 Hi, today we're going to talk about resistors. Resistors are one of the most basic and commonly used electronics components in any sort of project. Now we're going to learn about how resistors are made, how they work, and how we can use them in different projects and circuits. Now, if you want to think about resistors, we should look at the name. As the name implies, resistors resist electricity. More specifically, they resist the flow of electrons. Now, if you think of electricity as water, you can think of a resistor as a clog inside a water pipe. It's like a clog would slow down the flow of water. A resistor would also slow down the flow of electrons. Resistors are made by wrapping a thin metal conductive strip around an insulating block like this. Now, there's three main types of resistors. Carbon resistors, metal resistors, and metal oxide film resistors. With metal and metal oxide film resistors being the common types. Now, there are also special types of resistors called variable resistors. These can be sliders or potentiometers like your normal knobs. And how these work is by having a partially conductive strip and moving our electrical contact along that partially conductive strip. By moving this electrical contact, we shorten or lengthen the amount of contact or the amount of partially conductive strip that electricity is flowing through. And by lengthening or shortening this, we can increase or decrease our resistance. The unit for resistance is ohms. And the symbol used for resistors in circuit diagrams looks something like this. This is the American symbol and this here is the international symbol. Now, both symbols are commonly used so you can use either one of them. Now, if you wanted to read the value of a resistor, if you look carefully, you will see four to six different colored bands on the resistor. If you input these bands into an online calculator or chart that looks like this, we can understand what the resistance value of a resistor is, including its tolerance level. Now, let's talk about some of the use cases of resistors. The first use case of a resistor is to limit current. Using ohms law like here, we can actually input our voltage and the current that we want and then using that we can determine the resistor value that we should be using. Furthermore, if we wire our resistor in series to our circuit, the overall resistance of the circuit increases, but if we wire our resistor in parallel to our circuit, the overall resistance of the circuit will decrease. We can also use resistors as voltage dividers. By wiring two of these resistors in series, we can induce a voltage drop at the middle point of the two resistors as in the point where the two resistors meet. We can calculate this voltage drop using ohms law again. The last common use case for these resistors is as a pull up or pull down resistors. Microcontrollers such as the Arduino or Raspberry Pi here have digital input and output pins. When we connect sensors, digital sensors to these input or output pins, sometimes that can introduce a little bit of digital noise. So when we use these resistors, usually a high value resistor like a 10k resistor, that means a 10,000 ohm resistor, when we attach these resistors to our digital pin and connect it to either 5 volts, which is a pull up or ground, which is a pull down resistor, then what we can do is basically stabilize the input pin of the microcontroller and basically eliminate any digital noise, making the signal from the sensor a lot cleaner. I hope you enjoyed this short little crash course. We're just scratching the surface of what resistors can do and what they're used for. If you want to watch more tutorials like this, do subscribe and if you have any questions, you can leave them down in the comments section below. Thanks for watching.