Electrical Resistance Electrical Resistance and Ohm’s Lawand Ohm’s Law

Electric circuits are used to Electric circuits are used to convertconvert electrical energy into electrical energy into some other some other formform of energy we of energy we

needneed..

The The devicesdevices we use we use to convert the to convert the electrical electrical energyenergy are are called electrical called electrical loadsloads..

As the electrons As the electrons flowflow through the circuit, through the circuit, they they transfertransfer energy energy to the material in the to the material in the electricalelectrical load. load.

The The abilityability of an electrical load to of an electrical load to impedeimpede the flow of electrons is the flow of electrons is called electrical called electrical resistanceresistance, and the , and the loss of electric loss of electric potentialpotential (voltage) (voltage) across the electrical load is called across the electrical load is called potential potential differencedifference (voltage drop). (voltage drop).

The symbol for The symbol for resistanceresistance is ‘ is ‘ohm ohm R=‘R=‘

The relationship between the The relationship between the potentialpotential difference across a difference across a conductorconductor and the electric and the electric currentcurrent flowing through it is called Ohm’s flowing through it is called Ohm’s lawlaw..

A short circuit occurs when the A short circuit occurs when the positivepositive and negative terminal of a and negative terminal of a sourcesource of electrical energy are of electrical energy are connectedconnected together by a good together by a good conductions with very conductions with very lowlow resistance.resistance.

This can cause a very This can cause a very largelarge current current to flow from the to flow from the sourcesource and may and may generate so much generate so much heatheat that fires can that fires can occur.occur.

Short circuits can occur in many Short circuits can occur in many different ways.different ways.