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PAPER GENERATORS

Annika and Henry.

11/16

We attempted to generate electricity using paper-like materials. To start out, we replicated a power harvesting method introduced by Disney Research in 2013.

Materials

We used a Mylar film, a Teflon (PFTE) sheet, a Vishay DF10S rectifier, conductive tape, and a red LED – red LEDs require the least amount of voltage, ~1.2V.

Setup

To set up the paper generator, we taped the Mylar film onto a piece of paper. Then, we connected the film to the positive input on the rectifier using a piece of conductive ribbon tape. We connected a wider and longer piece of conductive ribbon tape to the negative input of the rectifier (to serve as GND). Lastly, we connected the LED to the rectifier, matching up the rectifier's positive and negative outputs with the LED's positive and negative sides.

In this setup, the Mylar film is an electrode (a.k.a. an electric conductor that carries electricity and is used to make contact with non-metallic parts of a circuit) and the Teflon is used to induce charge to generate electricity. First, we rub a crumpled piece of paper against the Teflon sheet to positively charge the Teflon. Next, we rub the Teflon sheet against the Mylar film. Because the Teflon sheet is positively charged, it attracts electrons thereby generating a static voltage. Wait, don't electrons flow from the positive terminal to the negative terminal?! No, current flows from the negative terminal to the positive terminal. Flow from positive to negative is just a convention. Check it out here. The static voltage is converted into DC electricity by the rectifier. You can read about charging by friction and charging by induction here.

As you can see in the above video, we were unable to create enough voltage or current to light up the LED. The maximum amount of voltage we were able to produce was 0.25V.

So we added some capacitors which store charge. The capacitors charge up until there is enough current to power the LED. At this point, the LED briefly lights up, using up the available energy from the capacitors. But wait, what about the voltage?! Don't we also need more voltage?! I don't have an explanation for this. Capacitors store energy in an electric field wherein protons and electrons are separated by a dielectric field (a non-conductive barrier). The electrons want to cross the dielectric material and eliminate the electric field, but they can't. The electrons in the electric field represent charge. Perhaps the attempt to eliminate the electric field might be considered potential energy and therefore voltage?


11/17

To make the LED light up for a longer duration, we added a 220-ohm resistor and a switch. The switch allows us to control when the capacitors can discharge. That is, the switch toggles whether the current flows through the LED or not. To make it easier to connect all of the components, we used a breadboard. Our final setup is shown in the picture below.

paper_generator.txt · Last modified: 2019/11/24 20:57 by radical