The electrical resistance of an electrical conductor is a measure of the difficulty of passing an electric current through that conductor. It explains the relationship between voltage (amount of electrical pressure) and the current (flow of electricity). With more resistance in a circuit, less electricity will flow through the circuit.
Resistance, discovered by Georg Simon Ohm in 1827, is the ratio between voltage and current. Ohm's law said that the voltage between any two points in a conductor changes directly as the current between the two points, given the temperature remains the same. He described it with the equation:
R = V / I which models the ratio, where: R is the resistance of the object, measured in ohms (Ω), V is the voltage across the object, measured in volts (V) and I is the current going through the object, measured in amperes (A).