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Resources | Electronics for young innovators Electrical Current All materials are made up from atoms, and all atoms consist of protons, neutrons and electrons. Protons, have a positive electrical charge. Neutrons have no electrical charge while Electrons, have a negative electrical charge. Atoms are bound together by powerful forces of attraction existing between the atoms nucleus and the electrons in its outer shell. Electrons are attracted towards the nucleus (protons + neutrons). When isolated from the nucleus the electrons exert a potential of attraction called potential difference. When there is closed circuits [i.e; there is a wire a between its positive and negative node], the free electrons start moving and drifting back to the protons due to their attraction, thus creating a flow of electrons. This flow of electron is called Electrical current. Electrons do not flow freely through the circuit as the material they move through creates a restriction to the electron flow. This restriction is called resistance.
Symbol for
Resistance s Re
nc ista e
The Resistance, ( R ) of a circuit is its ability to resist or prevent the flow of current (electron flow) through itself making it necessary to apply a greater voltage to the electrical circuit to cause the current to flow again. Resistance is measured in Ohms, Greek symbol ( Ω, Omega ) with prefixes used to denote Kilo-ohms ( kΩ = 103Ω ) and Mega-ohms ( MΩ = 106Ω ). [ Note : Resistance cannot be negative in value only positive.] designed & conducted by Soujanyaa and Priya, Chlorophile © 2014