🔌 Basic Electricity - What is voltage?

Summary

This video script offers an insightful exploration of electricity, focusing on the concept of voltage. It explains voltage as a 'pushing force' that drives electron flow, or current, through a circuit. The script uses a practical demonstration with an electric motor and an adjustable power supply to illustrate how increasing voltage results in increased current and faster motor speeds. It also touches on voltage's role in transmitting data through electrical signals, emphasizing its dual utility in powering devices and conveying information. The explanation delves into the scientific definitions of potential energy, coulombs, and joules, clarifying that voltage is essentially the difference in electrical potential energy per unit charge between two points.

Takeaways

• 🔌 Current is the flow of electrons in a wire, and Amps (amperes) measure the number of electrons flowing past a point per second.
• 🔋 Voltage is a pushing force that causes electrons to move and create an electric current within a circuit.
• 🛠️ An adjustable power supply can generate various voltages and measure the current flowing through a device, like a motor.
• ⚡ When voltage is increased, more current flows, which can result in greater energy transfer and increased device performance, such as a motor spinning faster.
• 💡 Voltage can be used to power various devices like motors, light bulbs, and electronics, and also to carry information as electrical signals representing data.
• 📶 Different voltage levels can represent binary data, such as 0 volts and 5 volts for binary 0s and 1s in a communication system.
• 🔬 The concept of 'volts push amps' is a simplification; in reality, chemical reactions in a battery create voltage, which then pushes electrons due to the difference in charge.
• ⚖️ Voltage is defined as the difference in electrical potential energy per unit of charge between two points.
• 🔋 Electrical potential energy is the ability to do work, and it is measured in joules, which can represent various amounts of energy for different tasks.
• 🚀 The unit of charge is the coulomb, which simplifies the measurement of current as a flow of charge per second (1 ampere = 1 coulomb per second).
• 🔄 Voltage is always relative and measured between two points, making it a potential difference, and it's essential for understanding how energy is transferred in an electrical circuit.

Q & A

What is the basic definition of current in the context of electricity?

Current is the flow of electrons in a wire, and it is measured in Amps or amperes, which refers to the number of electrons flowing past a certain point per second.

What role does voltage play in an electric circuit?

Voltage acts as a pushing force within an electric circuit, forcing electrons to move and creating an electric current.

How does the adjustable power supply in the video help demonstrate the relationship between voltage and current?

The adjustable power supply allows the creation of various voltages, which is used to show that as voltage increases, more current flows through the connected motor.

What happens when the voltage supplied to the motor is increased?

When the voltage supplied to the motor is increased, more current flows, resulting in the motor spinning faster and doing more work.

How can voltage be used to carry information?

Different voltages can be used as electrical signals to represent data, such as binary 0s and 1s in a communication system, where 0 volts or 5 volts might represent these values.

What is the chemical reaction inside a battery that creates voltage?

The chemical reaction inside a battery creates a difference in electrical potential energy, leading to one side being more negatively charged than the other, which pushes electrons away and creates a flow of current.

What is the scientific definition of energy mentioned in the script?

In the script, energy is defined as the ability to do work, which could involve moving something or heating something.

How is electrical potential energy measured?

Electrical potential energy is measured in joules, a unit that can describe the amount of energy needed to do various tasks.

What is the significance of the term 'unit of charge' in the context of electricity?

The term 'unit of charge' refers to the coulomb, which is a standard unit of electric charge. One ampere is equivalent to one coulomb of charge flowing per second.

How is voltage defined in terms of electrical potential energy per unit of charge?

Voltage is defined as the difference in electrical potential energy per unit of charge between two points, meaning that for every coulomb of charge that flows, a certain number of joules of energy are transferred.

Why is voltage often referred to as potential difference?

Voltage is often referred to as potential difference because it is always measured between two points, indicating the difference in electrical potential energy between them.

Outlines

00:00

🔋 Understanding Voltage and Its Role in Electricity

This paragraph introduces the concept of voltage in the context of basic electricity. It explains that voltage, measured in volts, is like a pushing force that compels electrons to move, creating an electric current. The presenter uses an adjustable power supply to demonstrate how increasing voltage results in more current flowing through an electric motor, causing it to speed up. The paragraph also touches on voltage's use in transmitting data through electrical signals representing binary information. The underlying chemical reactions within a battery that create voltage are briefly mentioned, highlighting the flow of electrons in a complete circuit.

