What is Electric Current?

Summary

Highlights

• Electric charges can build up and create static electricity or move in current electricity. ⚡️
• Copper, aluminum, and gold are great conductors for electron movement. 🏃‍♂️
• Electric current is measured in amperes, abbreviated as 'amps'. 🔄
• A voltage source is needed to push electrons through a wire and create current. 🔋
• In circuits, current traditionally flows from positive to negative, known as conventional current. 🔄

Key Takeaways

• Electric current is essential for modern electronics, moving charges through conductors. ⚡️
• Conductors allow easy electron movement, creating a flow known as electric current. 👨‍🔬
• Voltage sources like batteries push electrons to flow, enabling electric circuits to function. 🔋
• Understanding the difference between conventional current and electron flow is crucial. 📘
• Circuits form the foundation for all electronics, from simple to complex systems. 💡

Overview

Chapters

• 00:00 - 00:30: Introduction to Electric Charges The chapter introduces the concept of electric charges, explaining their ability to build up on surfaces and generate static electricity. The focus then shifts to what transpires when these charges move continuously, a phenomenon known as current electricity, which is essential for operating most electronic devices like refrigerators and smartphones. The example of copper wire filled with copper atoms is used to illustrate the presence of a single electron in its outer shell, highlighting copper's role in conducting electricity.
• 00:30 - 01:00: Electrons in Conductive Materials The chapter explains the concept of electron movement in conductive materials. It begins by describing how a small amount of energy can eject electrons from atoms, using copper as an example. When a free electron is introduced into a conductive material like copper, it displaces another electron, creating a chain reaction. This movement of electrons from one atom to another results in electric current. The chapter highlights that certain elements, such as copper, aluminum, and gold, facilitate easy electron movement and are classified as conductors.
• 01:30 - 02:00: Electric Current and Amperes Chapter Title: Electric Current and Amperes Summary: The chapter explores the concept of electric current through the analogy of moving charges using conductive wires and steel balls as electrons. It explains that for an electric current to be present, it is not necessary for a charged particle to move completely through a conductor. Instead, when one electron is pushed from one end, it causes all the other electrons to move along the conductor, demonstrating the collective movement of charges.
• 02:30 - 03:30: Role of Voltage in Electric Current The concept of electric current as a flow of electric charge is introduced. In typical circuits, electrons are the charges that move. Current is measured in amperes (amps), with 1 ampere equating to 1 coulomb of charge passing a point per second. The chapter provides an example using a cross-section of wire to demonstrate the movement of charge.
• 03:30 - 04:00: Open vs Closed Circuits This chapter explains the concept of electric current and how it requires a voltage source to move through wires. It begins by describing that electric current is measured in amps and does not flow through wires on its own. Electrons need a 'push' from a voltage source like a battery. A battery creates a buildup of negative charge (excess electrons) on one side and positive charge (lack of electrons) on the other, which creates the necessary conditions for current flow.
• 04:00 - 05:00: Conventional Current vs Electron Flow This chapter explains the difference between conventional current and electron flow. Conventional current is the flow of positive charge, which is in the opposite direction to the flow of electrons, which are negatively charged. The chapter highlights the need for a complete circuit for electrons to flow. It describes an experiment where a wire is connected to a battery and discusses the behavior of electrons when the circuit is open versus when it is closed.
• 05:00 - 05:30: Summary and Teaser for Next Episode In this chapter, the concept of a closed circuit in electrical systems is explained. A closed circuit allows electrons to flow continuously from the negative to the positive end of a battery, potentially creating a dangerous amount of energy and heat if not properly managed. The chapter warns against testing this with a real battery due to the risk of melting the wire or starting a fire. Breaking the circuit or removing a wire halts the flow of electrons, illustrating the importance of a proper connection for electricity to flow.

