Electrical Engineering ⇒ Topic : Electric Current

Electric Current

The directed flow of free electrons (or charge) is called electric current. The flow of electric current can be beautifully explained by refering to Fig.(a). The copper strip has a large number of free electrons. When electric pressure or voltage is applied, then free electrons, being negatively charged, will start moving towards the positive terminal around the circuit as shown in Fig (a).This directed flow of electrons is called electric current.

                                                                    figure (a)

The reader may note the following points :

Current is flow of electrons and electrons are the constituents of matter. Therefore, electric current is matter (i. e. free electrons) in motion.

The actual direction of current (i. e. flow of electrons) is from negative terminal to the positive terminal through that part of the circuit external to the cell. However, prior to Electron theory, it was assumed that current flowed from positive terminal to the negative terminal of the cell via the circuit. This convention is so firmly established that it is still in use. This assumed direction of current is now called conventional current