Part I: The Basics and Recreating Circuits
Week 2 was the first official week of the minor, after the kick-off week. This week was all about the basics of electronics.
We started this week with a tutorial on connecting and debugging circuits. We learned about basic electronic circuits, and the laws that exist within those circuits. Those laws are:
Kirchhoff's first law: at any given junction within an electric circuit, the sum of the energy coming into that junction is equal to the sum of the energy leaving that junction. Within a junction, no energy can be stored or given away.
Kirchhoff's current law: the current within an electric circuit is the same at any given point.
Kirchhoff's voltage law: all of the voltage that is generated must be used up by components within the circuit.
Ohm's law: Ohm's law can be explained using a simple formula: V = I * R, where V is the voltage in volts, I is the current in ampere and R is the resistance in ohm. Knowing that the current is always the same within a circuit, the voltage and resistance have to be connected in some way. The higher the resistance at a certain point in the circuit, the higher the voltage will be. It's the same the other way around: the higher the voltage is, the higher the resistance will be. If you use the formula to calculate the current (I = V / R), you will only have to do this one time, since the current will be the same at any point in the circuit.
Using these laws, we were given the task to recreate three relatively simple circuits: an LED, an LED with a dimmer and parallel LEDs. First we will discuss the LED.
The image above shows the LED circuit. To make this circuit, I used copper tape (copper is a conductive metal, so energy can flow through it), a 3V battery, a resistor and a LED light. The circuit is completed by folding the folding line so, that both the anode (+) and cathode (-) are connected to the copper tape. You can connect the resistor any way you want using the copper tape, but the LED has a specific positive and negative wire. The positive wire is longer that the negative one, so it can be easily identified. Below shows different images of the LED working.
As shown in the picture above, the LED behaves differently, depending on the resistor that is connected. Ohm's law teaches us that, if the resistance is lower, the current will be higher. A higher current will result in a brighter light (I = V / R). Making this first circuit gave me no trouble. Now let's take a look at the second circuit: the LED dimmer, shown in the image below.
A lot of the circuit shown above works the same as the first circuit I made. A 3V battery, a resistor and a LED light are all connected in a circuit with copper tape. There is however a new component introduced here: a piece of velostat tape. Velostat has a unique property: its resistance changes depending on the amount of pressure that is applied. The more pressure, the lower the amount of resistance will be. The first circuit has taught us that a lower resistance will result in a brighter light, thus making a piece of velostat tape an ideal way to make a dimmer. When pressure is slowly applied to the tape, the light will slowly increase in intensity, as shown in the GIF below.
The last circuit I made is a circuit with parallel LEDs, shown in the image below.
For this circuit, no new components were introduced. The only thing that differs this circuit from the first one is the second LED that is connected parallel to the first one. The second LED however, is only connected at the positive leg.The first LED will light up normally if the battery is connected by both sides. If the negative leg is connected to the copper tape, the second LED should light up as well. However, mine didn't light up. Another law within circuits like these is that the electricity will always choose the route with the lowest resistance. Because I used LEDs with different resistances (a different color means a different resistance), and the green LED had a higher resistance than the yellow LED, the electricity will only flow through the yellow LED, causing the yellow LED to light up and the green to not light up. If I had used two of the same LEDs, it would have worked as desired.
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