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PCB/PCBA knowledge
PCB Resistor – Definition, Significance & How to Choose the Right One

As electronic devices become increasingly complex, circuit boards have become an indispensable part of modern technology. A printed circuit board (PCB) is a thin board that connects electronic components by copper tracks, conductive pathways, or signal tracings.

In this blog post, we will dive deep into PCB resistor and explore its importance. We will discuss why circuit boards have resistors, what the most common type of resistor used on PCBs is, and the difference between an SMD resistor and a normal resistor. 

Table of Contents

What is a PCB resistor?

PCB Resistor
PCB Resistor

Printed circuit board resistors are electronic components that restrict the flow of electric current by converting electrical energy into thermal energy, which is released as heat. Electronic devices use PCB resistor to control the flow of current, safeguard other components from damage, and ensure smooth operation.

Why do circuit boards have resistors?

Almost all circuit boards require a vast array of components to operate effectively. Among those components, resistors are crucial. These small electrical components have a significant function in regulating the flow of current in the circuit board.

Without resistors, the circuitry could easily overload and become damaged due to excessive electrical current.

What is the most common type of resistor used on PCBs?

Engineers and designers commonly prefer fixed resistors for printed circuit boards (PCBs). Axial lead resistors are the most commonly used type of fixed resistor on PCBs. They come in various sizes and shapes and play a crucial role in regulating the flow of electricity in a circuit.

Small cylindrical resistors are cost-effective and widely available, making them suitable for a variety of applications. Their compact size is crucial for today’s electronic devices as they take up less space on the board.

What is the difference between SMD resistor and normal resistor?

There are two main types of resistors: SMD and through-hole. SMD resistors, or surface-mount resistors, are smaller and more compact than their through-hole counterparts. Instead of wire leads that go through a printed circuit board (PCB), they have terminations that are directly soldered to pads on the board’s surface. This design eliminates the need for holes in the board, which means that both sides of the PCB can be used more efficiently. 

SMD Resistor
SMD Resistor

Aside from the size and construction, SMD resistors also have different codes and markings than standard resistors, making them easily distinguishable from one another.

How do you identify a resistor in a PCB board?

To identify a resistor on a PCB board, there are certain important factors that need to be considered. The first and most obvious is the ohm measurement mark, which looks like the Greek letter Omega, or Ω. This symbol tells you the value of the PCB resistor, and it’s crucial for selecting the right replacement if the PCB resistor needs to be replaced.

It is worth checking for any colored bands or stripes on resistors to indicate their value. With some knowledge and observation, identifying a resistor on a PCB board is easy, and it can help in ensuring that your electronics work properly.

How do I choose a PCB resistor?

When choosing a PCB resistor, it’s important to consider certain factors. The resistance needed should be determined beforehand. Additionally, you’ll want to be aware of the power required. This will help you choose a PCB resistor that can handle the amount of energy passing through it without becoming damaged or overheated. 

How do I choose a PCB resistor
How do I choose a PCB resistor

Understanding these key factors will assist you in selecting the appropriate PCB resistor. This will guarantee that your circuit operates smoothly and effectively.

How do I calculate what resistor I need?

Calculating the size of a PCB resistor might sound like a complex task, but it’s actually quite simple. The first thing you need to factor in is your battery voltage and the voltage required by your circuit. Subtract the two values to determine the voltage drop that your PCB resistor will need to achieve in order for your circuit to function correctly. Then, you need to consider the desired current for your circuit.

To find the resistor value you need, simply divide this voltage drop by the desired current. However, keep in mind that this calculation is not a guarantee that the PCB resistor will work flawlessly in every situation. Nevertheless, it is a good initial step to ensure the proper functioning of your circuit.

How to solder resistor on PCB?

Soldering a PCB resistor onto a printed circuit board can be a tricky task, but with the right technique, it can be done smoothly and with ease. First, make sure that the board is clean and free from any loose debris that may hinder the soldering process. Then, insert the PCB resistor leads into the appropriate holes on the board and hold them in place with a pair of needle-nose pliers. Apply a small amount of flux to each lead and heat the soldering iron until it’s hot enough to melt the solder easily.

How to solder resistor on PCB
How to solder resistor on PCB

Once the tip is heated, touch it to the joint between the board and the resistor lead, and apply solder until it melts around the joint. Continue this process on the other end of the PCB resistor until both leads are securely attached to the board. Soldering resistors onto printed circuit boards can become easy and efficient with practice and patience.

How to Solder a Resistor on a Printed Circuit Board PCB

Conclusion

PCB resistors are a helpful component for managing electrical circuits in different applications. They work to adjust currents and voltages to improve safety and efficiency. To ensure the effectiveness of your project, make sure to use the right size of the resistor. Nevertheless, feel free to try different methods and experiments. Doing so can be a captivating way to learn new techniques.

Once you have figured out what kind of PCB resistor you need, it is easy to solder them onto a PCB board. If all else fails, remember that there are plenty of resources available online or even at physical stores if you need help figuring something out. By following these tips on how to understand and work with resistors, you will be able to easily incorporate precise and efficient regulation into your PCB boards.

FAQ

PCB resistors are electronic components that restrict the flow of electric current by converting electrical energy into thermal energy, which is released as heat. Electronic devices use PCB resistors to control the flow of current, safeguard other components from damage, and ensure smooth operation.

Almost all circuit boards require a vast array of components to operate effectively. Among those components, resistors are crucial. These small electrical components have a significant function in regulating the flow of current in the circuit board. Without resistors, the circuitry could easily overload and become damaged due to excessive electrical current.

The first thing you need to factor in is your battery voltage and the voltage required by your circuit. Subtract the two values to determine the voltage drop that your PCB resistor will need to achieve in order for your circuit to function correctly. Then, you need to consider the desired current for your circuit. To find the resistor value you need, simply divide this voltage drop by the desired current.

Kerstin

Author

Kerstin

Hi, I am Kerstin, graduating from one of a well- known university in China and I has a master's degree in physics. I have more than 5 year's experience as a professional engineer in PCB industry and expertise in PCB design, PCB assembly, PCB manufacturing, etc. I am committed to offering services and solutions about PCB/PCBA for various industries for their projects with professional knowledge. During 5 years of engineering career, I have done different circuit designing projects for different companies such as electronics, industry and medical devices, winning a lot of reputation among many customers. Selected as an outstanding employee of IBE every year. I'm always here to provide you with fast, reliable, quality services about PCB/PCBA.

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