05:01

🔌 Deep Dive into Voltage: Definitions and Examples

The second paragraph delves deeper into the scientific definition of voltage as the difference in electrical potential energy per unit of charge between two points. It breaks down the concept of potential energy, explaining it as the ability to do work, and uses the example of a stretched elastic band to illustrate this. The paragraph introduces the unit of charge, the coulomb, and relates it to the flow of electrons (amps). It then explains how voltage is essentially the amount of energy transferred per unit of charge, using the example of a 1.5-volt battery to show that 1.5 joules of energy are transferred per coulomb. The explanation continues with practical examples of how voltage is measured and used in devices like motors and USB ports, emphasizing that voltage is always a relative measure between two points.

Keywords

💡Current

Current refers to the flow of electrons in a wire, which is a fundamental concept in electricity. In the video, current is described as the movement of electrons past a certain point per second, measured in amperes (Amps). The video script uses the analogy of current flowing through a motor to demonstrate how voltage influences the flow of electrons, showing that an increase in voltage results in an increased current, which in turn affects the motor's speed.

💡Amps or Amperes

Amps or amperes is the unit of measurement for electric current, defined as the quantity of electric charge passing a point in an electric circuit per unit time. In the context of the video, the term is used to explain the rate at which electrons flow past a certain point in a wire, with the script illustrating this by showing how different voltages affect the amperage in a motor circuit.

💡Voltage

Voltage is the driving force behind the movement of electrons in an electrical circuit, often described as a 'pushing force' in the video. It is measured in volts and is essential for creating an electric current. The script explains voltage through the use of an adjustable power supply, demonstrating how varying the voltage affects the amount of current flowing to a motor and its subsequent operation.

💡Electric Motor

An electric motor is a device that converts electrical energy into mechanical energy, often used in various applications requiring motion. In the video, an electric motor is used as an example to show the relationship between voltage and current. As the voltage supplied to the motor increases, so does the current, leading to an increase in the motor's speed, illustrating the direct impact of voltage on the motor's performance.

💡Adjustable Power Supply

An adjustable power supply is a device that provides a variable voltage and current to a circuit for testing and experimentation purposes. In the script, the adjustable power supply is used to create different voltages to demonstrate the effect on current flow and motor operation, showing that higher voltages result in more current and faster motor speeds.

💡Chemical Reaction

A chemical reaction is a process that transforms one set of chemical substances into another, often releasing or absorbing energy. In the context of the video, the chemical reaction inside a battery is what creates voltage, which in turn pushes electrons and creates an electric current. The script explains that the negative and positive charges within the battery repel and attract electrons, respectively, facilitating the flow of current.

💡Potential Energy

Potential energy is the energy an object possesses due to its position or condition, which can be converted into other forms of energy. The video script uses the concept of potential energy to explain electrical potential energy, which is the energy that has the potential to do work in an electrical circuit. The script provides the example of a battery having electrical potential energy due to the chemical reactions inside it.

💡Joules

Joules are the unit of measurement for energy, work, or amount of heat. In the video, joules are used to quantify the amount of energy that can be transferred or used to do work in an electrical circuit. The script explains that 1 joule is enough to power a flashlight for one second, and it uses joules to describe the amount of energy transferred per coulomb of charge in a circuit.

💡Coulomb

A coulomb is the standard unit of electric charge, representing the quantity of charge in a steady flow of electricity of one ampere in one second. The video script uses the concept of a coulomb to simplify the understanding of electric current, stating that 1 ampere is equivalent to 1 coulomb of charge flowing per second, making it easier to discuss the relationship between current and charge.

💡Electrical Potential Energy per Unit of Charge

This phrase refers to the amount of electrical potential energy available for each unit of electric charge in a circuit. The video script explains that this concept is central to understanding voltage, as it describes the energy transfer per coulomb of charge. The script uses the example of a 1.5-volt battery to illustrate that for every coulomb of charge that flows, 1.5 joules of energy are transferred.