What is Electric Current? Transcription

• 00:00 - 00:30 ♪ ♪ >> Previously, we talked about how electric charges can build up on surfaces and create something known as "static electricity." In this episode, let's talk about what happens when these electric charges continuously move in a process known as "current electricity." Most electronics, everything from your refrigerator to your smartphone, requires current electricity to operate. Let's assume that we have a copper wire that's filled with copper atoms. Copper is one of those elements that has only one electron in its outermost shell,
• 00:30 - 01:00 which means that with only a little energy, that electron can be easily ejected. If we push a free electron into the copper wire, it will eventually find a new atom to latch onto. The negative charge of that electron will eject another electron from the outer shell, which will then move on to the next atom, and so on and so on. This chain of moving electrons creates a flow known as "electric current." Some elements like copper, aluminum, and gold can move electrons easily and are known as "conductors."
• 01:00 - 01:30 We can look at moving charges in another way. Let's say that this tube is a conductive wire and the steel balls are negative electric charges-- electrons, in this case. We might think that one charged particle needs to move completely through the conductor to create a flow, but that's not actually the case. As we push a ball in one end, the force causes all the balls to move, and one pops out the other end. As you can see, one electron, even if it doesn't move very far, can force all the other electrons to move,
• 01:30 - 02:00 creating a flow. What we just showed was electric current, which is a flow of electric charge. In most circuits, this is accomplished by moving electrons. The unit for measuring current is the ampere, which is often abbreviated as "amps" and written with a capital A. 1 ampere is defined as 1 coulomb of charge moving past a point per second. Let's look at a cross-section of wire carrying an electric current. If it takes 3 seconds for 6 coulombs of charge to move through that cross-section,
• 02:00 - 02:30 then we say that 2 amps are moving through that wire. Unfortunately, electric current doesn't just magically flow through wires. It needs a little help. If left alone, the electrons in a wire won't move. We need to give them a little push. To do that, we'll use a voltage source like a battery. In a battery, there is a buildup of negative charge on one side in the form of excess electrons. The other side has a buildup of positive charge, an absence of electrons in this case. The charges want to balance out, but the only way to do that is for the excess electrons
• 02:30 - 03:00 to flow around the battery through a conductor that we provide. If we connect a piece of wire to the negative terminal, the electrons will push against the electrons in the wire. However, air is an insulator as its molecules do not have very mobile electrons and it won't readily accept the free electrons. To show this, we'll put a piece of tape at the end of the tube. Now, the electrons at the end of the wire have nowhere to go. Even if we push against the electrons in the wire, they still won't budge. To fix this, we need to connect the other end of the wire
• 03:00 - 03:30 to a place where the electrons want to go, and the positive end of the battery will happily accept the electrons. In fact, don't try this with a real battery. There is nothing slowing down or restricting the flow of electrons, which results in tremendous amounts of energy being transformed into heat in the wire, and this could easily melt the wire insulation or start a fire. (fire crackling) This is known as a "closed circuit," as it creates a loop from one side of the energy source to the other. If we break the wire or remove it from one of the terminals, then the electrons will stop flowing.
• 03:30 - 04:00 This is known as an "open circuit." We've been talking about electron flow in a circuit, and showing how electrons move from the negative terminal to the positive terminal. However, in electronics, we usually assign current as flowing from positive to negative, or from higher potential to lower potential. This is known as "conventional current." In the mid-1700s, Benjamin Franklin theorized that positively charged objects had an excess of what he called "electric fluid," and that negatively charged objects
• 04:00 - 04:30 had a deficit of this fluid. Franklin noted that this fluid had a tendency to flow from positive to negative to distribute itself more evenly. It wasn't until the end of the 19th century that English physicist J.J. Thomson discovered the existence of the electron. Even though we now know that it is electrons that move inside of most circuits from low to high potential, the convention of current moving from high to low potential stuck. As a result, most current measurements are given as conventional current, which is the movement
• 04:30 - 05:00 of positive charge in a circuit and is represented by the capital letter I. Don't worry the math still works out, as long as we stick with either electron flow or conventional current. And since most electronics textbooks use conventional current, we'll go with that. We talked about making electricity do work for us, and the circuit forms the basis for all modern electronics, everything from the simple flashlight to massive supercomputers. If we made a circuit out of just a battery and a piece of wire, there's a chance we might melt that wire as the electrons move through that wire
• 05:00 - 05:30 at an alarming rate and generate massive amounts of heat. In the next episode, we'll talk about the relationship between voltage and current, and introduce the resistor. ♪ ♪