Electricity powers the modern world. It is essential for electronic devices, home appliances, travel and school, work and leisure.
The widespread use of electricity is because we can make so many components that have different electrical behaviours, and then combine them to make all sorts of devices and machines. These behaviours can be seen most easily by creating a graph of the electrical current (I) through a component against the potential difference (V) placed across it. This graph is known as a component’s IV characteristic.
The simplest component is the electrical resistor. These have fixed electrical resistance, which means the electrical current is proportional to the potential difference and the IV characteristic is linear. Resistors are vital to almost all electrical devices, from a mobile phone to the world’s most powerful supercomputer, a flashlight to electric vehicles, an electric toothbrush to a medical scanner, your internet router to a communications satellite, or a vacuum cleaner to air-conditioning.
Diodes are made of two different semiconductor materials joined together and only allow electricity to flow in one direcion through them. They are hugely important in electronics and electrical engineering. They are most often used to convert alternating current (AC) electricity to direct current (DC), for example to convert mains electricity into 12 V DC used for charging mobile devices. They are also widely used to protect electronic circuits by preventing unwanted currents.
Filament lamps might not be used for lighting as much as they once were but they show interesting electrical effects. They contain a long, thin metal 'filament' that heats up when high electrical current is flowing, which results in it starting to glow and give off light. The heating also changes the filament's electrical resistance, which results in a non-linear IV characteristic.
This virtual experiment will allow you to explore the electrical behaviour of resistors, diodes and filament lamps. You can take measurements of current and potential difference, plot a graph of their IV characteristics, and find their resistance values.