Tema 16 - Aplicações do Fenômeno da Indução | Experimento - Transformador derretendo prego

Summary

This video demonstrates how a transformer works using a simple setup with a wooden base, iron nails, and copper coils. The primary circuit consists of a coil with 300 turns connected to an alternating current, creating a varying magnetic field. This field induces an electric current in a secondary coil with only six turns. The induced current encounters resistance, especially at the iron nail, causing it to heat up and eventually reach a high enough temperature to melt, mimicking the process in an electric welding machine. The video provides a hands-on example of electromagnetic induction and heating.

Takeaways

• 😀 A simple transformer demonstration uses basic materials: wood, iron nails, copper wire coils, and iron cores.
• 😀 The primary circuit consists of a coil with 300 turns where AC current flows from the electrical grid.
• 😀 The secondary circuit features a coil with only six thick copper turns.
• 😀 The circuit is connected to an iron nail in the secondary coil to observe the effects.
• 😀 When the circuit is powered on, the primary coil generates a varying magnetic field.
• 😀 This varying magnetic field induces an electric current in the secondary coil due to the changing magnetic flux.
• 😀 The induced current in the secondary coil encounters resistance, especially at the iron nail.
• 😀 As the nail heats up, its resistance increases, causing it to become incandescent.
• 😀 The nail eventually breaks due to the increased resistance from heating.
• 😀 By re-establishing electrical contact, the nail can be welded, similar to an electric welding machine.

Q & A

What is the main purpose of the experiment described in the script?

The main purpose of the experiment is to demonstrate how a transformer works using basic materials like wood, iron nails, copper wire, and iron cores.

What materials are used to build the primary and secondary coils of the transformer?

The primary coil is made with 300 copper wire turns, and the secondary coil is made with 6 thick copper turns.

How is the current in the primary coil generated?

The current in the primary coil is generated by connecting it to an alternating current (AC) power supply.

What happens to the magnetic field when the current flows through the primary coil?

The current passing through the primary coil generates a variable magnetic field that concentrates in the iron cores.

How does the secondary coil generate an electric current?

The varying magnetic flux passing through the secondary coil induces an electric field, which causes a current to flow through it.

Why does the current in the secondary coil face higher resistance?

The current in the secondary coil encounters greater resistance due to the presence of an iron nail, which begins to heat up.

What effect does the heat have on the iron nail?

As the iron nail heats up, its resistance increases, and it eventually reaches a point where it becomes incandescent and may break.

What is the significance of the iron nail in the secondary coil circuit?

The iron nail serves as the point of increased resistance, causing it to heat up and demonstrate the heating effect of electrical resistance.

How is the iron nail repaired during the experiment?

Once the nail breaks, it can be electrically reconnected by establishing contact between the separated parts, similar to the process in an electric welding machine.

What is the role of the iron cores in the transformer experiment?

The iron cores help to concentrate and guide the magnetic field generated by the primary coil, enhancing the induction process in the secondary coil.