How do resistors work? (Animated) | Basic Electronics

Summary

This script delves into the ubiquity and versatility of resistors in electronics, highlighting their use in various applications like operational amplifiers and current limiters. It introduces different types of resistors, from the common axial lead to the tiny 0603 and the massive ones used in heavy machinery. The explanation covers the basics of resistors, including their symbols, physical appearances, and how to choose them based on resistance, power rating, tolerance, and thermal coefficient. The importance of Ohm's law for understanding their function in circuits is emphasized, along with their linear behavior and minimal impact on high-frequency designs.

Takeaways

• 💡 Resistors are the most common electronic components and are used in a wide range of applications like operational amplifiers, voltage dividers, and current limiters for LEDs.
• 🛠️ There are different resistor symbols: European and American, which are quite similar, making them easy to recognize on schematics.
• 📏 Resistors come in various shapes and sizes, from tiny surface-mount resistors to large chassis-mounted ones used in high-power applications.
• 🎨 The most stereotypical resistor is an axial lead quarter-watt through-hole resistor, typically identified by its color bands indicating resistance and tolerance.
• 🔍 Resistors have low parasitic inductance and capacitance, making them highly linear and easy to use in most circuits except for high-frequency applications.
• 🌊 Resistors work by resisting the flow of electrons, similar to how a smaller pipe restricts water flow in a hydraulic system.
• 📐 Ohm's law (V = IR) is fundamental in understanding resistor behavior, linking voltage, current, and resistance in a linear relationship.
• ⚠️ When choosing a resistor, consider its resistance, power rating, tolerance, and thermal coefficient to ensure it meets the circuit's requirements.
• 🔥 The power rating is crucial, as exceeding it can cause the resistor to overheat or fail, especially in high-power circuits.
• 📦 For most prototyping or hobby projects, standard resistors with typical tolerance and power ratings are sufficient, but more precise options are available for critical applications.

Q & A

What is the most common electronic component in the world according to the script?

The resistor is considered the most common electronic component in the world.

What are some common uses of resistors in electronic circuits?

Resistors are used in setting up operational amplifiers, creating feedback loops, voltage dividers, and as current limiters for LEDs, among other applications.

What are the two different resistor symbols mentioned in the script?

The script mentions the European and the American (or more standard) resistor symbols.

What is an axial lead quarter watt through-hole resistor?

It is a stereotypical resistor with color bands indicating resistance and tolerance, commonly used in electronics.

What is the significance of the color bands on a resistor?

The color bands on a resistor indicate its resistance value and tolerance, which are crucial for its operation in a circuit.

What are some of the different sizes of resistors mentioned in the script?

The script mentions 0603 resistors, which are tiny, and 0402 resistors, which are even smaller. It also talks about much larger resistors used in applications like elevator control boards.

Why are resistors considered easy to use in electronic circuits?

Resistors are easy to use because they are highly linear, meaning the current changes linearly with voltage, and they have minimal parasitics that can usually be ignored unless working with RF circuits.

What is the basic principle of a resistor in terms of electron flow?

A resistor slows the flow of electrons through a circuit, acting like a point where the 'pipe' gets smaller, thus reducing the current or water flow in the analogy provided.

How is the relationship between voltage, current, and resistance described in the script?

The relationship is described using Ohm's law, which states that voltage (V) equals current (I) times resistance (R), or V = IR.

What are some factors to consider when choosing a resistor for a circuit?

When choosing a resistor, one should consider its resistance value, power rating, tolerance, thermal coefficient, and inductance or capacitance if working with high-frequency circuits.

Why is it important to consider the power rating of a resistor?

The power rating of a resistor is important because exceeding the rated power can cause the resistor to overheat and potentially fail, affecting the performance and safety of the circuit.

What is the role of the tolerance value in a resistor and why might someone choose a lower tolerance?