💡Digital Signals

Digital signals are electrical signals used to represent binary data, typically consisting of two discrete voltage levels. In the video, the script mentions using different voltages as electrical signals to represent data in a communication system, such as 0 volts and 5 volts representing binary 0s and 1s. This demonstrates another application of voltage beyond just powering devices.

Highlights

Current is the flow of electrons in a wire, and Amps measure the quantity of electrons flowing past a point per second.

Voltage is a pushing force that causes electrons to move and create electric current.

An adjustable power supply can create any desired voltage for circuit design and learning about electricity.

Increasing voltage results in more current flow, which can be observed with an adjustable power supply.

Voltage can power various devices such as motors, light bulbs, and electronics.

Different voltages can represent binary data in communication systems.

Voltage can be used as a signal with minimal current flow for data transmission.

Voltage originates from a chemical reaction inside a battery, creating a difference in charge.

Voltage is the difference in electrical potential energy per unit of charge between two points.

Potential energy is the ability to do work, and energy is measured in joules.

A coulomb is a standard unit of electric charge, simplifying the measurement of current.

Electrical potential energy per unit of charge indicates energy transfer for each charge that flows.

Voltage is always relative and measured between two points, also known as potential difference.

Voltage can be used to power devices requiring high current or as a signal with minimal current for data.

Understanding voltage is crucial for designing circuits and comprehending electrical phenomena.

The video provides a practical demonstration of voltage's effect on current using a motor and power supply.

Voltage's role in both power delivery and signal transmission is highlighted through examples.

Transcripts

In my first video about basic electricity, you learned that current is basically the

flow of electrons in a wire.

And the term Amps or amperes refers to how many electrons are flowing past a certain

point per second.

In this video I'm going to first tell you what voltage does, then I'm going to explain

what voltage is.

There's an important difference!

Okay, the super simplified explanation of voltage is that volts push current around

an electric circuit.

Voltage behaves like a pushing force, forcing electrons to start moving around, which creates

an electric current.

Ok, I want to show you an example.

Over here I have an electric motor with some wires connected to it.

This fancy thing is an adjustable power supply.

It allows me to create nearly any voltage I want, which is

useful for designing circuits, but you don't need one of these to start learning about

electricity - you can just use batteries.

The voltage I'm generating will be shown here, and the fun thing about this power supply

is it can automatically measure how much current is flowing.

And that's going to be shown here.

I want you to see how when you increase the voltage

going to the motor, more current flows.

If we start out with the power supply set to zero volts, the motor doesn't do anything.

Now let's set the power supply to produce 1 volt.

Immediately you can see that there is current flowing - roughly 1.8 amps.

And when there's current flowing, energy can flow from the power supply to the motor.

Now let's increase the voltage to 2 volts!

Now that we have bigger pushing force, more current is flowing.

2 amps.

So more energy is flowing through the motor, so obviously it's going to turn faster.

And the more I crank up the voltage, we get even more current, and the motor speeds up.

Okay, that's just one example of what voltage does.

You can use a voltage source to power motors, light

bulbs, electronics and other things.

Another important example of what voltage can do is carry useful

information.

You can use different voltages as electrical signals that represent data.

In this example, 0 volts or 5 volts represents binary 0s and

1s in a communications system.

Now this is way more advanced than what I want to talk about in this video,

I just want you to understand that sometimes voltage is used

to power things that draw high amounts of current, but you can also use voltage as a

signal, and almost no current flows at all.

You just create the changing voltages with a transmitter, and detect the changing

voltages with a suitable receiver.

Now remember, the whole volts push amps thing is just a helpful simplification.

What is really going on here is that there's a chemical reaction inside

this battery that's creating a voltage.

This side of the battery is more negatively charged than the top of

the battery.

Negative charges repel negative charges, so this

side of the battery will push electrons away from it.

Electrons push other electrons, current flows, and the

electrons on the top side get attracted to the positive side of the battery, and everything

flows in a complete circuit.

Okay, I've been talking about what voltage does and how you can use it.

Now let's talk about what voltage actually IS.

Voltage is a difference in electrical potential energy, per unit of charge, between two points.

Okay, there's a lot to cover here, so let's break all these words down into their basic

definitions.

Let's start with the words potential energy.

Forget about hippies and feelings for a second, the actual

scientific definition of energy is the ability to do work.

