# DIY Electromagnetic Induction Experiment

• KDPhysics
In summary, the conversation discusses a video demonstrating DIY experiments on electromagnetic induction. The video shows how to create a transformer without using an iron core by running 30-50 kHz AC through a primary coil and inducing a current in a secondary coil attached to a light bulb. The light bulb does not turn off and on as expected, possibly due to the high frequency of the AC and the persistence of vision. The video also features an LED that blinks at 30 kHz, but cannot be seen due to the image persistence on the retina.
KDPhysics
So I was watching this video containing DIY experiments on electromagnetic induction .
At minute 4:45, the dude pretty much creates a transformer without using an iron core.
He runs 30-50 kHz AC in a coil (forming the primary circuit) and then brings another coil with its ends attached to a light bulb (forming the secondary circuit).
As the current runs into the primary circuit, a magnetic field is created as shown below. Since this is AC, the magnetic field changes polarity 30-50 thousand times every second. This in turn induces a current in the secondary coil, which by Faraday's Law must be a current running in the same direction as the primary circuit.
In the video, we can see that the light bulb lights up, but doesn't turn off and on as it should.
Could this be because of the extremely high frequency of AC, which makes the light bulb turn on and off 30-50 thousand times a second?
Or is the current induced in the secondary coil actually direct current?

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KDPhysics said:
Could this be because of the extremely high frequency of AC, which makes the light bulb turn on and off 30-50 thousand times a second?
It's more because the light bulb can't heat and cool fast enough for the brightness to change in one cycle. But even if it could do that (e.g. a neon lamp or fluorescent lamp), your eyes still can't track the brightness variations anyway (persistence of vision). This applies even at typical mains frequencies like a mere 50 or 60 cycles per second.

anorlunda, vanhees71 and KDPhysics
In the secondary coil he has a LED (a light emitting diode). The LED blinks at 30 KHz but the video is made at 50 Hz. The image persistence on the retina is 30 ms thus you can not see that the LED blinks in the video (not if you make the experiment)

## 1. How does electromagnetic induction work?

Electromagnetic induction is the process of creating a current in a conductor by varying the magnetic field around it. This can be achieved by either moving the conductor through a stationary magnetic field, or by changing the magnetic field around a stationary conductor. The changing magnetic field induces a current in the conductor, according to Faraday's law of induction.

## 2. What materials do I need for a DIY electromagnetic induction experiment?

To perform a simple electromagnetic induction experiment, you will need a coil of wire, a magnet, a battery, and a light bulb. You may also need a switch or other components depending on the specific experiment you want to conduct.

## 3. How can I make a simple generator using electromagnetic induction?

To make a simple generator using electromagnetic induction, you will need a coil of wire, a magnet, a shaft, and a way to rotate the shaft (such as a hand crank). As the shaft is rotated, the magnet will move in and out of the coil, creating a changing magnetic field and inducing a current in the coil. This current can then be used to power a light bulb or other device.

## 4. Can I use different types of magnets for an electromagnetic induction experiment?

Yes, you can use different types of magnets for an electromagnetic induction experiment. The strength and type of magnet will affect the strength of the induced current, so you may need to adjust other components (such as the number of coils) accordingly.

## 5. Are there any safety precautions I should take when conducting an electromagnetic induction experiment?

Yes, there are a few safety precautions to keep in mind when conducting an electromagnetic induction experiment. Make sure to use insulated wire and avoid touching the wire while the experiment is in progress. Also, be careful when handling magnets, as they can be strong and may pinch or attract metal objects. Lastly, always use caution when working with electricity and follow proper safety protocols.

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