Beginner Guide for Through Hole PCB Assembly

Through-hole PCB assembly is an essential process in the fabrication of printed circuit boards. It involves assembling components onto the board through manually soldering or using a wave soldering machine, ensuring that all connections are secure and stable. But what benefits does this assembly offer, and what components are used?

In this article, we’ll explore these questions and more as we dive into the world of through-hole PCB assembly. So, grab your soldering iron and let’s get started!

Table of Contents

What is a through-hole assembly?

Through-hole assembly is the process of mounting components onto a printed circuit board (PCB) by inserting them through holes in the board, and then soldering them in place. This method offers a number of advantages over other assembly methods, including increased reliability and accuracy when it comes to soldering.

Through-hole assembly also allows for greater flexibility when it comes to component placement, since components can be placed on both sides of the PCB. Commonly used components for through-hole assemblies include resistors, capacitors, diodes, transistors, and integrated circuits. With careful attention to detail during each step of the process—from drilling the holes to soldering each component—through-hole assembly ensures that your PCB will perform reliably for years to come.

Benefits of Through-Hole PCB Assembly

One of the key benefits of through-hole PCB assembly is its reliability. By inserting components through drilled holes in the PCB and soldering them in place, you can be sure that your board will perform reliably for years to come. Through-hole assemblies also offer greater flexibility when it comes to component placement, since components can be placed on both sides of the board. Additionally, this method of assembly allows for improved accuracy during soldering.

Another is its cost-effectiveness. This process is generally less expensive than surface mount technology (SMT) and is therefore a good choice for those working on smaller budgets or with limited timeframes. The components used in through-hole assembly are often more affordable than those used in SMT, making them a great option for hobbyists and small startups who need to save money.

Finally, through-hole assemblies are easier to troubleshoot in comparison to their SMT counterparts due to their larger size and more exposed components. This makes repairs simpler and cheaper than they would be with an SMT board. In addition, if you ever need to replace a component in an assembled PCB, it’s much easier to do so with through-hole technology than with SMT boards due to the large number of exposed connections available for easy access.

Components Used for Through-Hole PCB Assembly

Through-hole PCB assembly is a great way to create reliable and durable circuits. With the right components on hand, you’ll be well on your way to creating a successful project! 

Hole Component

Hole components are an integral part of through-hole PCB assembly. These components, which come in a variety of shapes and sizes, are inserted into pre-drilled holes in the board to provide a secure physical connection between components and their leads.

Common hole components include pins, sockets, plugs, and headers. Pins are used to connect components to the board and are typically made from either plastic or metal. Sockets accept removable plugs that can be changed out as needed and also come in both plastic and metal varieties. Plugs can be found in a variety of shapes and sizes and fit snugly into sockets when inserted.

Electrolytic Capacitor

Electrolytic capacitors are an essential part of any through-hole PCB assembly. These components store and release electrical energy and can be used to filter signals or smooth out power supplies. They’re usually cylindrical in shape, with two metal plates separated by a layer of electrolyte. Electrolytic capacitors come in a variety of shapes, sizes, and voltage ratings to meet the needs of any application.

When installing electrolytic capacitors into your board, it’s important to pay attention to their orientation – the positive lead is usually marked with a plus sign (+) or another symbol. When connecting the capacitor’s leads to the board, make sure that they’re firmly inserted into the holes and that they don’t touch each other or any other components on the board. It’s also important to make sure that you select a capacitor with the proper voltage rating for your application – using one that is too weak could lead to damage or malfunction!

Radial Component

Radial components are an important part of any through-hole PCB assembly. These components are used to connect parts of the board, such as traces and pins, to other parts or components on the board. Radial components come in a wide range of shapes and sizes, from tiny 0201 SMD resistors to large power connectors.

When installing radial components onto your PCB, it’s important to pay attention to the placement and orientation of each component. For example, if you’re using a radial capacitor, make sure that the positive lead is placed towards the edge of the board. It’s also important to make sure that the leads are properly aligned with their respective holes on the board – this will help ensure that all connections are secure and reliable.

Larger/Heavier Component

Larger and heavier components are essential for any through-hole PCB assembly and can range from large power connectors to heavy metal heatsinks. These components need to be carefully selected and installed in order to ensure that your board functions properly.

