First we connect only one cell in the circuit and take the ammeter and voltmeter readings

Tabulate the values on the table now connect two cells and take ammeter voltmeter readings

Tabulate the values in the table repeat this experiment with 3 and 4 cells and take readings of ammeter and voltmeter

Procedure: connect ammeter nichrome wire cell and plug key in series and voltmeter in parallel

We can observe that the given line passing through the origin and we can say that V/I ratio is constant

Tabulate the values on the table now connect two cells and take ammeter voltmeter readings

Tabulate the values in the table repeat this experiment with 3 and 4 cells and take readings of ammeter and voltmeter

Procedure: connect ammeter nichrome wire cell and plug key in series and voltmeter in parallel

Tabulate values in the table plot a graph between V and I take current on x-axis and potential difference on y-axis from the graph

We can observe that the given line passing through the origin and we can say that V/I ratio is constant

This experiment was practically observed by George Simon Ohm in 1827 according to this potential difference V across the ends of wire in the circuit, V is directly proportional to current I flowing through it at constant temperature

Tabulate the values in the table repeat this experiment with 3 and 4 cells and take readings of ammeter and voltmeter

Procedure: connect ammeter nichrome wire cell and plug key in series and voltmeter in parallel

Tabulate values in the table plot a graph between V and I take current on x-axis and potential difference on y-axis from the graph

We can observe that the given line passing through the origin and we can say that V/I ratio is constant

This experiment was practically observed by George Simon Ohm in 1827 according to this potential difference V across the ends of wire in the circuit, V is directly proportional to current I flowing through it at constant temperature

This is called Ohm's Law from this we get that V/I is equal to constant

Procedure: connect ammeter nichrome wire cell and plug key in series and voltmeter in parallel

Tabulate values in the table plot a graph between V and I take current on x-axis and potential difference on y-axis from the graph

We can observe that the given line passing through the origin and we can say that V/I ratio is constant

This experiment was practically observed by George Simon Ohm in 1827 according to this potential difference V across the ends of wire in the circuit, V is directly proportional to current I flowing through it at constant temperature

This is called Ohm's Law from this we get that V/I is equal to constant

That is V/I is equal to R or V is equal to I R

Tabulate values in the table plot a graph between V and I take current on x-axis and potential difference on y-axis from the graph

We can observe that the given line passing through the origin and we can say that V/I ratio is constant

This experiment was practically observed by George Simon Ohm in 1827 according to this potential difference V across the ends of wire in the circuit, V is directly proportional to current I flowing through it at constant temperature

This is called Ohm's Law from this we get that V/I is equal to constant

That is V/I is equal to R or V is equal to I R

Here, the constant R is called resistance

It is the property of a conductor to resist the flow of charges through it

This experiment was practically observed by George Simon Ohm in 1827 according to this potential difference V across the ends of wire in the circuit, V is directly proportional to current I flowing through it at constant temperature

This is called Ohm's Law from this we get that V/I is equal to constant

That is V/I is equal to R or V is equal to I R

Here, the constant R is called resistance

It is the property of a conductor to resist the flow of charges through it

SI unit is Ohm it is represented by Ω = Greek letter omega

This is called Ohm's Law from this we get that V/I is equal to constant

That is V/I is equal to R or V is equal to I R

Here, the constant R is called resistance

It is the property of a conductor to resist the flow of charges through it

SI unit is Ohm it is represented by Ω = Greek letter omega

According to Ohm's law, R is equal to V/ I

That is V/I is equal to R or V is equal to I R

Here, the constant R is called resistance

It is the property of a conductor to resist the flow of charges through it

SI unit is Ohm it is represented by Ω = Greek letter omega

According to Ohm's law, R is equal to V/ I

If the potential difference across the two ends of the conductor is 1 volt and current through it is 1 ampere then the resistance R of the conductor is 1 Ohm

Here, the constant R is called resistance

It is the property of a conductor to resist the flow of charges through it

SI unit is Ohm it is represented by Ω = Greek letter omega

According to Ohm's law, R is equal to V/ I

If the potential difference across the two ends of the conductor is 1 volt and current through it is 1 ampere then the resistance R of the conductor is 1 Ohm

That is 1 ohm is equal to 1 volt/ 1 ampere from Ohm's law

I equals 2 we by arm we can say that current is inversely proportional to resistance R

SI unit is Ohm it is represented by Ω = Greek letter omega

According to Ohm's law, R is equal to V/ I

If the potential difference across the two ends of the conductor is 1 volt and current through it is 1 ampere then the resistance R of the conductor is 1 Ohm

That is 1 ohm is equal to 1 volt/ 1 ampere from Ohm's law

I equals 2 we by arm we can say that current is inversely proportional to resistance R

SI unit is Ohm it is represented by Ω = Greek letter omega

According to Ohm's law, R is equal to V/ I

If the potential difference across the two ends of the conductor is 1 volt and current through it is 1 ampere then the resistance R of the conductor is 1 Ohm

That is 1 ohm is equal to 1 volt/ 1 ampere from Ohm's law

I equals 2 we by arm we can say that current is inversely proportional to resistance R

SI unit is Ohm it is represented by Ω = Greek letter omega

According to Ohm's law, R is equal to V/ I

If the potential difference across the two ends of the conductor is 1 volt and current through it is 1 ampere then the resistance R of the conductor is 1 Ohm

That is 1 ohm is equal to 1 volt/ 1 ampere from Ohm's law

I equals 2 we by arm we can say that current is inversely proportional to resistance R

SI unit is Ohm it is represented by Ω = Greek letter omega

According to Ohm's law, R is equal to V/ I

If the potential difference across the two ends of the conductor is 1 volt and current through it is 1 ampere then the resistance R of the conductor is 1 Ohm

That is 1 ohm is equal to 1 volt/ 1 ampere from Ohm's law

I equals 2 we by arm we can say that current is inversely proportional to resistance R

SI unit is Ohm it is represented by Ω = Greek letter omega

According to Ohm's law, R is equal to V/ I

If the potential difference across the two ends of the conductor is 1 volt and current through it is 1 ampere then the resistance R of the conductor is 1 Ohm

That is 1 ohm is equal to 1 volt/ 1 ampere from Ohm's law

In this video I'm going to talk about electrical resistance, ohm's law, and how to pick a resistor to limit current in an LED circuit.

