuits where the voltage varies continuously, the effect of capacitance is continuous.

A device used specifically to introduce capacitance into a circuit is known as a capacitor (sometimes called a condenser).

CHARGING A BODY

A conductor is given a positive charge when electrons are forcibly removed from the conductor, eg, by connecting it to the positive pole of a d.c. source. Similarly, when additional electrons are pushed on to a conductor, it is given a negative charge.

The use of force means that energy has been expended by the source of d.c. and this energy is stored in an electric field. An electric field is represented by lines of flux whose direction is the direction of force which would be experienced by a free positive charge placed in the field. Lines of electric flux behave in an analogous manner to lines of magnetic flux.

As the charge on a body increases, it repels further charge with greater force until eventually the repelling force equals the charging force and the conductor is fully charged.

The charge on a fully charged body may be changed by changing the voltage supplying the charging force, but the conductor will oppose this charge due to the charge it already possesses.

Any conductor will hold a charge, the magnitude of the charge depends upon the magnitude of the voltage applied, but for a single conductor, even a large voltage produces only a relatively small charge

Posted Date: 9/13/2012 4:12:23 AM | Location : United States







Related Discussions:- Capacitors, Assignment Help, Ask Question on Capacitors, Get Answer, Expert's Help, Capacitors Discussions

Write discussion on Capacitors
Your posts are moderated
Related Questions
The photon fluence rate is 10 7 photons mm -2 sec -1 for a beam of γ rays. One fourth of the photons have energies of 100 keV, one half have energies of 80 keV and the remaining

An open barge has the dimensions 22x40x12m. If the bargeis made out of 4.0-cm-thick steel plate on each of its four sides and its bottom, what mass of coal can the barge carry in f

What do you mean by normal adjustment of a telescope? In What way it is better? What is the need of erecting lens in a terrestrial telescope? What do you mean by its magnific

Write down the condition for the construction of good auditoria. Illustrate the reflection of waves at closed and open ends.

define composition of s.h.m. lijassious figures

As regards cases involving the application of the Biot-Savart Law to calculate the magnetic field due to an electric current which of the following statements about why it is relat

What is the difference between vibration and waves?

Places where friction occurs Locate the places on several mechanical devices where parts rub together. Roller skates, pulleys and the wheels of toys often required oil. Try to

why metallic frame used in searles apparatus

1.Consider the dangers of using a camp stove inside an enclosed space like a tent. Test data show that a high heat liquid fuel camp stove can dramatically increase CO mixing ratios