Light up the bulb without connecting it to battery – The secret of electromagnetic induction

Have you ever wondered if it’s possible to light up a bulb without directly connecting it to a battery? The answer lies in the fascinating concept of electromagnetic induction—a principle discovered by Michael Faraday in the early 19th century.

What is an electromagnetic induction?

Electromagnetic induction occurs when a changing magnetic field creates an electric current in a conductor. The principle of electromagnetic induction is known as Faraday’s Law of Electromagnetic Induction which states that:

An electric current is induced in a coil when the magnetic flux through it changes over time.

This principle is the foundation of many modern electrical applications, which include transformers, generators, motors and wireless power transfer.

Lighting up a bulb without direct contact with battery

Now we will see how can a light up a small bulb using the concept of electromagnetic induction.

We will be requiring the following items:

1. Plastic box
2. Terminals
3. Primary Coil
4. Secondary Coil
5. LED Light Bulb
6. Resistor
7. Transistor
8. Batteries along with holder

Assemble the whole circuit as the diagram shown below.

The whole configuration will look like the one shown below figure:

Primary Coil

Secondary Coil

How it works?

What happens is when battery switch is in on position, the electric current (DC) starts to flow through primary coil. The transistor in the above circuit acts as a rapid acting switch which means that it turn on and off the primary coil many times in one second. Consequently, a changing magnetic field is produced in the primary coil due to the changing electric field as a result of transistor fast switching action.

The changing magnetic field in turn induces an electric current in the secondary coil. Since the secondary coil is connected to the LED light bulb, hence LED bulb is lit up without any physical connection to the battery.      

Electromagnetic induction is a powerful concept that enables electricity generation and wireless power transfer. By understanding this principle, we can explore innovative ways to power devices without the need for direct electrical connections. Next time, you charge your phone wirelessly or see a transformer in action, remember—you’re witnessing the magic of electromagnetic induction!

Watch the video by clicking the link below for understanding about Electromagnetic Induction: