Voltage Explained - What is Voltage? Basic electricity potential difference

Summary

In this educational video, Paul from TheEngineeringMindset.com explains the concept of voltage, its role in driving electron flow in circuits, and how it's measured. He contrasts direct current (DC) with alternating current (AC), discusses the significance of voltage levels in different countries, and highlights the importance of matching voltage requirements with electrical devices to avoid damage. The video also touches on the historical reasons behind varying voltage standards worldwide.

Takeaways

• 🔌 Voltage is the force that pushes electrons in a circuit, similar to water pressure in a pipe.
• ⚡ Voltage can exist without current, much like pressure in a pipe with a closed valve.
• 💡 Potential difference, or voltage, is the energy that can be harnessed to do work, akin to water flowing from a higher to a lower lake.
• 🔋 Batteries provide a potential difference, and connecting them in series increases the voltage, boosting the pushing force for electrons.
• 🔗 Connecting batteries in parallel divides the workload, maintaining the voltage but reducing the pushing force and brightness of devices like lamps.
• ⚖️ Voltage is measured in volts (V), a unit named after physicist Alessandro Volta, who invented the first electrical battery.
• 🔍 A voltmeter or multimeter can measure the potential difference or voltage in a circuit.
• 🌐 Voltage and current requirements vary by device, indicated by a voltage rating often found on electrical appliances.
• 🌍 Voltage standards differ worldwide, with regions using either 110-127V or 220-240V for wall sockets.
• 🔄 Alternating current (AC) in wall sockets has a changing polarity, unlike direct current (DC) from batteries, which flows in one direction.
• 🛠 Devices designed for different voltages can be incompatible when used across regions with varying standards without proper converters or multi-voltage designs.

Q & A

What is voltage and why is it important in electrical circuits?

Voltage is the force that pushes free electrons around a circuit, causing them to move in the same direction and create current. Without voltage, electrons move randomly and are not useful for conducting electricity in a controlled manner.

How can voltage be compared to pressure in a water pipe?

Voltage can be imagined like pressure in a water pipe. A full water tank exerts more pressure than a partially filled one. Similarly, a higher voltage provides more 'push' for electrons to flow, akin to water flowing faster from a high-pressure tank.

Can voltage exist without current?

Yes, voltage can exist without current. For example, when a battery is connected to a circuit with an open switch, the voltage is present but no current flows until the switch is closed.

What is meant by potential difference in the context of voltage?

Potential difference refers to the amount of work that can potentially be done by a circuit. It's the difference in voltage between two points, similar to the difference in water levels in a water system that can do work.

How does connecting batteries in series affect the voltage in a circuit?

When batteries are connected in series, the voltages add up, providing a combined pushing force that results in more electrons flowing and a brighter lamp in the circuit.

What happens when batteries are connected in parallel in a circuit?

In parallel, the path of the electrons splits, with some flowing to each battery. The batteries provide the same amount of energy, but the voltage remains the same, resulting in a dimmer lamp that lasts longer.

What unit is used to measure voltage and what does it signify?

Voltage is measured in volts, symbolized by a capital 'V'. It signifies the potential difference between two points in a circuit.

Who is Alessandro Volta and why is the term 'volt' named after him?

Alessandro Volta was an Italian physicist who invented the voltaic pile, the first electrical battery capable of providing a steady current in a circuit. The term 'volt' is named in his honor.

How is voltage measured and what tool is commonly used for this purpose?

Voltage is measured using a voltmeter, which can be a standalone device or part of a multimeter. It measures the potential difference between two points in a circuit.

What is the difference between direct current (DC) and alternating current (AC)?

Direct current (DC) is a type of electrical current where electrons flow in one constant direction, similar to water flowing down a river. Alternating current (AC) is where the flow of electrons periodically reverses direction, akin to the tide of the sea.

Why do voltages vary around the world and what are the implications?

Voltages vary due to historical reasons and lack of standardization when electricity first started being distributed. This has implications for the compatibility of electrical devices, which can be damaged or underperform if used in regions with different voltage standards.

Outlines

00:00

🔌 Understanding Voltage and Its Basics

This paragraph introduces the concept of voltage, explaining it as the force that pushes electrons in a circuit, similar to water pressure in a pipe. Voltage is essential for creating a directional flow of electrons, which constitutes current. The analogy of water pressure is used to illustrate how voltage affects the rate of current flow. The potential difference, or voltage, is likened to the head of water between two lakes, indicating the work that can be done. The paragraph also discusses how voltage can exist without current, like measuring water pressure with a closed valve, and how voltage is measured in volts, named after Alessandro Volta. It concludes with the idea that voltage can be combined in series for a higher push or in parallel for a longer duration but at a dimmer light, referencing further details available in the Electrical Circuit series.

05:01

🔋 Exploring Voltage Measurement and its Impact on Devices

This section delves into how voltage is measured using a voltmeter and the significance of voltage in powering electrical devices. It explains that a single battery provides a constant voltage to a device, such as a lamp, and how the voltage is divided when multiple devices are connected in series. The concept of one volt is further clarified as the potential to drive a specific quantity of electrons through a resistance. The paragraph also discusses the consequences of using incorrect voltage levels on devices, such as dimming or burning out lamps, and introduces direct current (DC) and its representation, contrasting it with alternating current (AC) found in wall sockets. The explanation of AC voltage includes its characteristic sine wave when plotted over time. The paragraph concludes with a brief mention of the varying voltage standards around the world and the historical reasons behind these differences.

10:02

🌐 Voltage Variations and Global Electrical Standards

The final paragraph addresses the differences in voltage standards across the globe, highlighting the majority use of 220 to 240 volts, in contrast to 110 to 127 volts in North, Central America, and some parts of South America. It explains the historical lack of standardization and how market dominance and government regulations contributed to the current situation. The paragraph emphasizes the impracticality of changing these standards due to the reliance on existing electrical devices. It provides examples of how devices rated for different voltages can either burn out or underperform when used in regions with mismatched voltage levels. The paragraph also mentions the importance of checking a product's voltage rating and concludes with an invitation for viewers to continue their learning journey through recommended videos and social media platforms.

Keywords

💡Voltage

Voltage, in the context of the video, is the force that pushes free electrons around a circuit, causing them to move in a directed manner and generate current. It is essential for the functioning of electrical circuits as it provides the necessary energy to perform work. The video uses the analogy of water pressure in a pipe to explain voltage, where a higher voltage equates to greater pressure, resulting in more current flow. Voltage is measured in volts and is symbolized by 'V'.

💡Potential Difference

Potential difference, also referred to as voltage, is the measure of the work that can potentially be done by a circuit. It is the energy per unit charge available to move the electrons. In the script, potential difference is likened to the difference in water levels between two lakes, where a higher lake has the potential to do work by flowing down to a lower one, similar to how a higher voltage can drive more current through a circuit.

💡Direct Current (DC)

Direct Current (DC) is a type of electrical current where electrons flow in a constant direction, similar to the flow of water in a river. The video mentions that batteries provide direct voltage, meaning the electrons move from the negative to the positive terminal without reversing direction. DC is typically represented by a straight line when plotted against time, indicating its constant nature.

💡Alternating Current (AC)

Alternating Current (AC) is a type of electrical current where the direction of electron flow changes periodically, akin to the tide of the sea. The polarity of the circuit changes, causing the electrons to alternate between moving forward and backward. AC is represented by a sine wave when plotted against time, reflecting its cyclical nature. The video explains that the voltage in wall sockets is AC, which varies slightly throughout the day.

💡Current

Current in the video is described as the flow of free electrons within a circuit, which occurs when voltage is applied. It is the movement of charge that enables electrical devices to operate. The video illustrates that without voltage, electrons move randomly and do not create a useful current. Voltage and current are directly related, with more voltage leading to more current flow.

💡Electrical Circuit

An electrical circuit, as discussed in the video, is a closed loop through which electrons flow from a power source, such as a battery, through electrical components, and back to the power source. Circuits are necessary for the organized flow of electrons and the performance of electrical devices. The video explains how voltage applied to a circuit directs the flow of electrons and enables them to do work.

💡Ohm's Law

Ohm's Law, while not explicitly mentioned in the video, is implied through the explanation of voltage and current. It states that the current through a conductor between two points is directly proportional to the voltage across the two points and inversely proportional to the resistance between them. The video describes how voltage drives the flow of electrons (current) and how resistance affects this flow.

💡Voltmeter

A voltmeter is a device used to measure the voltage or potential difference between two points in a circuit. The video suggests using a voltmeter, which can be part of a multimeter, to measure the voltage across components like a battery or a lamp. The script emphasizes the importance of having a multimeter in one's toolkit for such measurements.

💡Alessandro Volta

Alessandro Volta is an Italian physicist mentioned in the video as the inventor of the voltaic pile, which was the first electrical battery capable of providing a steady electrical current in a circuit. The term 'volt,' the unit of measurement for voltage, is named in his honor, reflecting his significant contribution to the field of electricity and electrical engineering.

💡Parallel and Series Circuits

The video explains the concepts of parallel and series circuits to illustrate how voltage behaves in different configurations. In a series circuit, components are connected end-to-end, and the voltage adds up across each component, resulting in a higher total voltage. In contrast, in a parallel circuit, components are connected side-by-side, and the voltage remains the same across each component, but the current is divided among them.

💡Standardization of Voltage

The video discusses the historical context of voltage standardization, explaining that initially, there was no standard voltage or frequency for electrical distribution networks. Over time, as certain companies grew and dominated the market, voltage and frequency standards emerged. Governments also played a role in standardizing voltage to facilitate trade and ease the purchase of electrical products. The script highlights the differences in voltage standards around the world, such as 220-240 volts in most regions and 110-127 volts in North and Central America.

Highlights

Voltage is what pushes free electrons around a circuit, causing current.

Voltage can exist without current, similar to water pressure in a pipe with a closed valve.

Potential difference, or voltage, is the work that can potentially be done by a circuit.

A battery has a potential difference of 1.5 volts between its terminals.

Connecting electrical components in a circuit allows them to do work as electrons flow through them.

Adding batteries in series increases the voltage and pushing force, making a lamp glow brighter.

Connecting batteries in parallel splits the electron path, maintaining voltage but dimming the lamp.

Voltage is measured in volts, indicated by a 'V' on electrical appliances.

Voltage is the pressure that drives electrons, while volts are the units of measurement.

A voltmeter or multimeter can be used to measure voltage in a circuit.

One volt is the amount of pressure required to drive a specific number of electrons through a resistance.

Different voltages affect the brightness and functionality of devices like lamps.

Batteries provide direct voltage, moving electrons in a constant current in one direction.

Alternating voltage changes direction, like the tide, and is used in wall sockets.

Worldwide voltage standards vary due to historical distribution network differences.

Some devices can handle different voltages, indicated by the manufacturer's labels.

Mismatched voltages can damage devices or cause them to underperform.

Transcripts

Hey, there, guys.

Paul here from TheEngineeringMindset.com.

In this video, we're going to be discussing voltage.

We'll learn what is voltage and potential difference,

how to measure voltage, the difference between direct

and alternating voltage as well as current,

and finally, we'll briefly look at why

and how voltages vary around the world.

In our last video, we learned that electricity is the flow

of free electrons between atoms.

Voltage is what pushes the free electrons around a circuit.

Without voltage, the free electrons will move around

between atoms but they move around randomly,

so they aren't much use to us.

It's only when we apply a voltage to a circuit

that the free electrons will all move in the same direction,

causing current.

It's easy to imagine voltage like pressure in a water pipe.

If we have a water tank completely filled with water,

then the mass of all that water is going

to cause a huge amount of pressure at the end of the pipe.

If we have a water tank that's only partly filled,

then there will be much less pressure in the pipe.

If we open the valve to let the water flow,

then more water will flow at a faster rate

from the high-pressure tank compared

to the low-pressure tank.

The same with electricity; the more voltage we have,

then the more current can flow.

Voltage can exist without current.

For example, we can measure the pressure in the pipe

with the valve shut with no water flowing,

and from this, we can tell that the pipe is pressurized.

