The electrical resistance of a conductor is a measure of its opposition to the flow of the electric current.

In this teaching unit you will learn: To understand the parallelism between an electric circuit and the distribution of water in a closed circuit. To learn the characteristic magnitudes which describe an electric circuit: the potential difference, intensity, resistance, electromotive and counter electromotive force. To demonstrate and understand the fundamental laws which relate these magnitudes. To be able to calculate intensities, tension, power and energy in simple circuits.