In previous videos I talked about how voltage can behave like a pushing force, pushing electric current around a circuit.

But in one example I connected an LED straight to 7.5V, way too much current flowed, and the LED blew up.

So you can see how it would be useful if there was something that could resist the flow of electrical current

Something that could tame the flow in a controlled way.

That device is called a resistor, and here are some examples of what resistors can look like.

In previous videos I talked about how voltage can behave like a pushing force, pushing electric current around a circuit.

But in one example I connected an LED straight to 7.5V, way too much current flowed, and the LED blew up.

So you can see how it would be useful if there was something that could resist the flow of electrical current

Something that could tame the flow in a controlled way.

That device is called a resistor, and here are some examples of what resistors can look like.

We've got a very basic resistor over here, which is the

kind of resistor that most hobbyists would use at home when constructing circuits.

But in one example I connected an LED straight to 7.5V, way too much current flowed, and the LED blew up.

So you can see how it would be useful if there was something that could resist the flow of electrical current

Something that could tame the flow in a controlled way.

That device is called a resistor, and here are some examples of what resistors can look like.

We've got a very basic resistor over here, which is the

kind of resistor that most hobbyists would use at home when constructing circuits.

And over here we have a tiny surface mount resistor.

So you can see how it would be useful if there was something that could resist the flow of electrical current

Something that could tame the flow in a controlled way.

That device is called a resistor, and here are some examples of what resistors can look like.

We've got a very basic resistor over here, which is the

kind of resistor that most hobbyists would use at home when constructing circuits.

And over here we have a tiny surface mount resistor.

This is something you'd expect to see in a small device like your phone.

Something that could tame the flow in a controlled way.

That device is called a resistor, and here are some examples of what resistors can look like.

We've got a very basic resistor over here, which is the

kind of resistor that most hobbyists would use at home when constructing circuits.

And over here we have a tiny surface mount resistor.

This is something you'd expect to see in a small device like your phone.

And this big resistor is the type of thing you'd use large power

supply.

So how do these resistors work?

We've got a very basic resistor over here, which is the

kind of resistor that most hobbyists would use at home when constructing circuits.

And over here we have a tiny surface mount resistor.

This is something you'd expect to see in a small device like your phone.

And this big resistor is the type of thing you'd use large power

supply.

So how do these resistors work?

Remember how in my video about current, I talked about electrons jumping from atom to atom, all at the same time, like a conga line?

And over here we have a tiny surface mount resistor.

This is something you'd expect to see in a small device like your phone.

And this big resistor is the type of thing you'd use large power

supply.

So how do these resistors work?

Remember how in my video about current, I talked about electrons jumping from atom to atom, all at the same time, like a conga line?

The atoms in a material like copper wire are always vibrating around just a little bit, and this is because of the heat energy they have.

This is something you'd expect to see in a small device like your phone.

And this big resistor is the type of thing you'd use large power

supply.

So how do these resistors work?

Remember how in my video about current, I talked about electrons jumping from atom to atom, all at the same time, like a conga line?

The atoms in a material like copper wire are always vibrating around just a little bit, and this is because of the heat energy they have.

When electrons try to move through the wire, sometimes they'll bump into an atom that's in the way, and effectively the flow of current gets resisted.

And this big resistor is the type of thing you'd use large power

supply.

So how do these resistors work?

Remember how in my video about current, I talked about electrons jumping from atom to atom, all at the same time, like a conga line?

The atoms in a material like copper wire are always vibrating around just a little bit, and this is because of the heat energy they have.

When electrons try to move through the wire, sometimes they'll bump into an atom that's in the way, and effectively the flow of current gets resisted.

As this happens, some of the kinetic or movement energy

from the electrons gets converted into heat.

So how do these resistors work?

Remember how in my video about current, I talked about electrons jumping from atom to atom, all at the same time, like a conga line?

The atoms in a material like copper wire are always vibrating around just a little bit, and this is because of the heat energy they have.

When electrons try to move through the wire, sometimes they'll bump into an atom that's in the way, and effectively the flow of current gets resisted.

As this happens, some of the kinetic or movement energy

from the electrons gets converted into heat.

This is the fundamental principle behind how electric heaters

and incandescent light bulbs work.

Remember how in my video about current, I talked about electrons jumping from atom to atom, all at the same time, like a conga line?

The atoms in a material like copper wire are always vibrating around just a little bit, and this is because of the heat energy they have.

When electrons try to move through the wire, sometimes they'll bump into an atom that's in the way, and effectively the flow of current gets resisted.

As this happens, some of the kinetic or movement energy

from the electrons gets converted into heat.

This is the fundamental principle behind how electric heaters

and incandescent light bulbs work.

But it's not just metals that have the property of resistance, resistance can exist simply from the fact that some materials just don't have a suitable arrangement of atoms for electrons to flow through.

The atoms in a material like copper wire are always vibrating around just a little bit, and this is because of the heat energy they have.

When electrons try to move through the wire, sometimes they'll bump into an atom that's in the way, and effectively the flow of current gets resisted.

As this happens, some of the kinetic or movement energy

from the electrons gets converted into heat.

This is the fundamental principle behind how electric heaters

and incandescent light bulbs work.

But it's not just metals that have the property of resistance, resistance can exist simply from the fact that some materials just don't have a suitable arrangement of atoms for electrons to flow through.

And some materials just don't have enough free electrons floating around for large amounts of current to flow.

When electrons try to move through the wire, sometimes they'll bump into an atom that's in the way, and effectively the flow of current gets resisted.

As this happens, some of the kinetic or movement energy

from the electrons gets converted into heat.

This is the fundamental principle behind how electric heaters

and incandescent light bulbs work.

But it's not just metals that have the property of resistance, resistance can exist simply from the fact that some materials just don't have a suitable arrangement of atoms for electrons to flow through.

And some materials just don't have enough free electrons floating around for large amounts of current to flow.

Keep in mind this is a huge simplification and this is not how actual atoms and electrons are going to look and behave at the subatomic level.

As this happens, some of the kinetic or movement energy

from the electrons gets converted into heat.

This is the fundamental principle behind how electric heaters

and incandescent light bulbs work.