What we're really measuring is the pressure difference

between what's inside the pipe compared

to the pressure outside.

The same thing if we have a battery connected

to a circuit with an open switch.

The voltage is still present, we can measure that,

and as soon as the switch closes,

it's going to push the free electrons around the circuit.

We sometimes hear voltage referred

to as potential difference.

This really means how much work can potentially be done

by a circuit.

Coming back to our water analogy,

if we have two lakes at the same level,

then there is no potential to do work

because the water isn't flowing,

but if we raise one lake higher than the other,

then this higher lake now has the potential

to flow down to the second one,

and if we give it a path, then it will flow.

If we place a turbine in its path,

then we can use its energy to power a light

or even an entire town.

Back to the electrical circuit,

this battery has a potential difference

of 1.5 volts between its negative and positive terminal.

If we connect a piece of wire

to both terminals of a battery,

then the pressure of the battery will force electrons

to flow all in the same direction, along the same path.

We can then place electrical components in the path

of these electrons to do work for us.

For example, if we place a lamp into the circuit,

then this will light up as the electrons flow through it.

If we then added another battery to the circuit in series,

then the electrons will effectively be boosted

by my second battery because they can only flow

along this path, and there is more energy being added.

This will combine the voltages so we get 3 volts.

More volts equals more pressure,

which means more pushing force.

That will mean more electrons will flow

and the lamp will glow brighter.

However, if we were to move the battery

and connect it in parallel, then the path

of the electron splits.

Some will flow to the first battery

and some will flow to the second battery,

therefore, the batteries will both provide the same amount

of energy, so the voltage isn't combined,

the voltage isn't boosted, and we only get 1.5 volts.

So, the workload is split by the batteries

and the lamp will be powered for longer,

but it will be dimmer.

We've covered this in much more detail

within our Electrical Circuit series.

Do check that out, links are in the video description below.

We measure the potential difference of voltage

with the units of volts, and we use the symbol

of a capital V to show this.

If you look on your electrical appliances,

you will see a number next to a capital V,

indicating how many volts the product is designed for.

In this example, the manufacturers

of this USB hard drive are telling us

that the device needs to be connected

to a five-volt DC, or direct current supply

and it needs one amp of current for the device to work.

The term volt comes from an Italian physicist

named Alessandro Volta, who invented the voltaic pile,

which was the first electrical battery

that could provide an electrical current

in a steady rate in a circuit.

Voltage and volts are different.

Remember, voltage is the pressure

and volts is just the units we use to measure it in.

The same as we know the pipe has pressure

but we use units to measure this pressure,

such as bar, PSI, kPa, et cetera.

As we saw earlier, we can measure volts with a voltmeter.

This can be separate or part of a multimeter.

If you don't have a multimeter yet,

you can pick one of these up really cheaply.

I highly encourage you to have one in your tool kit.

I will leave a link in the video description down below

for where to get one for a good price.

To measure voltage, we have to connect

to the circuit in parallel across the two points

we would like to know the voltage,

or potential difference, for.

So, for a single battery in a circuit,

then we measure 1.5 volts across the battery

and we also measure 1.5 volts across the lamp.

The battery is providing providing 1.5 volts to the lamp,

and the lamp uses 1.5 volts to produce light and heat.

In a two-lamp series circuit,

we measure 1.5 volts across the battery,

1.5 volts across the two lamps combined,

but 0.75 volts across the lamps individually.

The voltage, or potential, has been shared between the lamps

to both provide light and heat.

The lamps are dimmer because the voltage has been shared

or divided.

Again, we'll cover this in more detail

in our Electrical Circuits Tutorials.

So, we saw earlier that voltage and volts are different.

Voltage is pressure and volts is the unit of measurement.

So, what does one volt mean?

One volt is required to drive one coulomb,

or approximately 6 quintillion, 242 quadrillion electrons,

through a resistance of one ohm in one second.

That's still a little confusing,

so another way to explain this is that,

to power this 1.5-watt lamp

with a 1.5-volt battery would require one coulomb,

or 6 quintillion,242 quadrillion electrons,

to flow from the battery and through the lamp every second

for it to stay on.

To power this 0.3-watt lamp

with a 1.5-volt battery would require 0.2 coulombs,

approx 1 quintillion,872 quadrillion,600 trillion electrons

to flow from the battery and through the lamp every second

for it to stay on.

If we try to use a lower voltage, the lamp would turn on

but it decreases in brightness as the voltage decreases.

That's because there is less pressure

to force electrons through it.

Less electrons flowing, less light that can be produced.

The lamps are only rated for a certain voltage and current.

If we use a higher voltage,

then the lamp will become brighter

because more electrons are flowing through it,

but if we add too much voltage and current,

then the lamp will blow because too many electrons tried

to pass through at once.

If we look at some typical batteries,

we can see that this AA battery has a voltage of 1.5 volts,

and this one has a voltage of 9 volts.

These are sources of direct voltage,

meaning, the pressure it provides moves the electrons

in a constant current in one direction,

much like the flow of water down a river.

We cover this in our last video on electricity basics,

so do check that out if you haven't already.

Links are in the video description below.

Direct voltage is usually represented with a capital V,

with some dots above this and a small horizontal line.

You can see an example of this on the multimeter

for the setting we would need

in order to measure the voltage in a DC supply.

If we plotted this voltage against time,

it would produce a straight line because it is constant;

it is direct in one direction.

The voltage in our wall sockets is alternating voltage.

This is a different type of electricity.

In this type, the electrons alternate

between flowing forwards and backwards

because the polarity of the circuit is changing,

much like the tide of the sea.

If we plotted this voltage against time,

we would get a sine wave as it moves forwards

and rises to its maximum and then starts to decline.

It passes through zero, and now the current

is flowing backwards but it then hits its minimum

and reverses direction again.

This is usually represented with a capital V

with a wave line above it.

You can see that on the multimeter here, also,

for measuring AC voltage.

The voltage at these sockets varies depending on

where in the world we are.

The majority of the world uses 220 to 240 volts,

but North, Central, and some of South America,

as well as a few countries

scattered across the planet will use 110 to 127 volts.

We can measure the voltage at our sockets

and see that it actually changes slightly throughout the day

as the demand on electricity network varies,

and we can do that using one of these cheap energy meters.

Again, links in the video description down below.

If you want one of these,

you can pick them up fairly cheaply,

and they're a great device for your toolbox.

The reason for different voltages around the world

goes all the way back to the beginning,

when electricity first started being distributed.

At first, there was no standardization,

so each distribution network had it's own voltage

and frequency for whatever their engineers felt was best.

Eventually, over time, some companies grew

and dominated the market, and so voltage

and frequency standardized as their products

and services expanded.

Governments also had to step in and pass laws

and regulations to help standardize their countries

so that people could buy products easily

but also trade products with other countries.

This is still a problem to this day,

but it's pretty much too late to fix,

as everyone is now so reliant on their electrical devices

and we would need to replace or modify them all

to solve the problem.

For example, if we take a hair dryer from the U.S.,

which is rated at 110 volts,

and we plug it into a wall socket in Europe,

which has 220 volts, the hairdryer will burn out

at full power because there is just simply too much voltage,

or too much pressure, and the device just can't cope.

If we took a hair dryer from Europe

and plugged it into a U.S. socket,

it probably won't turn on, but if it does,

it's not going to be very strong; it's gonna be pretty weak

because there just isn't enough pressure for it to function.

Some products can be used in different voltages, though.

You need to check the manufacturer's labels on the product

to first see if the product has been designed

to cope with different voltages.

For example, this laptop charger shows

that it can be used on voltages between 100 and 240 volts,

whereas this charger is only rated

for 220 volts or 240 volts.

Okay, guys, that's it for this video,

but if you want to continue your learning

with your electrical engineering,

then check out these videos here

and I'll catch you there for the next lesson.

Leave your questions in the Comment section down below,

and don't forget to follow us on Facebook,

Instagram, Twitter, as well as TheEngineeringMindset.com.

Once again, thanks for watching.