Electrical Engineering ⇒ Topic : Potential Difference

Potential Difference

The unit of potential difference is volt. Its symbol is V. One volt is defined as the difference of potential between two points of a conducting wire carrying a current of 1 ampere, when the power dissipated between these points is equal to 1W.

Potential Difference

The difference in the potentials of two charged bodies is called potential difference.If two bodies have different electric potentials, a potential difference exists between the bodies.Consider two bodies A and B having potentials of 5 volts and 3 volts respectively as shown in Fig.  (a). Each coulomb of charge on body A has an energy of 5 joules while each coulomb of charge on body B has an energy of 3 joules. Clearly, body A is at higher potential than the body B.

                                              (a)

                                                (b)

If the two bodies are joined through a conductor [See Fig. (b)], then electrons will *flow from body B to body A. When the two bodies attain the same potential, the flow of current stops.

Therefore, we arrive at a very important conclusion that current will flow in a circuit if potential difference exists. No potential difference, no current flow. It may be noted that potential difference is sometimes called voltage.

Unit. Since the unit of electric potential is volt, one can expect that unit of potential difference will also be volt. It is defined as under

The potential difference between two points is 1 volt if one joule of work is **done or released in transferring 1 coulomb of charge from one point to the other