But it's not just metals that have the property of resistance, resistance can exist simply from the fact that some materials just don't have a suitable arrangement of atoms for electrons to flow through.

And some materials just don't have enough free electrons floating around for large amounts of current to flow.

Keep in mind this is a huge simplification and this is not how actual atoms and electrons are going to look and behave at the subatomic level.

Nearly everything on earth has some resistance to electrical current, and metals tend to have the least resistance.

Sorry, I had to put it in the video somewhere. We measure the amount of resistance with a unit called ohms. The symbol is the Greek Letter Omega Ω.

But it's not just metals that have the property of resistance, resistance can exist simply from the fact that some materials just don't have a suitable arrangement of atoms for electrons to flow through.

And some materials just don't have enough free electrons floating around for large amounts of current to flow.

Keep in mind this is a huge simplification and this is not how actual atoms and electrons are going to look and behave at the subatomic level.

Nearly everything on earth has some resistance to electrical current, and metals tend to have the least resistance.

Sorry, I had to put it in the video somewhere. We measure the amount of resistance with a unit called ohms. The symbol is the Greek Letter Omega Ω.

To give you a sense of scale, a resistance of under 1 ohm is considered to be a very low resistance.

And some materials just don't have enough free electrons floating around for large amounts of current to flow.

Keep in mind this is a huge simplification and this is not how actual atoms and electrons are going to look and behave at the subatomic level.

Nearly everything on earth has some resistance to electrical current, and metals tend to have the least resistance.

Sorry, I had to put it in the video somewhere. We measure the amount of resistance with a unit called ohms. The symbol is the Greek Letter Omega Ω.

To give you a sense of scale, a resistance of under 1 ohm is considered to be a very low resistance.

That's something that you'd expect to see from a piece of wire that's good at conducting electricity. 1 million ohms, or 1 megaohm, is generally considered to be a very high resistance.

Keep in mind this is a huge simplification and this is not how actual atoms and electrons are going to look and behave at the subatomic level.

Nearly everything on earth has some resistance to electrical current, and metals tend to have the least resistance.

Sorry, I had to put it in the video somewhere. We measure the amount of resistance with a unit called ohms. The symbol is the Greek Letter Omega Ω.

To give you a sense of scale, a resistance of under 1 ohm is considered to be a very low resistance.

That's something that you'd expect to see from a piece of wire that's good at conducting electricity. 1 million ohms, or 1 megaohm, is generally considered to be a very high resistance.

That's something that you'd expect to see from a piece of wire that's good at conducting electricity.

1 million ohms, or 1 megaohm, is generally considered to be a very high resistance.

Nearly everything on earth has some resistance to electrical current, and metals tend to have the least resistance.

Sorry, I had to put it in the video somewhere. We measure the amount of resistance with a unit called ohms. The symbol is the Greek Letter Omega Ω.

To give you a sense of scale, a resistance of under 1 ohm is considered to be a very low resistance.

That's something that you'd expect to see from a piece of wire that's good at conducting electricity. 1 million ohms, or 1 megaohm, is generally considered to be a very high resistance.

That's something that you'd expect to see from a piece of wire that's good at conducting electricity.

1 million ohms, or 1 megaohm, is generally considered to be a very high resistance.

That's something that you might expect to see from a bad conductor of electricity like this dried out piece of carrot.

This thing that I am using to measure resistance is called a multimeter, and it can measure the resistance of almost anything.

To give you a sense of scale, a resistance of under 1 ohm is considered to be a very low resistance.

That's something that you'd expect to see from a piece of wire that's good at conducting electricity. 1 million ohms, or 1 megaohm, is generally considered to be a very high resistance.

That's something that you'd expect to see from a piece of wire that's good at conducting electricity.

1 million ohms, or 1 megaohm, is generally considered to be a very high resistance.

That's something that you might expect to see from a bad conductor of electricity like this dried out piece of carrot.

This thing that I am using to measure resistance is called a multimeter, and it can measure the resistance of almost anything.

I have a separate tutorial on multimeters, and I recommend you watch it as soon as possible to learn more about this important tool.

That's something that you'd expect to see from a piece of wire that's good at conducting electricity. 1 million ohms, or 1 megaohm, is generally considered to be a very high resistance.

That's something that you'd expect to see from a piece of wire that's good at conducting electricity.

1 million ohms, or 1 megaohm, is generally considered to be a very high resistance.

That's something that you might expect to see from a bad conductor of electricity like this dried out piece of carrot.

This thing that I am using to measure resistance is called a multimeter, and it can measure the resistance of almost anything.

I have a separate tutorial on multimeters, and I recommend you watch it as soon as possible to learn more about this important tool.

Now if you're playing with electronics at home, you'll be using resistors that look like these.

That's something that you'd expect to see from a piece of wire that's good at conducting electricity.

1 million ohms, or 1 megaohm, is generally considered to be a very high resistance.

That's something that you might expect to see from a bad conductor of electricity like this dried out piece of carrot.

This thing that I am using to measure resistance is called a multimeter, and it can measure the resistance of almost anything.

I have a separate tutorial on multimeters, and I recommend you watch it as soon as possible to learn more about this important tool.

Now if you're playing with electronics at home, you'll be using resistors that look like these.

They have colored bands on them, and there's a special code that lets you translate the colors into a resistance value.

That's something that you might expect to see from a bad conductor of electricity like this dried out piece of carrot.

This thing that I am using to measure resistance is called a multimeter, and it can measure the resistance of almost anything.

I have a separate tutorial on multimeters, and I recommend you watch it as soon as possible to learn more about this important tool.

Now if you're playing with electronics at home, you'll be using resistors that look like these.

They have colored bands on them, and there's a special code that lets you translate the colors into a resistance value.

For example these red, violet, brown and gold bands mean this is a 270 ohm resistor.

Now you can memorize the color code, but it's a lot easier to just use one of the many resistor calculators out there.

I have a separate tutorial on multimeters, and I recommend you watch it as soon as possible to learn more about this important tool.

Now if you're playing with electronics at home, you'll be using resistors that look like these.

They have colored bands on them, and there's a special code that lets you translate the colors into a resistance value.

For example these red, violet, brown and gold bands mean this is a 270 ohm resistor.

Now you can memorize the color code, but it's a lot easier to just use one of the many resistor calculators out there.

Just search for resistor color calculator on Google or in your phone's app store.

Now if you're playing with electronics at home, you'll be using resistors that look like these.

They have colored bands on them, and there's a special code that lets you translate the colors into a resistance value.

For example these red, violet, brown and gold bands mean this is a 270 ohm resistor.

Now you can memorize the color code, but it's a lot easier to just use one of the many resistor calculators out there.

Just search for resistor color calculator on Google or in your phone's app store.

Just search for resistor color calculator on Google or in your phone's app store.

They have colored bands on them, and there's a special code that lets you translate the colors into a resistance value.

For example these red, violet, brown and gold bands mean this is a 270 ohm resistor.

Now you can memorize the color code, but it's a lot easier to just use one of the many resistor calculators out there.

Just search for resistor color calculator on Google or in your phone's app store.

Just search for resistor color calculator on Google or in your phone's app store.

By having resistors with specific resistance values we can carefully control the amount of current that flows in a circuit.

For example these red, violet, brown and gold bands mean this is a 270 ohm resistor.

Now you can memorize the color code, but it's a lot easier to just use one of the many resistor calculators out there.

Just search for resistor color calculator on Google or in your phone's app store.

Just search for resistor color calculator on Google or in your phone's app store.

By having resistors with specific resistance values we can carefully control the amount of current that flows in a circuit.

Today, let's start out with everyone's first simple resistor circuit, using a resistor to limit the current going through an LED.

Make sure you've already watched my LED tutorial and have bought some LEDs and resistors, which I am going to link again in the video description section.

Just search for resistor color calculator on Google or in your phone's app store.

Just search for resistor color calculator on Google or in your phone's app store.

By having resistors with specific resistance values we can carefully control the amount of current that flows in a circuit.

Today, let's start out with everyone's first simple resistor circuit, using a resistor to limit the current going through an LED.

Make sure you've already watched my LED tutorial and have bought some LEDs and resistors, which I am going to link again in the video description section.

In order to do the math for this circuit you need to know about the mathematical relationship between voltage, current and resistance.

Just search for resistor color calculator on Google or in your phone's app store.

By having resistors with specific resistance values we can carefully control the amount of current that flows in a circuit.

Today, let's start out with everyone's first simple resistor circuit, using a resistor to limit the current going through an LED.

Make sure you've already watched my LED tutorial and have bought some LEDs and resistors, which I am going to link again in the video description section.

In order to do the math for this circuit you need to know about the mathematical relationship between voltage, current and resistance.

Here's an old comic that I've always liked that illustrates the relationship on an intuitive level.

By having resistors with specific resistance values we can carefully control the amount of current that flows in a circuit.

Today, let's start out with everyone's first simple resistor circuit, using a resistor to limit the current going through an LED.

Make sure you've already watched my LED tutorial and have bought some LEDs and resistors, which I am going to link again in the video description section.

In order to do the math for this circuit you need to know about the mathematical relationship between voltage, current and resistance.

Here's an old comic that I've always liked that illustrates the relationship on an intuitive level.

More formally, we use this equation. Ohm's law.

Today, let's start out with everyone's first simple resistor circuit, using a resistor to limit the current going through an LED.

Make sure you've already watched my LED tutorial and have bought some LEDs and resistors, which I am going to link again in the video description section.

In order to do the math for this circuit you need to know about the mathematical relationship between voltage, current and resistance.

Here's an old comic that I've always liked that illustrates the relationship on an intuitive level.

More formally, we use this equation. Ohm's law.

In textbooks you usually see it written as V=I x R. Or voltage = current times resistance.

If you use a little algebra you can rearrange the equation to calculate any of the variables as long as you know the other two.

In order to do the math for this circuit you need to know about the mathematical relationship between voltage, current and resistance.

Here's an old comic that I've always liked that illustrates the relationship on an intuitive level.

More formally, we use this equation. Ohm's law.

In textbooks you usually see it written as V=I x R. Or voltage = current times resistance.

If you use a little algebra you can rearrange the equation to calculate any of the variables as long as you know the other two.

Although it's important to understand that all these versions of the equation are exactly the same thing, our LED circuit is going to be using this version, so let's focus on that.

Here's an old comic that I've always liked that illustrates the relationship on an intuitive level.

More formally, we use this equation. Ohm's law.

In textbooks you usually see it written as V=I x R. Or voltage = current times resistance.

If you use a little algebra you can rearrange the equation to calculate any of the variables as long as you know the other two.

Although it's important to understand that all these versions of the equation are exactly the same thing, our LED circuit is going to be using this version, so let's focus on that.

Let's say we have a 10 volt power source, and we want to make sure that no more than 10mA flows from it.

More formally, we use this equation. Ohm's law.

In textbooks you usually see it written as V=I x R. Or voltage = current times resistance.

If you use a little algebra you can rearrange the equation to calculate any of the variables as long as you know the other two.

Although it's important to understand that all these versions of the equation are exactly the same thing, our LED circuit is going to be using this version, so let's focus on that.

Let's say we have a 10 volt power source, and we want to make sure that no more than 10mA flows from it.

We can use ohm's law to figure out what resistor will accomplish this.

In textbooks you usually see it written as V=I x R. Or voltage = current times resistance.

If you use a little algebra you can rearrange the equation to calculate any of the variables as long as you know the other two.

Although it's important to understand that all these versions of the equation are exactly the same thing, our LED circuit is going to be using this version, so let's focus on that.

Let's say we have a 10 volt power source, and we want to make sure that no more than 10mA flows from it.

We can use ohm's law to figure out what resistor will accomplish this.

The answer is really simple, just take the voltage, divide it by the desired current, and we get the answer of 1000 Ohms.

So now we can either use the resistor color code, or a resistor calculator app to figure out what a 1000 ohm resistor looks like, and it turns out to be brown, black, red.

Although it's important to understand that all these versions of the equation are exactly the same thing, our LED circuit is going to be using this version, so let's focus on that.

Let's say we have a 10 volt power source, and we want to make sure that no more than 10mA flows from it.

We can use ohm's law to figure out what resistor will accomplish this.

The answer is really simple, just take the voltage, divide it by the desired current, and we get the answer of 1000 Ohms.

So now we can either use the resistor color code, or a resistor calculator app to figure out what a 1000 ohm resistor looks like, and it turns out to be brown, black, red.

The 4th color band all the way on the right refers to the tolerance of the resistor.

Let's say we have a 10-volt power source, and we want to make sure that no more than 10mA flows from it.

We can use ohm's law to figure out what resistor will accomplish this.

The answer is really simple, just take the voltage, divide it by the desired current, and we get the answer of 1000 Ohms.

So now we can either use the resistor color code, or a resistor calculator app to figure out what a 1000 ohm resistor looks like, and it turns out to be brown, black, red.

The 4th color band all the way on the right refers to the tolerance of the resistor.

A real world 1000 ohm resistor might actually have a resistance of 1020 ohms, or 998 ohms, and for most circuits you play with at home +/-

We can use ohm's law to figure out what resistor will accomplish this.

The answer is really simple, just take the voltage, divide it by the desired current, and we get the answer of 1000 Ohms.

So now we can either use the resistor color code, or a resistor calculator app to figure out what a 1000 ohm resistor looks like, and it turns out to be brown, black, red.

The 4th color band all the way on the right refers to the tolerance of the resistor.

A real world 1000 ohm resistor might actually have a resistance of 1020 ohms, or 998 ohms, and for most circuits you play with at home +/-

5% will be good enough. So let's double check our math in real life.

The answer is really simple, just take the voltage, divide it by the desired current, and we get the answer of 1000 Ohms.

So now we can either use the resistor color code, or a resistor calculator app to figure out what a 1000 ohm resistor looks like, and it turns out to be brown, black, red.

The 4th color band all the way on the right refers to the tolerance of the resistor.

A real world 1000 ohm resistor might actually have a resistance of 1020 ohms, or 998 ohms, and for most circuits you play with at home +/-

5% will be good enough. So let's double check our math in real life.

I've got my power supply set to 10 volts, it's hooked up to a 1k resistor, and as you'd expect, 10mA is flowing from the power supply.

It's also important to know that ohm's law is a linear relationship, meaning that for a fixed resistor value, if you double the voltage, you double the current.

The 4th color band all the way on the right refers to the tolerance of the resistor.

A real world 1000 ohm resistor might actually have a resistance of 1020 ohms, or 998 ohms, and for most circuits you play with at home +/-

5% will be good enough. So let's double check our math in real life.

I've got my power supply set to 10 volts, it's hooked up to a 1k resistor, and as you'd expect, 10mA is flowing from the power supply.

It's also important to know that ohm's law is a linear relationship, meaning that for a fixed resistor value, if you double the voltage, you double the current.

Here's 20 volts going into the same 1000 ohm resistor, and as you'd expect, the current doubles to 20mA.

A real world 1000 ohm resistor might actually have a resistance of 1020 ohms, or 998 ohms, and for most circuits you play with at home +/-

5% will be good enough. So let's double check our math in real life.

I've got my power supply set to 10 volts, it's hooked up to a 1k resistor, and as you'd expect, 10mA is flowing from the power supply.

It's also important to know that ohm's law is a linear relationship, meaning that for a fixed resistor value, if you double the voltage, you double the current.

Here's 20 volts going into the same 1000 ohm resistor, and as you'd expect, the current doubles to 20mA.

I want you to understand that only pure simple resistors obey Ohm's law.

5% will be good enough. So let's double check our math in real life.

I've got my power supply set to 10 volts, it's hooked up to a 1k resistor, and as you'd expect, 10mA is flowing from the power supply.

It's also important to know that ohm's law is a linear relationship, meaning that for a fixed resistor value, if you double the voltage, you double the current.

Here's 20 volts going into the same 1000 ohm resistor, and as you'd expect, the current doubles to 20mA.

I want you to understand that only pure simple resistors obey Ohm's law.

The relationship between voltage and current for most electronics is a lot more complicated than this.

I've got my power supply set to 10 volts, it's hooked up to a 1k resistor, and as you'd expect, 10mA is flowing from the power supply.

It's also important to know that ohm's law is a linear relationship, meaning that for a fixed resistor value, if you double the voltage, you double the current.

Here's 20 volts going into the same 1000 ohm resistor, and as you'd expect, the current doubles to 20mA.

I want you to understand that only pure simple resistors obey Ohm's law.

The relationship between voltage and current for most electronics is a lot more complicated than this.

In a lot of cases things will work fine up until their recommended voltage level, and if you exceed that then things suddenly blow up.

But for now, resistors are good enough to help us limit current in a simple LED circuit.

Here's 20 volts going into the same 1000 ohm resistor, and as you'd expect, the current doubles to 20mA.

I want you to understand that only pure simple resistors obey Ohm's law.

The relationship between voltage and current for most electronics is a lot more complicated than this.

In a lot of cases things will work fine up until their recommended voltage level, and if you exceed that then things suddenly blow up.

But for now, resistors are good enough to help us limit current in a simple LED circuit.

Let's start out with a 9 volt battery, a resistor, and an LED connected with the correct polarity.

I want you to understand that only pure simple resistors obey Ohm's law.

The relationship between voltage and current for most electronics is a lot more complicated than this.

In a lot of cases things will work fine up until their recommended voltage level, and if you exceed that then things suddenly blow up.

But for now, resistors are good enough to help us limit current in a simple LED circuit.

Let's start out with a 9 volt battery, a resistor, and an LED connected with the correct polarity.

And notice that it doesn't matter which way we connect the resistor - unlike the LED, polarity doesn't matter for resistors.

The relationship between voltage and current for most electronics is a lot more complicated than this.

In a lot of cases things will work fine up until their recommended voltage level, and if you exceed that then things suddenly blow up.

But for now, resistors are good enough to help us limit current in a simple LED circuit.

Let's start out with a 9 volt battery, a resistor, and an LED connected with the correct polarity.

And notice that it doesn't matter which way we connect the resistor - unlike the LED, polarity doesn't matter for resistors.

We want to find out what resistor will let us safely use 9 volts with this LED.

In a lot of cases things will work fine up until their recommended voltage level, and if you exceed that then things suddenly blow up.

But for now, resistors are good enough to help us limit current in a simple LED circuit.

Let's start out with a 9 volt battery, a resistor, and an LED connected with the correct polarity.

