How did this Lab experiment work exactly?

[denjay]

In my intro Electromagnetism physics class, one of the labs we did was really fascinating. I didn't have a huge amount of interest in it at the time so I don't remember the details of how it worked but now I really want to know.

From what I remember the set up was like this:

We hooked up a microphone to some circuit with an LED. This LED would flicker depending on what sound was input into the microphone. The LED then was held up to what I remember as a solar panel or something similar. The solar panel was attached to another circuit with a speaker. Essentially it transferred the sound from the microphone to the speaker through the flickering of the LED.

Does anyone have an idea of what this is called? I'm assuming it's related to fiber optics in some way but it was a very simple set up that looked like you could make at home with some electronic supplies. Any details would be greatly appreciated.

 

[Windadct]

You just made a basic optical transmitter (led) and receiver (solar panel) - very much the same as the typical TV remote control - but with visible light instead of IR. I would not have thought that you would get enough energy transfer - through a systems like that to actually be able hear anything on the other end - I' think I might try that one!

 

[Mordred]

lol not many ppl know this but you could use that same LED as a light senser.

 

[denjay]

What supplies would one need to make this?

 

[Windadct]

Hello Den...

Ha I had to laugh at how poorly I read your original post-sorry. I was thinking you ONLY had the Micro/LED then Solar Panel and Speaker. But the Microphone ->small amplifier -> LEDs

The solar panel (cell) may be able to go right to a speaker. I'll bet all available at something like Radio Shack - depending on the distortion levels you would be OK with.

Ether way - with some type of an amplifier(or 2) involved - I can clearly see how this would work.