Electrical Resistance and Ohm’s Law Electric circuits are used to convert electrical energy into some other form of energy we need. The devices we use to convert the electrical energy are called electrical loads. As the electrons flow through the circuit, they transfer energy to the material in the electrical load. The ability of an electrical load to impede the flow of electrons is called electrical resistance, and the loss of electric potential (voltage) across the electrical load is called potential difference (voltage drop). The symbol for resistance is ‘d ohm R=‘d The relationship between the potential difference across a conductor and the electric current flowing through it is called Ohm’s law. A short circuit occurs when the positive and negative terminal of a source of electrical energy are connected together by a good conductions with very low resistance. This can cause a very large current to flow from the source and may generate so much heat that fires can occur. Short circuits can occur in many different ways.