Build Faraday Flashlight: Will Generator Work?

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In summary, the conversation is about building a Faraday flashlight and using a cylindrical Neodymium magnet inside a plastic tube to generate power. The individual asks if connecting a CRO and adding 4 Schottky diodes would increase the voltage output. The response mentions that rectifying the pulses would allow for charging a capacitor, but also notes that some voltage may be lost due to the diodes' minimum voltage requirement. The use of Schottky diodes is recommended for their lower threshold voltage. The conversation also discusses the potential for the Neodymium magnet to chip easily and suggests using soft foam to protect it from impact.
  • #1
JoonasN
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Homework Statement


I am trying to build a faraday flashlight and I need to know if this generator would work.

Homework Equations



I added a rough diagram to help illustrate this...3.
The attempt at a solution

I have a DIA20 x L10 cylindrical Neodymium magnet moving up and down inside a plastic tube 30mm long. Both ends of the tube are closed. The ID of the plastic tube let's the magnet move along the tube smoothly. Enameled copper wire is wound around the outside of the tube to form a 10mm long solenoid at the center of the tube, about 16 turns are used. Both ends of the wire are connected to a CRO. Will the CRO record any output? If yes, then would adding 4 Schottky diodes double the voltage?

Thanks,
Joonas
 

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  • #2
You would get a positive going pulse as one pole entered the coil and a negative going pulse as the other end entered the coil. And you would also get pulses as the magnet came out of the coil.

Rectifying this series of pulses would let you charge up a capacitor, because the rectified pulses would all have the same polarity, but all diodes have to have a minimum voltage before they will conduct. So you can lose some of your voltage like that.
As you suggest, Schottky diodes are better at this than most other types as they have a lower threshold voltage.

Neodymium magnets are very brittle and will chip easily if they are allowed to hit anything, so you need to be aware of this. Some of them are nickel plated and these seem more resistant to chipping, but they still chip if you hit them against anything.
Maybe you could put soft foam or something like that at the ends of the tube, to absorb some of the shock.

Welcome to the Forum. Questions like this can go in the Electrical Engineering section if you like as it isn't homework related.
 
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  • #3


Based on your description, it seems like the setup you have created could potentially generate some electricity. However, there are several factors that could affect the efficiency and effectiveness of your faraday flashlight. First, the strength and movement of the magnet will play a significant role in the amount of electricity generated. Additionally, the number of turns in the solenoid and the gauge of the wire used can also impact the output.

In terms of the CRO recording any output, it is possible but it may be a small amount. The addition of Schottky diodes may increase the voltage, but it would also depend on the specific diodes used and the overall setup of the circuit.

Overall, while your setup may generate some electricity, it may not be enough to power a flashlight. I would recommend further experimentation and tweaking of your setup to optimize its efficiency. Additionally, researching and incorporating other components, such as a capacitor, may also improve the output.
 

Related to Build Faraday Flashlight: Will Generator Work?

1. Can I use any type of generator for the Faraday flashlight?

Yes, as long as the generator produces a direct current (DC) output and is small enough to fit inside the flashlight's casing.

2. How long will the flashlight stay lit with one crank of the generator?

The duration of light will depend on the efficiency of the generator and the strength of the cranking motion. Generally, one crank can generate enough power for several minutes of light.

3. Do I need any special tools or materials to build the Faraday flashlight?

No, the flashlight can be built with basic household items such as a cardboard tube, copper wire, and a magnet. However, having a soldering iron or electrical tape can make the construction process easier and more secure.

4. How do I know if the generator is working properly?

You can test the generator by connecting it to a volt meter and cranking the handle. The meter should show a reading of at least 1.5 volts to power the LED light.

5. Is the Faraday flashlight waterproof?

The basic design of the Faraday flashlight is not waterproof. However, you can make it waterproof by using a water-resistant casing or by coating the inside components with a waterproof sealant.

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