And notice that it doesn't matter which way we connect the resistor - unlike the LED, polarity doesn't matter for resistors.

We want to find out what resistor will let us safely use 9 volts with this LED.

In my previous video about LEDs we talked about forward voltages, and for this particular white LED the forward voltage is 3 volts.

That means that when the LED is on, there is going to be a 3 volt drop across it.

Let's start out with a 9 volt battery, a resistor, and an LED connected with the correct polarity.

And notice that it doesn't matter which way we connect the resistor - unlike the LED, polarity doesn't matter for resistors.

We want to find out what resistor will let us safely use 9 volts with this LED.

In my previous video about LEDs we talked about forward voltages, and for this particular white LED the forward voltage is 3 volts.

That means that when the LED is on, there is going to be a 3 volt drop across it.

So... what is the voltage across the resistor?

Remember that voltage is all about differences in electrical potential between two points.

And notice that it doesn't matter which way we connect the resistor - unlike the LED, polarity doesn't matter for resistors.

We want to find out what resistor will let us safely use 9 volts with this LED.

In my previous video about LEDs we talked about forward voltages, and for this particular white LED the forward voltage is 3 volts.

That means that when the LED is on, there is going to be a 3 volt drop across it.

So... what is the voltage across the resistor?

Remember that voltage is all about differences in electrical potential between two points.

Our power source is a 9 volt battery, so we've got 9 volts between here and here, and we've got 3 volts across the LED.

We want to find out what resistor will let us safely use 9 volts with this LED.

In my previous video about LEDs we talked about forward voltages, and for this particular white LED the forward voltage is 3 volts.

That means that when the LED is on, there is going to be a 3 volt drop across it.

So... what is the voltage across the resistor?

Remember that voltage is all about differences in electrical potential between two points.

Our power source is a 9 volt battery, so we've got 9 volts between here and here, and we've got 3 volts across the LED.

So this must mean that we've got 6 volts across this resistor, because 9 - 3 is 6. Ok so we've got our voltage.

In my previous video about LEDs we talked about forward voltages, and for this particular white LED the forward voltage is 3 volts.

That means that when the LED is on, there is going to be a 3 volt drop across it.

So... what is the voltage across the resistor?

Remember that voltage is all about differences in electrical potential between two points.

Our power source is a 9 volt battery, so we've got 9 volts between here and here, and we've got 3 volts across the LED.

So this must mean that we've got 6 volts across this resistor, because 9 - 3 is 6. Ok so we've got our voltage.

Now the current in this circuit is going to be whatever we want to it to be.

But the recommended maximum current for this LED is 20mA, so we're going to use that.

So... what is the voltage across the resistor?

Remember that voltage is all about differences in electrical potential between two points.

Our power source is a 9 volt battery, so we've got 9 volts between here and here, and we've got 3 volts across the LED.

So this must mean that we've got 6 volts across this resistor, because 9 - 3 is 6. Ok so we've got our voltage.

Now the current in this circuit is going to be whatever we want to it to be.

But the recommended maximum current for this LED is 20mA, so we're going to use that.

And notice that I am using conventional current here which moves from positive to negative.

Our power source is a 9 volt battery, so we've got 9 volts between here and here, and we've got 3 volts across the LED.

So this must mean that we've got 6 volts across this resistor, because 9 - 3 is 6. Ok so we've got our voltage.

Now the current in this circuit is going to be whatever we want to it to be.

But the recommended maximum current for this LED is 20mA, so we're going to use that.

And notice that I am using conventional current here which moves from positive to negative.

That's what you are going to see in every single electrical engineering situation, theoretical physics classes might use negative to positive electron flow.

So this must mean that we've got 6 volts across this resistor, because 9 - 3 is 6. Ok so we've got our voltage.

Now the current in this circuit is going to be whatever we want to it to be.

But the recommended maximum current for this LED is 20mA, so we're going to use that.

And notice that I am using conventional current here which moves from positive to negative.

That's what you are going to see in every single electrical engineering situation, theoretical physics classes might use negative to positive electron flow.

So let's apply Ohm's law now. 6 volts divided by 20mA gives us a resistance value of 300 ohms.

Now the current in this circuit is going to be whatever we want to it to be.

But the recommended maximum current for this LED is 20mA, so we're going to use that.

And notice that I am using conventional current here which moves from positive to negative.

That's what you are going to see in every single electrical engineering situation, theoretical physics classes might use negative to positive electron flow.

So let's apply Ohm's law now. 6 volts divided by 20mA gives us a resistance value of 300 ohms.

Now I don't have a 300 ohm resistor in my parts collection, but a 330 ohm resistor will be good enough.

If you are messing around with LEDs at home it doesn't matter if you get the current wrong by 10%. Ok, so here I have my 9 volt battery and a 9 volt battery clip.

And notice that I am using conventional current here which moves from positive to negative.

That's what you are going to see in every single electrical engineering situation, theoretical physics classes might use negative to positive electron flow.

So let's apply Ohm's law now. 6 volts divided by 20mA gives us a resistance value of 300 ohms.

Now I don't have a 300 ohm resistor in my parts collection, but a 330 ohm resistor will be good enough.

If you are messing around with LEDs at home it doesn't matter if you get the current wrong by 10%. Ok, so here I have my 9 volt battery and a 9 volt battery clip.

The red positive wire is going to one side of my 330 ohm resistor, and that's going to the LED's anode.

That's what you are going to see in every single electrical engineering situation, theoretical physics classes might use negative to positive electron flow.

So let's apply Ohm's law now. 6 volts divided by 20mA gives us a resistance value of 300 ohms.

Now I don't have a 300 ohm resistor in my parts collection, but a 330 ohm resistor will be good enough.

If you are messing around with LEDs at home it doesn't matter if you get the current wrong by 10%. Ok, so here I have my 9 volt battery and a 9 volt battery clip.

The red positive wire is going to one side of my 330 ohm resistor, and that's going to the LED's anode.

Then I'm just connecting the negative wire from my battery to the LED's cathode.

So let's apply Ohm's law now. 6 volts divided by 20mA gives us a resistance value of 300 ohms.

Now I don't have a 300 ohm resistor in my parts collection, but a 330 ohm resistor will be good enough.

