How does an LED light work.?

Question

Can I make one as a science project with my son?

Answer 1

LED is an abbreviation for Light Emitting Diode. It is a semiconductor junction which, when the voltage goes over the "diode threshold" of about 0.6 volts, it emits light.

To make one, you would need pretty exotic materials from a semiconductor or materials-science lab.

Hooking one up is really simple.

Its a diode, so whether you hook up positive or negative matters.
You can just guess and reverse the leads if it dosen't light up.
You need a current-limiting resistor in series with the LED. You might opt for a potentiometer (variable resistor;rheostat) That way you can dim the led

one end of the led goes to battery (2x1.5V in series=3V), 6V or 9V
other end of led goes to potentiometer end lead. potentiometer wiper lead goes back to battery. If it dosen't work, reverse the led leads or the battery leads. A 1K potentiometer would probably be a good choice.
go to radio shack and the guy will help you pick out everything. $10

You can substitute different value resistors in about the 100 to 1K range for the potentiometer (pot) If you use the pot, one lead will be unconnected. Don't worry about it.

A really cool project uses a 7400 NAND chip on a breadboard.
Wired as a flip-flop, the chip remembers the state on or off and can control a red and a green led. It sounds kind of lame, but is the core project for understanding logic chips, memory and interfacing. Even though touching the switch just toggles green or red, it debounces the switch, so the smoothness is noticable.
It looks like it was switched by a computer, and in fact it is (a really really primitive computer building block)

this would make a great signal for a model train!

look on the net for wiring a 7400 as a flip-flop and go from there. Or try model train signal and that may turn up a plan.
This might be a better project for later on.
I mention it, because it seems super-lame, but is actually pretty cool. And you have the satisfaction of having used a logic chip.

Answer 2

No, you can not make one yourself. This is because to genuinely make one, you will have to have a pure silicone and you have to add just the right amount of inpurity to make P and N type, then fuse them together. This is way beyond the ability of any home labs.

LED (Light Emitting Diodes) are simply two types of semi-conductors touching each other. When current is applied, the free electrons get excited and in term emit light.

What you CAN do is, you could take a large silicon transistor encased in metal can (called TO-3 type - available from surplus stores), then file off the top using hacksaw. Then apply a small amount of current between the can and one of the leads in the right direction. (use 250 ohm resister with 9v battery in series so it won't supply too much current) Voila! It glows!

All you did is using half of the transistor but you can actually see how the transistor is constructed, and it is very similar to the construction of the LEDs.

Besides, I thought it was fun many years ago.

This is probably as close as you can get in creating LEDs.

Answer 3

ight emitting diodes, commonly called LEDs, are real unsung heroes in the electronics world. They do dozens of different jobs and are found in all kinds of devices. Among other things, they form the numbers on digital clocks, transmit information from remote controls, light up watches and tell you when your appliances are turned on. Collected together, they can form images on a jumbo television screen or illuminate a traffic light.
Basically, LEDs are just tiny light bulbs that fit easily into an electrical circuit. But unlike ordinary incandescent bulbs, they don't have a filament that will burn out, and they don't get especially hot. They are illuminated solely by the movement of electrons in a semiconductor material, and they last just as long as a standard transistor.

Answer 4

Does LED lights provide off UV? If not maximum reptiles will choose UV lights so are you going to provide it or in basic terms use the LED lights which will be bypass for lights up a cage, yet what about warmth? Will the LEds provide off adequate to warmth up the tank to the ranges necessary? If the answer isn't any, then you definitely will favor to stay faraway from LEDs. only a theory.

Answer 5

LEDs create light by electroluminescence in a semiconductor material. Electroluminescence is the phenomenon of a material emitting light when electric current or an electric field is passed through it - this happens when electrons are sent through the material and fill electron holes. An electron hole exists where an atom lacks electrons (negatively charged) and therefore has a positive charge. Semiconductor materials like germanium or silicon can be "doped" to create and control the number of electron holes. Doping is the adding of other elements to the semiconductor material to change its properties. By doping a semiconductor you can make two separate types of semiconductors in the same crystal. The boundary between the two types is called a p-n junction. The junction only allows current to pass through it one way, this is why they are used as diodes. LEDs are made using p-n junctions. As electrons pass through one crystal to the other they fill electron holes. They emit photons (light).

https://www.electrikals.com/

Answer 6

I don't think you can make one, but you can definitely use one in the project...just look up circuits...but if you don't want to use them here is a cool thing you can do...using light bulbs in a series or parrallel circuit show the difference of how the power is distributed in each circuit..one the bulbs will all be bright and the other dimmer because they either all get the same power or use it up as it goes down the line its kinda cool...