Circuits
An electric circuit is made of elements. Elements include at least one source. The source is connected to a bunch of components. Sources provide energy to a circuit, making it power on. The two main sources are Voltage and Current. First, we will talk about Charge. The force between objects that act at a distance is called charge. There are two types of electrical charges. Opposite types of charges and like types of charges repel. Knowing about charges, we will now talk about Conductors and Insulators. Conductors are made of atoms whose outer, or valence, electrons have relatively weak bonds to their nuclei. When a bunch of metal atoms is together, they form a “swarm” of electrons. A very small electric force can make the electron swarm move. Copper, gold, silver, and aluminum are good conductors, as well as saltwater. There are also poor conductors. Tungsten—a metal used for light bulb filaments—and carbon—in diamond form—are relatively poor conductors because their electrons are less prone to move.
Insulators are materials whose outer electrons are tightly bound to their nuclei. Modest electric forces are not able to pull these electrons free. When an electric force is applied, the electron clouds around the atom stretch and deform in response to the force, but the electrons do not depart. Glass, plastic, stone, and air are insulators. Even for insulators, though, electric force can always be turned up high enough to rip electrons away—this is called breakdown. That's what is happening to air molecules when you see a spark. Semiconductors fall between insulators and conductors They usually act like insulators, but you can make them act like conductors under different circumstances. The most well-known semiconductor is Silicon, which we use to control the insulating and conducting properties of it to create mobile phones and computers.
Current is the flow of charge. Current can also be stated as the number of charges per unit time passing through a boundary. Visualize placing a boundary all the way through a wire, then station yourself near the boundary and count the number of charges passing by. See how many charges passed through the boundary in 1 second. Since the current is the amount of time a charge passes through a boundary, it can be expressed mathematically with the expression: i = dq/dt. The d is a notation from calculus, and an easy way to put it is “a tiny change in…”. Learning that, you can figure out that dt means “a tiny change in time,” and for dq it would mean “a tiny change in charge.” The variable q is a charge.
The next term we'll learn is Voltage. To get a good idea about voltage, it’s kinda like gravity. For a mass that will be represented by m, a change of height (h), corresponds to the change of potential energy. This can be represented by the expression of ΔU=mgΔh. A charged particle q, a voltage V corresponds to a change in potential energy, ΔU=qV. A ball at the top of the hill rolls down, and when it reaches halfway down, it loses or gives up its potential energy. An electron at the top of the voltage “hill” travels “downwards” through wires and elements of a circuit. When the electron reaches half-way “downhill”, it loses half of its potential energy. The comparison between the ball and the electron, they both move towards a low energy state all by themselves. While going downhill, there can be things that can be in the way of the ball, like bears and trees. For electrons, we can guide them using wires and make them flow through electronic components, and make them do interesting things.
And finally, the last term before the article ends that we will be talking about is Power. Power is defined as the rate of energy (U) that is transformed or transferred over time. You measure power in units of joules/second, also known as watts. 1 watt = 1 joule/second. An electric circuit is capable of transferring power. Current is the rate of flow of charge, and voltage measures the energy transferred per unit of charge. We can insert these definitions into the equation of power: Power = dU/dt = dU/dq * dq/dt = v i. Electrical power is the product of voltage times current in units of watts.
This is a short summary of the main components of circuits. I hope you liked it and enjoyed it!
Resource(s):
https://www.khanacademy.org/science/electrical-engineering
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