The tolerance value indicates the acceptable variance in the resistance value from the nominal value. Choosing a lower tolerance is important for applications requiring higher precision, though it typically comes at a higher cost.

How does the thermal coefficient affect the performance of a resistor?

The thermal coefficient affects the performance of a resistor by causing changes in resistance with temperature variations. This is important to consider in circuits that will operate in extreme temperature environments to ensure consistent performance.

What is the script's suggestion for hobbyists and prototypers regarding resistors?

The script suggests that for most hobbyists and prototypers, standard resistors are sufficient for their projects, and they can start using smaller resistors for PCBs to make their circuits more compact as they advance in their skills.

Outlines

00:00

📏 The Ubiquity and Basics of Resistors

This paragraph introduces resistors as the most common electronic components, used in various applications like operational amplifiers, voltage dividers, and current limiters. It explains that resistors come in different forms and sizes, from the standard axial lead through-hole resistors to much smaller surface mount resistors like the 0603 and 0402 types. The paragraph also touches on larger resistors used in industrial applications, emphasizing the diversity in resistor packages and their ubiquity in electronic circuits. Additionally, it highlights the simplicity of the resistor symbol in schematics and the differences between European and American standards.

05:01

🔥 Understanding Resistor Characteristics and Applications

This paragraph dives deeper into the characteristics of resistors, including their linear behavior, the importance of Ohm's Law (V=IR), and how resistors control the flow of electrons in a circuit. It discusses key factors to consider when selecting a resistor, such as resistance value, power rating, tolerance, and thermal coefficient, and how these factors can impact circuit performance in different environmental conditions. The paragraph also notes that while resistors are generally straightforward, in high-frequency circuits, considerations of parasitic inductance and capacitance become important. It concludes by reassuring hobbyists that for most prototyping tasks, standard resistors are sufficient, but more precise components may be needed for advanced or production-level designs.

Keywords

💡Resistor

A resistor is an electronic component that opposes or limits the flow of electrical current in a circuit. It is a fundamental part of many electronic devices and is used for various purposes such as voltage division, current limitation, and feedback in operational amplifiers. In the script, the speaker emphasizes the ubiquity of resistors, noting their presence in almost every electronic device and their various roles in circuit design.

💡European and American Resistor Symbols

These refer to the graphical representations used in circuit diagrams to denote resistors. The script mentions that while the symbols may vary slightly between European and American standards, they are quite similar, aiding in the universal understanding of circuit schematics.

💡Axial Lead

An axial lead resistor is a type of resistor with leads (wires) extending along the axis of the resistor body. This is a common form factor, especially in through-hole technology, and is characterized by its color bands that indicate resistance value and tolerance. The script uses the axial lead resistor as an example of the 'stereotypical' resistor.

💡Color Bands

Color bands on a resistor are a visual coding system that indicates its resistance value and tolerance. Each color corresponds to a specific number, and the arrangement of these colors allows for quick identification of the resistor's specifications. The script explains that these bands are a key feature of the axial lead resistors.

💡Tolerance

Tolerance in the context of resistors refers to the permissible variation in the actual resistance value from the specified value. It is usually expressed as a percentage and is an important parameter to consider when selecting a resistor for a circuit. The script mentions that most resistors have a 5% tolerance, but higher precision resistors with tighter tolerances are available at a higher cost.

💡Power Rating

The power rating of a resistor is the maximum amount of power it can dissipate without overheating or failing. It is crucial to ensure that the resistor used in a circuit can handle the power it will be subjected to, as exceeding this limit can lead to component failure. The script warns about the importance of not exceeding the power rating, especially in the context of different resistor sizes and applications.

💡Ohm's Law

Ohm's Law is a fundamental principle in electrical engineering that relates voltage, current, and resistance in a circuit. It is expressed as V = IR, where V is voltage, I is current, and R is resistance. The script uses Ohm's Law to explain the linear relationship between these quantities and its importance in understanding and designing circuits.