If you are messing around with LEDs at home it doesn't matter if you get the current wrong by 10%. Ok, so here I have my 9 volt battery and a 9 volt battery clip.

The red positive wire is going to one side of my 330 ohm resistor, and that's going to the LED's anode.

Then I'm just connecting the negative wire from my battery to the LED's cathode.

9 volts, roughly 20mA, and no exploding LEDs! Finally!

Now I don't have a 300 ohm resistor in my parts collection, but a 330 ohm resistor will be good enough.

If you are messing around with LEDs at home it doesn't matter if you get the current wrong by 10%. Ok, so here I have my 9 volt battery and a 9 volt battery clip.

The red positive wire is going to one side of my 330 ohm resistor, and that's going to the LED's anode.

Then I'm just connecting the negative wire from my battery to the LED's cathode.

9 volts, roughly 20mA, and no exploding LEDs! Finally!

If we increase the resistance to, let's say, 18 kiloohms, we'll get less current, and as you'd expect, the LED is dimmer.

In general, this is the equation you can use to calculate the resistor for a simple LED circuit. But... there is a limitation!

The red positive wire is going to one side of my 330 ohm resistor, and that's going to the LED's anode.

Then I'm just connecting the negative wire from my battery to the LED's cathode.

9 volts, roughly 20mA, and no exploding LEDs! Finally!

If we increase the resistance to, let's say, 18 kiloohms, we'll get less current, and as you'd expect, the LED is dimmer.

In general, this is the equation you can use to calculate the resistor for a simple LED circuit. But... there is a limitation!

I've got another power supply here set to give me 140 volts, and that's enough to mess you up so don't do this at home.

Then I'm just connecting the negative wire from my battery to the LED's cathode.

9 volts, roughly 20mA, and no exploding LEDs! Finally!

If we increase the resistance to, let's say, 18 kiloohms, we'll get less current, and as you'd expect, the LED is dimmer.

In general, this is the equation you can use to calculate the resistor for a simple LED circuit. But... there is a limitation!

I've got another power supply here set to give me 140 volts, and that's enough to mess you up so don't do this at home.

.Let's put 140 volts into this equation, we've got 3 volts for our white LED, and we want to stick to the 20mA current limit.

9 volts, roughly 20mA, and no exploding LEDs! Finally!

If we increase the resistance to, let's say, 18 kiloohms, we'll get less current, and as you'd expect, the LED is dimmer.

In general, this is the equation you can use to calculate the resistor for a simple LED circuit. But... there is a limitation!

I've got another power supply here set to give me 140 volts, and that's enough to mess you up so don't do this at home.

.Let's put 140 volts into this equation, we've got 3 volts for our white LED, and we want to stick to the 20mA current limit.

So we get a resistance value of 6,850 ohms.

I've got a 6.8k resistor in my parts collection, which is very close to our theoretical value, so let's see what happens.

If we increase the resistance to, let's say, 18 kiloohms, we'll get less current, and as you'd expect, the LED is dimmer.

In general, this is the equation you can use to calculate the resistor for a simple LED circuit. But... there is a limitation!

I've got another power supply here set to give me 140 volts, and that's enough to mess you up so don't do this at home.

.Let's put 140 volts into this equation, we've got 3 volts for our white LED, and we want to stick to the 20mA current limit.

So we get a resistance value of 6,850 ohms.

I've got a 6.8k resistor in my parts collection, which is very close to our theoretical value, so let's see what happens.

Now instead of the LED getting toasty, the resistor gets too hot. So what's going on here?

In general, this is the equation you can use to calculate the resistor for a simple LED circuit. But... there is a limitation!

I've got another power supply here set to give me 140 volts, and that's enough to mess you up so don't do this at home.

.Let's put 140 volts into this equation, we've got 3 volts for our white LED, and we want to stick to the 20mA current limit.

So we get a resistance value of 6,850 ohms.

I've got a 6.8k resistor in my parts collection, which is very close to our theoretical value, so let's see what happens.

Now instead of the LED getting toasty, the resistor gets too hot. So what's going on here?

In general, this is the equation you can use to calculate the resistor for a simple LED circuit. But... there is a limitation!

I've got another power supply here set to give me 140 volts, and that's enough to mess you up so don't do this at home.

.Let's put 140 volts into this equation, we've got 3 volts for our white LED, and we want to stick to the 20mA current limit.

So we get a resistance value of 6,850 ohms.

I've got a 6.8k resistor in my parts collection, which is very close to our theoretical value, so let's see what happens.

Now instead of the LED getting toasty, the resistor gets too hot. So what's going on here?

In general, this is the equation you can use to calculate the resistor for a simple LED circuit. But... there is a limitation!

I've got another power supply here set to give me 140 volts, and that's enough to mess you up so don't do this at home.

.Let's put 140 volts into this equation, we've got 3 volts for our white LED, and we want to stick to the 20mA current limit.

So we get a resistance value of 6,850 ohms.

I've got a 6.8k resistor in my parts collection, which is very close to our theoretical value, so let's see what happens.

Now instead of the LED getting toasty, the resistor gets too hot. So what's going on here?

In general, this is the equation you can use to calculate the resistor for a simple LED circuit. But... there is a limitation!

I've got another power supply here set to give me 140 volts, and that's enough to mess you up so don't do this at home.

.Let's put 140 volts into this equation, we've got 3 volts for our white LED, and we want to stick to the 20mA current limit.

So we get a resistance value of 6,850 ohms.

I've got a 6.8k resistor in my parts collection, which is very close to our theoretical value, so let's see what happens.

Now instead of the LED getting toasty, the resistor gets too hot. So what's going on here?

Ohm's Law Now, we will discuss the relation between potential difference and current with an activity

Take nichrome wire actually it is an alloy of nickel chromium manganese and iron

Take an ammeter a world meter and four cells of 1.5 volts each

Procedure: connect ammeter nichrome wire cell and plug key in series and voltmeter in parallel

lithium, sodium, potassium

calcium, strontium, barium

phosphorus, arsenic, antimony

chlorine, bromine, iodine

potassium

calcium

cobalt

phosphorus

lithium, sodium, potassium

sodium, lithium, potassium

potassium ,lithium, sodium

sodium, potassium, lithium

Lother Mayer

Mendeleev

Dobereiner

Newlands

7th

8th

3rd

6th

atomic number

atomic mass

electron number

number of electrons

5

3

2

1

157

93

78.5

75.5

6

7

8

5

cesium

magnesium

barium

sodium

Gregor Mendel was frustrated. he'd studied the work of other plant hybridizers closely, but their observations were general and

their conclusions

fuzzy

Mendel had noticed regular patterns in

the hybrid flowers he grew.

