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Paper Mache Class
This is basically the same technology used to turn cream into ice cream. You have made a mini ice cream maker.
I've been looking at meteorites on Ebay just last week! And knives made out of meteorite. What a great project idea!
There are many interesting and exciting things about this circuit. First of all, I didn't realize a 5mW red laser diode could burn like that! But one lesson, other than the interesting laser diode, would be the simple negative feedback to the LM317, by putting the Vadj AFTER the resistor, in order to regulate thermal runaway. I know it's a simple principle, but still interesting and important to electronics where you want current regulation. Just off the top of my had, I imagine someone could introduce a Zener diode in parallel with a resistor to regulate Iout.
Even though the circuit looks simple, it has a lot of interesting lessons, like the Hall effect sensor, and inductance, and magnetism, and the use of super magnets. Makes me want to relive my mad scientist days from 25 years ago.
If I were to reproduce this experiment, I would skip the battery driven transistor, and go straight for rectifying radio signals right out of the air. If anyone has ever been burned or shocked touching a radio antenna, you know that radio waves transmitted through the air are converted to electricity in a coil.
I'm not commenting on the semiconductors so much as the use of the battery. The circuit in this article is a fine example of oscillation tank and air core transformer.With a radio wave as the Vsource, we would have to use a germanium or selenium diode because of its low breakover voltage. That alone would probably not light up an LED, but if we could store the potential in a capacitor, it might charge enough to discharge into an LED.
Basically, this is a transformer with an air core.
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