GCSE Physics - How Transformers Work #82

Summary

This video explains the function of transformers in the UK's national grid, highlighting their role in voltage management. Electricity generated at power stations is stepped up to 400,000 volts for efficient transmission across the country, reducing energy losses. Upon reaching its destination, the voltage is stepped down to a safe 230 volts for household use. The video breaks down the operation of transformers, detailing how alternating current generates magnetic fields, induces voltage in coils, and facilitates energy transfer while adjusting voltage levels to meet transmission and usage requirements.

Takeaways

• ⚡ Transformers are essential in the UK national grid, converting voltage for efficient electricity transmission.
• 🔋 Electricity generated at large power stations is stepped up to approximately 400,000 volts using step-up transformers.
• 🌍 High voltage minimizes energy losses as electricity travels across long distances through wires and pylons.
• 🏠 Upon reaching local areas, step-down transformers reduce voltage to a safe level of about 230 volts for household use.
• 🧲 A transformer consists of two coils (primary and secondary) and an iron core that facilitates energy transfer through magnetic induction.
• 🔄 An alternating potential difference in the primary coil creates an alternating magnetic field.
• 🌌 The iron core, being a magnetic material, enhances the magnetic field, allowing it to induce a potential difference in the secondary coil.
• 🔗 The flow of electricity in the secondary coil occurs only when the circuit is complete.
• ⬆️ Step-up transformers increase voltage by having more turns in the secondary coil compared to the primary coil.
• ⬇️ Step-down transformers reduce voltage when the secondary coil has fewer turns than the primary coil.

Q & A

What is the primary function of a transformer in the national grid?

The primary function of a transformer in the national grid is to increase or decrease the voltage of electricity for efficient transmission and safe usage.

Why is electricity stepped up to around 400,000 volts in the national grid?

Electricity is stepped up to around 400,000 volts to minimize energy losses as it is transmitted over long distances through wires and pylons.

What happens to the voltage when electricity reaches smaller towns?

When electricity reaches smaller towns, it passes through a step-down transformer, which decreases the voltage to around 230 volts for safe use in homes.

What are the main components of a transformer?

The main components of a transformer include the iron core, primary coil, and secondary coil.

How does an alternating potential difference affect the primary coil?

An alternating potential difference applied across the primary coil causes a current to flow, generating an alternating magnetic field around the coil.

What role does the iron core play in a transformer?

The iron core connects the primary and secondary coils and helps to induce a magnetic field, allowing the transfer of energy between the coils.

How is a potential difference induced across the secondary coil?

The alternating magnetic field in the iron core induces a potential difference across the secondary coil, which causes current to flow if there is a complete circuit.

Why can't electricity pass directly between the primary and secondary coils?

Electricity cannot pass directly between the primary and secondary coils because the wires are insulated in plastic, preventing direct conduction.

What distinguishes a step-up transformer from a step-down transformer?

A step-up transformer has more turns in the secondary coil than in the primary coil, resulting in increased voltage, while a step-down transformer has fewer turns in the secondary coil, reducing the voltage.

What is an example of voltage change in a step-up transformer?

In a step-up transformer, if a 10-volt supply is input, it can produce a 20-volt supply output due to having twice as many turns in the secondary coil compared to the primary coil.