He decided to track traits across

generations

He chose the garden pea for his

experiments because it had clearly

defined traits

He focused on seven contrasting pairs of

traits and crossed plants that differed for each trait to create hybrids

Mendel cross fertilized parent plants by hand when his first crop of hybrids grew they exhibited the characteristics of only one parent

Mendel called this trait the dominant

one the other trait had disappeared

but not forever. When mendel left these

plants to fertilize themselves

the hidden trait returned in the next

generation

Mendel had noticed regular patterns in

the hybrid flowers he grew.

He decided to track traits across

generations

He chose the garden pea for his

experiments because it had clearly

defined traits

He focused on seven contrasting pairs of

traits and crossed plants that differed for each trait to create hybrids

Mendel cross fertilized parent plants by hand when his first crop of hybrids grew they exhibited the characteristics of only one parent

Mendel called this trait the dominant

one the other trait had disappeared

but not forever. When mendel left these

plants to fertilize themselves

the hidden trait returned in the next

generation

outnumbered three to one

by the dominant trait mendel called this traits

recessive.

He chose the garden pea for his

experiments because it had clearly

defined traits

He focused on seven contrasting pairs of

traits and crossed plants that differed for each trait to create hybrids

Mendel cross fertilized parent plants by hand when his first crop of hybrids grew they exhibited the characteristics of only one parent

Mendel called this trait the dominant

one the other trait had disappeared

but not forever. When mendel left these

plants to fertilize themselves

the hidden trait returned in the next

generation

outnumbered three to one

by the dominant trait mendel called this traits

recessive.

Mendel

realized that whatever was governing the

recessive traits was still there in the first hybrids

He focused on seven contrasting pairs of

traits and crossed plants that differed for each trait to create hybrids

Mendel cross fertilized parent plants by hand when his first crop of hybrids grew they exhibited the characteristics of only one parent

Mendel called this trait the dominant

one the other trait had disappeared

but not forever. When mendel left these

plants to fertilize themselves

the hidden trait returned in the next

generation

outnumbered three to one

by the dominant trait mendel called this traits

recessive.

Mendel

realized that whatever was governing the

recessive traits was still there in the first hybrids

deep down in their cells and had been

transmitted to the second generation.

Mendel let these hybrids self-fertilize too.

In their offspring and in later generations a pattern emerged

Mendel cross fertilized parent plants by hand when his first crop of hybrids grew they exhibited the characteristics of only one parent

Mendel called this trait the dominant

one the other trait had disappeared

but not forever. When mendel left these

plants to fertilize themselves

the hidden trait returned in the next

generation

outnumbered three to one

by the dominant trait mendel called this traits

recessive.

Mendel

realized that whatever was governing the

recessive traits was still there in the first hybrids

deep down in their cells and had been

transmitted to the second generation.

Mendel let these hybrids self-fertilize too.

In their offspring and in later generations a pattern emerged

Mendel did the math and concluded that

whatever determined the traits. Mendel did the math and concluded that

whatever determined the traits. we call them

genes were present in the parents in

pairs

But split during reproduction passing to

the offspring in a predictable way. Mendel went on to cross peas that

differed in more than one trait

outnumbered three to one

by the dominant trait mendel called this traits

recessive.

Mendel

realized that whatever was governing the

recessive traits was still there in the first hybrids

deep down in their cells and had been

transmitted to the second generation.

Mendel let these hybrids self-fertilize too.

In their offspring and in later generations a pattern emerged

Mendel did the math and concluded that

whatever determined the traits. Mendel did the math and concluded that

whatever determined the traits. we call them

genes were present in the parents in

pairs

But split during reproduction passing to

the offspring in a predictable way. Mendel went on to cross peas that

differed in more than one trait

The first generation plants were all the same all dominant traits but the second had every possible

combination of traits

Mendel

realized that whatever was governing the

recessive traits was still there in the first hybrids

deep down in their cells and had been

transmitted to the second generation.

Mendel let these hybrids self-fertilize too.

In their offspring and in later generations a pattern emerged

Mendel did the math and concluded that

whatever determined the traits. Mendel did the math and concluded that

whatever determined the traits. we call them

genes were present in the parents in

pairs

But split during reproduction passing to

the offspring in a predictable way. Mendel went on to cross peas that

differed in more than one trait

The first generation plants were all the same all dominant traits but the second had every possible

combination of traits

Again in regular patterns, Mendel

concluded that the elements governing

those traits

were not passed on together

deep down in their cells and had been

transmitted to the second generation.

Mendel let these hybrids self-fertilize too.

In their offspring and in later generations a pattern emerged

Mendel did the math and concluded that

whatever determined the traits. Mendel did the math and concluded that

whatever determined the traits. we call them

genes were present in the parents in

pairs

But split during reproduction passing to

the offspring in a predictable way. Mendel went on to cross peas that

differed in more than one trait

The first generation plants were all the same all dominant traits but the second had every possible

combination of traits

Again in regular patterns, Mendel

concluded that the elements governing

those traits

were not passed on together

Mendel conducted these experiments over multiple generations

patiently growing plants counting peas

and recording patterns for eight years

Mendel did the math and concluded that

whatever determined the traits. Mendel did the math and concluded that

whatever determined the traits. we call them

genes were present in the parents in

pairs

But split during reproduction passing to

the offspring in a predictable way. Mendel went on to cross peas that

differed in more than one trait

The first generation plants were all the same all dominant traits but the second had every possible

combination of traits

Again in regular patterns, Mendel

concluded that the elements governing

those traits

were not passed on together

Mendel conducted these experiments over multiple generations

patiently growing plants counting peas

and recording patterns for eight years

Mendel did the math and concluded that

whatever determined the traits. Mendel did the math and concluded that

whatever determined the traits. we call them

genes were present in the parents in

pairs