The work could be moving something, heating something, things like that.

We say something has potential energy if it has the potential to do work.

For example, this stretched elastic band has elastic potential energy.

It's not doing anything right now, but it has the potential to do work.

If I released it, the elastic potential energy would be converted into

movement, which will propel the piece of paper into my target.

This battery has electrical potential energy.

It's not doing anything right now, but it does have the potential

to do work.

There's a chemical reaction inside it that creates electrical potential energy, and if

I connect this light to this battery, we form a complete

electrical circuit, current will flow, and (light blows up)

Hmm... a little too much current flowed...

I guess we need to learn more about electricity before we try

that again.

Anyway, those are some examples of potential energy and it's important to know that we

measure energy with units called joules.

Joules can be used to describe the amount of energy it takes to do a lot of

different things.

1 joule is enough energy to power this flashlight for 1 second.

3 joules is enough energy to power this flashlight for 3 seconds.

And 90,000 joules is the energy required to power this microwave for 1

minute to make a cup of tea.

We'll talk more about energy and joules later in the video.

Ok, so now you have an idea of what electrical potential energy means, what does this unit

of charge mean?

Well, do you remember how I was saying that electrons are negatively charged particles,

and 1 amp is 6.24 x 10^18 electrons flowing per second?

That's a really awkward number, and engineers hate using it.

Instead, we use a standard unit of charge, called the coulomb.

The total charge on 6.24 x 10^18 electrons is equal to 1 coulomb of charge.

And since electrons have a negative charge, this charge would be

negative.

You can see now that it's much easier to just say 1 ampere is equal to 1 coulomb of charge

flowing per second.

And 2 amps is 2 coulombs flowing per second.

Now let's tie these two concepts together.

When we talk about electrical potential energy per unit of charge, we mean that a certain

number of joules of energy are being transferred for

every unit of charge that flows.

For example, let's say this is a 1.5 volt battery.

That means that for every coulomb of charge that flows

from the battery, 1.5 joules of energy are being transferred.

1.5 joules of chemical energy are being converted into electrical potential energy.

Then this electrical potential energy or "voltage" pushes

electrons around the circuit, and for every coulomb's worth of electrons that flow, 1.5

joules of energy are getting delivered to the light bulb, and converted

into light and heat.

Now let's go back to my example with the motor.

With the power supply set to zero volts, no current can

flow.

But with a flick of a switch, now the power supply delivers 1 volt, or 1 joule per coulomb.

And over here, the power supply is measuring the amount

of current flowing through the motor.

It's roughly 1.8 amps.

1.8 amps means that 1.8 coulombs are flowing from the power supply every second, and for

every coulomb, 1 joule of energy gets transferred.

So 1 volt times 1.8 amps means that 1.8 joules of energy are

flowing through this motor every second.

If we increase the power supply's voltage to 2 volts, the higher voltage pushes more

current, and now we have 2 coulombs per second flowing.

2 volts multiplied by 2 amps means that 4 joules of energy are

flowing through this motor every second.

And of course with more energy flowing through the motor

every second, obviously the motor is going to do more work, and spin faster.

Ok, now that you understand energy per coulomb, let's go back to our definition of voltage

and talk about this part.

Voltage is the difference in electrical potential energy between two points.

In other words, voltage is always relative.

We all say this is a 9 volt battery, but that's not 100% correct.

What we are supposed to say, is that there is

an electrical potential difference of 9 volts between this negative terminal, and this positive

terminal.

There's a difference of 9 joules for every coulomb that flows out of the battery.

And that is what makes this a 9 volt battery.

Over here, in casual conversation we might say this is a 5 volt USB port.

But what we really mean to say is that there is 5 volts between this positive

power pin, and this negative power pin.

These two pins are used for sending digital messages, and there's

a rapidly changing 3.3 volts between them which carries the

information.

So voltage is always measured between two points, and this is why voltage is also sometimes

called potential difference.

That's right, voltage can sometimes be called potential difference, tension and a lot

of other names.

No wonder people get confused!

Ok, that was voltage, my next video will be linked over here.

In the meantime, subscribe, thumbs up, twitter, facebook, website yadda yadda yadda

you know what to do.