ok, so i just had a lot typed up, ran the spell check, tried to backspace a word and the stupid thing backed out of the entire post and erased it all! ughh!! Let's try again shall we. (hit save button now)
So we have done 3 labs so far. The throwie lab, the one using a 9v to light an LED, and the blinky light lab.
The throwie was by far my favorite. It was the easiest to understand and to execute. You just have to touch the legs of the LED to the correct sides of a coin battery to make the LED light up. Add a small magnet and tape it all together and you have a throwie, which is basically a magnetic light that you can throw at a magnetic surface for hours of simple amusement. These neat little things are often used in graffiti which is totally awesome. It was mentioned in class that we, as a class, should make a bunch of these and go out to do a collaborative graffiti work. Im all for it! (hit save here)
I found on the instructables web site, a way to make the throwie so that the light comes on when it sticks to a surface instead of staying on all the time. It was very simple. You just had to put in a barrier so that the leg of the LED only made contact with the battery when the devise was magnet was engaged. I altered my throwie to this design. I was totally accomplished! (save now)
I showed the throwie to my boss at the youth center. We might possibly do this little project at work with the kids. It would be a great community performance art piece!
The second lab was very similar. This time no magnets but still lighting an LED. Instead of a coin battery, we used a 9 volt battery. Since we were using 9 Volts we had to also use a resistor. The LED can only handle 3 volts with out blowing the circut so the resistor must be used to control the flow of the voltage so that the right amount of power reached the LED. We got to experiment completing the circuit with a piece of copper tape and a strip of graphite. Both materials are conductive and carry the voltage, but the copper tape is more efficient. The copper carries the power so that the LED maintains the same level of brightness as it has when the circuit os completes by touching the legs of the LED and the resistor together. The graphite only completes the circuit when the legs of the LED and resistor are close together and even then,the light is very dull. So copper is has less resistance than graphite. (save)
The blinky light lab was difficult and I didnt even finish it. We used a diagram to arrange parts on a bread board to make 2 LEDs blink on and off. It took me 3 attempts to get the circuit to work, and i still dont understand exactly how it works. We experimented completing the circuit with alternate parts:
control group:
120k and 33k resistor and capacitor value 4.7
-with a 120k and a 33k resistor and a capacitor value of 10 the lights flash slower (about every second) and stay lit slightly longer
-with a 120k and 33k resistor and capacitor value 22 the lights blink slower (about every 4 seconds) and the lights stay lit longer ( for about a second)
-with a 120k and 10k resistor and capacitor value 4.7 the lights blink faster and don't stay lit as long
-with a 120k and 10k resistor and capacitor value 10 the lights blink every 2 seconds but stay dont stay lit as long
-with a 120k and 10k resistor and capacitor value 22 the lights blink every 4 seconds but they barely stay lit
so... the capacitor seems to control how often the lights come on: the lower the number, the more frequent = frequency
....and the resistors seem to control how long the lights stay on: the more resistance the longer it stays lit = duration
I didnt get to the soldering yet...next time (save)
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