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The electrical resistivity of a wire tells us how well the wire material conducts electricity. This is crucial information for any application that involves conducting electricity, including wind turbines, electric vehicles, household electrical goods and computers. Here you can measure the resistivity of wires of different materials and widths, and consider which would be best suited for conducting electricity.
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Electronic materials are crucial to our life today, and electrical ‘resistivity’ tells us how good or poor a material is at conducting electricity.
We use materials with low electrical resistivity to transmit electrical power from generators, across grid distribution networks, and to homes and workplaces for use. Designers of electrical devices rely on knowing the resistivity of wire used in order to calculate the resistance of components.
These devices range in size from enormous machines such as wind turbines or industrial lifting equipment; motors or engines in electric vehicles and all-new electric aircraft; consumer products such as washing machines, hair dryers and ovens; and the nanoscale components within the computer chips found in smart devices, laptops, and mobile phones.
In fact, modern computing is based on controlling the resistivity of semiconductor materials in a type of transistor (known as ‘field effect transistors’ using ‘CMOS’ technology).
Measuring electrical resistivity helps us to understand the properties of materials, to monitor manufacturing processes, and to select the best material for an application.
Click on the link below to download the Quick Guide for using the Resistivity experiment. Or follow the brief instructions here:
Click on the link to download a pdf of the Instructions for operating the Resistivity experiment
Click on the link below to download a pdf of example questions for the Resistivity experiment.
Click on the link to download the Background pdf for the Resistivity experiment.
An 'IV characteristic' of a device shows how the electrical current in the device changes with applied potential difference. The IV characteristic is linear for some devices and nonlinear for others. This experiment allows you to explore the IV characteristics of resistors, a filament lamp and diodes by changing and measuring potential difference and current.
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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.
Download the file from the link below to see the Quick Guide to use the IV Characteristics of Devices experiment (requires log in)
Download the file from the link below to see the full Instructions for the IV Characteristics of Devices experiment (requires log in)
The activity sheets can be downloaded using the link below (requires log in). This contains details of the following:
Download the file from the link below to see the scientific Background to the IV Characteristics of Devices experiment (requires log in)
Understanding the electric resistance of metal wires is fundamental to being able to design electrical machines and electronic devices. In this experiment, you can vary the effective length of a wire by moving an electrical contact and then go on to measure the wire's electric resistance by measuring potential difference and electric current on analogue dials.
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Electricity powers so much of our life today. We use metal wires to transmit electrical power from power generators, such as power stations, ‘PV’ (photovoltaic) devices and wind turbines, to our homes and workplaces.
We use ‘resistance’ to measure how easily materials allow electrical current to flow. It is vital to the design of power distribution networks over long distances to understand how the length of a metal wire affects its resistance.
On smaller scales, it is important to know how the length of a conducting wire changes its resistance for applications that use motors, from washing machines through to electric cars and industrial machines. Electricity is also used in heaters, from industrial furnaces for large-scale materials processing through to ovens, underfloor heating and kettles, and in all sorts of electronic devices, such as computers, screens and sensors.
Designing any of these applications to be efficient and effective requires understanding how electricity flows through the materials in the various devices. This FlashyScience gives an excellent introduction to this subject that is vital to our living today.
Click below to download the Quick Guide for the Resistance experiment (requires login)
Click below to download a pdf of the full instructions to use the Resistance experiment (requires login)
Click below to download activity sheets and worksheets for investigating:
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Click below to download a pdf of the background theory (requires login)