💡Inductance

Inductance is a property of an electrical component that describes its ability to store energy in a magnetic field when current flows through it. While resistors are generally considered to have minimal inductance, the script notes that all resistors have some inductance, which can be significant in high-frequency applications.

💡Capacitance

Capacitance is the ability of a component to store energy in an electric field. Similar to inductance, while resistors are not primarily capacitive, they do possess some level of capacitance. The script mentions that in high-frequency circuits, it's important to consider or minimize the capacitance of a resistor.

💡Thermal Coefficient

The thermal coefficient of a resistor refers to the change in resistance with temperature. It is an important factor to consider in circuits that operate over a wide temperature range, as it can affect the performance and stability of the circuit. The script advises checking the thermal coefficient to ensure that temperature changes do not significantly alter the resistance value.

💡Prototyping

Prototyping in electronics is the process of creating a preliminary model of a circuit or device to test and evaluate its design. The script suggests that for most prototyping and hobbyist work, standard resistors can be easily used in projects without the need to worry about the finer details discussed for production-level designs.

Highlights

Resistors are considered the most common electronic components used in a wide range of applications.

Resistors are used in operational amplifiers for feedback loops, voltage dividers, and as current limiters for LEDs.

The European and American resistor symbols are similar, making them easily recognizable.

Physical resistors can vary greatly in appearance despite having consistent schematic symbols.

Axial lead quarter watt through-hole resistors are a common and recognizable type with color bands indicating resistance and tolerance.

Resistors come in various sizes, from tiny 0603 to larger chassis and panel mount types.

The smallest resistors can be challenging to solder, with some sizes requiring a microscope.

Resistors are available in a wide range of power ratings, from quarter-watt to hundreds of watts.

Resistors are highly linear, with current changing linearly with voltage, and minimal parasitic effects.

Ohm's law (V=IR) is fundamental for understanding the behavior of electricity through resistors.

Choosing a resistor involves considering resistance, power rating, tolerance, and thermal coefficient.

Resistors' tolerance can vary from 5% to as precise as 0.001%, affecting their cost.

The thermal coefficient of a resistor is crucial for circuits operating in extreme temperatures.

High-frequency circuits require resistors with minimal inductance and capacitance.

Resistors are simple to use and ideal for most prototyping and hobbyist projects.

For production-level designs, attention to resistor details becomes more critical.

The video encourages viewers to visit circuitbread.com, like the video, and subscribe for more content.

Transcripts

So I don't have any data to back this up,

But I feel pretty confident in saying that

The resistor is the most common electronics component in the world.

It is used in practically everything.

It's used in setting operational amplifiers, getting that feedback loop setup,

voltage dividers, current limiters for LEDs and so many other things.

They're just everywhere.

So we're gonna go over that really quick and we're going to learn more about resistors

and what we should pay attention to with them.

So the resistor symbol is actually very straightforward.

There's the European resistor symbol,

and then there's the American or the most

Well, for Americans, more standard resistor symbol.

And as you see, they are actually quite similar.

So that's pretty nice.

However, the challenge comes when you're looking at the actual physical resistor itself.

Even though on your schematic they look the same,

in reality, resistors look wildly different.

So I have here what one would consider the most stereotypical resistor.

And this is an axial lead quarter watt through-hole resistor

and this is when people think of resistors, basically, what you think of.

It's got the color bands to show you exactly what the resistance is

As well as a band showing the tolerance of this.

And so this is the stereotypical resistor.

However, resistors come in all shapes and sizes.

So I also have here with me a small bag of resistors.

Now. These are 0603 resistors.

And they are absolutely tiny and they're not even close to the smallest they have out there.

The smallest one that I am able to actually solder is an 0402.

Which is quite a bit smaller than this

and the smallest ones are so small

I wouldn't even try, even using my microscope, to solder.

They're so small.

And resistors also come in the other size.

They get huge.

