In this lab, the objective was to build two circuits: one that had two LEDS in parallel, and one that had the two LEDs in series. Each circuit also included a voltage regulator, power source (9V), and resistors.
The first circuit that I built was the circuit in series. Series means that the LEDs are “in a line” like ducklings following their mom duck. When components are in series, the voltage is divided between them, though the current is not. I used red LEDs, which need two volts of energy each.
To begin actually building the circuit, I first drew the schematic and calculated the resistance necessary (I got 50 ohms).
Next, I actually built the circuit. I had a bit of trouble identifying the pins for the power source, which caused my first attempt to fail. After looking up the pinout, struggling for a bit, and rearranging things, I figured it out.
After this, I built the parallel circuit. When components are in parallel they are “next to each other”. They don’t actually have to be next to each other in physical proximity, but the difficulty of getting to either of the LEDs for the electricity is about the same. In a parallel circuit, the current is split, not the voltage.
Again, I started by drawing the schematic and calculating the necessary resistance (75 ohms in this case).
For this circuit, I only had to move a few things from my series circuit, so the actual construction was pretty quick.
Next, we were supposed to build our own switch. I ended up building two because they are really finicky, and I wanted to make something more reliable.
For the first switch, I just took two small square pieces of foam, used the conductive copper tape to attach the wires, and stuck the copper tape (and wires) to the foam. Then, I placed another piece of foam with a hole cut in the middle between them, so they only touch if the foam in the center is compressed.
You have to pinch the foam really hard, and in just the right place (which seems to move) to get the switch to work, but nonetheless, here it is:
Then, I started on my enclosure. In the process of building the enclosure, I realized that it was really annoying to have to pinch the switch so hard (and my enclosure couldn’t support that much pressure). Because of this, I built a second switch. This one is essentially the same as the first, but made of cardboard, and there is no central piece of foam. It has a hinge, so when you want the circuit to be closed, you just hinge the switch closed so the copper tape touches. This switch works slightly better, but is still not as reliable and sensitive as I would like it to be.
Regardless, I built my little enclosure (it is a lighthouse!! Even though it looks more like the Eye of Sauron…) and it illuminates.
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