Quantitative relationship between
current, voltage and resistance
In this unit you will investigate in a quantitative way, how voltage, current and resistance relate to each other in a circuit. Voltage and current All other things being equal, an increase in voltage will produce a corresponding increase in current, or flow of electrons. Voltage and current are related in a positive way, as one increases the other increases and vice versa. The graph to the right illustrates the positive correlation between current and voltage.
Assuming that the voltage remains the same, what would happen to the current if the resistance within a circuit is increased? This is like plugging more globes into a circuit, as the resistance increases, the current decreases. In this case, there is a inverse relationship between the two variables. As the resistance increases, the current decreases, provided all other factors are kept constant. Materials with low resistance, metals for example, are called electrical conductors and allow electricity to flow easily. Those materials with high resistance, like plastics, are called electrical insulators.
Georg Ohm put these observations into an equation to allow measurement of each variable. This law is named after him and is called Ohm's Law. See the topic Ohm's law.