Manual Soldering for Through-Hole PCB Assembly

Manual soldering is an important step in through-hole PCB assembly. It requires precision, patience and the right tools in order to ensure a successful result.

Solder Joints and Quality of Joints

Solder joints are the most important factor to get right in through hole assembly. A good solder joint should be strong, secure and have a smooth, shiny appearance. It’s also important that each solder joint has plenty of heat transfer in order to ensure a successful connection.

The quality of your solder joint is determined by several factors, such as the temperature of your soldering iron, the amount of flux used and the type of solder you use. Additionally, there are certain techniques that can help you achieve optimal results with your solder joints—such as using rosin core or no-clean flux and avoiding bridging between components.

Placement of Components on the Board

The components must be placed in their correct locations so they can properly connect with each other, as this will ensure that your circuit functions as intended. To get it right, you need to carefully read the schematics and double-check that all components are being placed in the right spots.

It’s also important to pay attention to component orientation. Some components have specific directional requirements and using them in an incorrect orientation can cause serious damage or even permanent failure. Additionally, some components may require additional parts such as jumper wires or standoffs for optimal performance—so make sure you have all of these before beginning assembly.

Placement of Components on the Board

Tin-lead solder is a traditional choice for this purpose, as it’s relatively easy to work with and provides a strong connection between components. However, tin-lead solder contains lead which has been linked to environmental concerns, so some manufacturers are now moving away from this option.

There are several alternatives that offer excellent performance while being more environmentally friendly. Solders made from silver or copper can provide a solid electrical connection and have low melting points that make them easier to work with than tin-lead solders. There are also lead-free solders available that contain no lead at all, but these have higher melting points and may require special fluxes for optimal results.

No matter what type of solder you choose for your through-hole PCB assembly project, just make sure you follow the manufacturer’s instructions closely—especially when it comes to the soldering temperature—to ensure the best possible results!

Wave Soldering for Through-Hole PCB Assembly

Wave soldering is a popular method of through-hole PCB assembly, and it involves passing a printed circuit board over a wave of molten solder. As the board moves along the conveyor, metal components are inserted into the holes on the board in order to create an electrical connection. The molten solder then forms a bond between the components and the board.

Wave soldering is great for mass production because it’s fast and efficient, but it can also be used for smaller projects as well. It’s important to make sure that each component is properly placed before running it through the wave, as any misalignment could cause problems with your finished product. Additionally, you’ll want to make sure that your flux levels are correct and that there are no contaminants in the solder bath, which can lead to poor connections or corrosion.

Steps Involved in the Wave Soldering Process

The wave soldering process involves several steps that must be completed in order to ensure a successful assembly. The first step is to clean the printed circuit board by removing any dust or debris from its surface. This helps to ensure a good connection between the components and the board.

Next, flux must be applied to the printed circuit board in order to prepare it for soldering. The flux protects against oxidation and prevents corrosion of the metal components during soldering.

Once the flux has been applied, each component is carefully placed into its designated hole on the board before being sent through the wave of molten solder. As it passes through, each component forms an electrical connection with the board as well as with its neighboring components.

Finally, after passing through the wave, excess solder is removed by using a flux-removing solution and then cleaned with a brush or cloth. Once all of these steps have been completed, your PCB assembly is ready for testing!

Design Considerations for Through-Hole PCB Assembly

Through-hole PCBs require a lot of precision and accuracy when it comes to drilling holes, so it’s essential to choose the right tools for the job. When selecting drill bits, be sure to consider their size, material, and cutting speed in order to ensure maximum performance. Additionally, larger components may require larger drill bits and extra care must be taken to reduce potential damage during the drilling process.

It’s also important to take into account the type of board you’re working with when considering design considerations for through-hole PCB assembly. Different materials require different levels of insulation and may require specialized tools for proper assembly. In addition, boards with multiple layers need special attention when it comes to hole placement and other factors that affect their overall design.


Through-hole PCB assembly is a popular method of creating electronic circuits and components, and it involves passing a printed circuit board over a wave of molten solder in order to form electrical connections.

Wave soldering is great for mass production due to its speed and efficiency, it can also be used for smaller projects as well. PadPCB is the leading supplier for PCB manufacturing and assembly, we can offer small batch of PCB assembly service. 


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