My father-in-law makes elevators and he designs control boards

and he uses these massive brown o'my resistors

to control the flow of electricity when necessary.

And when I first saw that, I was still in school

and I did not believe that they were resistors.

I thought my wife was just messing with me.

But no. You can see resistors in all shapes and sizes.

So if you see something and somebody says it's a resistor,

They're probably not lying too

Even if you've never seen it in that package before.

So don't be surprised if you have some that are through-hole, that are surface mount.

As you saw here, they're chassis mount, panel mount, any variety.

Again, since the resistors are so ubiquitous

They are in every package style, every mounting style that you can imagine.

So now the good news is that resistors are very easy to use.

They're highly linear.

As the voltage changes, the current through them changes linearly.

There's not much that you have to worry about in terms of parasitics.

There is a little bit of inductance and a little bit of capacitance.

But it's so tiny that most the time you just completely ignore it unless you're doing RF circuits.

And frankly, they're just very straightforward.

So the basis of a resistor is that, as the resistors put into the circuit,

The electrons go to it and it slows that flow of the electrons.

It resists the flow of electrons so that you won't have nearly as much going through it.

So very frequently, when people use water as an analogy

A resistor is like basically a point

where the pipe gets smaller

so the water struggles to get through it.

So, a bigger pipe means lower resistance.

Smaller pipe means higher resistance.

Less current or less water flow, using that analogy.

Now the behavior of electricity through resistor

is very easily described using Ohm's law.

V equals IR or voltage equals current times resistance.

Now I'd like to emphasize this law because it's so important

To get a fundamental understanding of how electricity works.

Now going back to that analogy,

You can see that voltage, which is the pressure

Pushing the water versus the current which is the actual flow of the water

Would be related to the size of the pipe.

So Ohm's law shows that linear relationship

And is really helpful to get an intuitive understanding of what to do when you're trying to set the current

or control the current in a circuit.

So when you're choosing a resistor

Some of the most important things to figure out is obviously the resistance.

That's the biggest one.

But you also need to know what the power reading is.

How much current and at what voltage is going to be through and across this resistor

Because too much power and too small of a resistance.

Again, this is a quarter watt resistor.

You try and put too much power through this thing,

And you are going to have some serious issues.

That large resistor in the picture from the elevator controller

That obviously is more in the tens to hundreds of watts.

Where these are more in the quarter two tenths of watts.

So again, figure out the resistance,

the power and dissipation capabilities.

You also want to know the tolerance.

Most resistors like this, the tolerance is 5%.

You want to pay more to get more like 1%

You can even get down, I think, to .01, .001%

Of course, the price just keeps on ramping up

And if you don't need that sort of precision,

You usually want to design around it and you don't want to pay for it.

And then finally, the thermal coefficient.

You want to make sure that as you're in a hot place or cold place,

It's not going to throw off the resistance of your resistor.

Because you could have your circuit in the Antarctic

and it acts one way or the Sahara and it acts another way.

You want to make sure that you either have a resistor

that doesn't have an issue with that temperature coefficient or you're gonna design your circuit

so that any sort of deviation from that ideal resistance is not a big deal.

Finally, as I mentioned earlier, resistors are great

In that they're very linear and they don't get affected by frequency.

However, again in reality, all of them have a little bit of inductance and a little bit of capacitance.

So if you're gonna be doing a high frequency circuit

You want to be making sure that your resistor has minimal capacitance or minimal inductance

or at least that you know what it is so that you can take that into account

When you're designing your circuit.

And that's really it.

Resistors are very straightforward but incredibly powerful.

And for the most part you can just drop them in and it's not until you start doing More production level designs

that you need to worry about.

Exactly all of those tiny little details, but for most just prototyping hobbyists work.

You can just buy a package of these things and use them in almost every single project you have.

And then from there, change what you need and if you're going to start doing your PCBs

You can start buying these tiny ones so that you can make your circuits even smaller.

Alright, that's it for now.

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