Relationship between the current and voltage.

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Relationship between the current and voltage

Aim: To investigate the relationship between Current and Voltage

Scientific Knowledge

The current and voltage of an electric circuit, is given by the formula V=IR. This is known as Ohms. Ohm´s Law is only applicable, when the temperature of the resistor is kept constant. Therefore Ohms law is only applicable to Ohmic conductors. An example of Ohmic conductors are metals and alloys at constant temperatures. Anything that doesn´t obey Ohms law, are know as non-Ohmic Conductors. Examples of these are Silicon, and Germanium.

Resistance

Ohmic Conductors Non-Ohmic Conductors

Obey Ohms Law Don't obey Ohms Law

Metals & Alloys Semi-Conductors

Resistance Increases with temperature Resistance decreases with temperature

At very low temperatures it becomes Since the resistance decreases with

a Superconductor temperature, they are called thermistors

Superconductors

At very low temperatures, atoms hardly vibrate at all.

Therefore the resistance is almost 0 Ohms, and the conductors are very good.

These are Superconductors.

The resistance of a component can also be calculated, by the formula, R =KL/A.

This is where the cross sectional area is inversely proportional to the resistance,