Computer

What Are PCB Standoffs and How Are They Used

The printed circuit board is a very critical component in all electronic gadgets. It is the core component in computers, cell phones, and laptops. A PCB is made effective by the use of standoffs which must be used to hold it in place.

What is a PCB standoff?

A standoff is a threaded separator that comes in a specific length. It is used to raise the printed circuit board above the surface and keep it stable. The standoffs keep the PCB parts in the interior of the computer chassis elevated and stationary. The parts are kept from touching each other, preventing the risk of electrical shorts. 

Standoffs are often made using brass, aluminum, or nylon and they come in female-female or male-female forms. They are either round or hex-shaped to facilitate wrench tightening of each part. They are available in a variety of sizes and shapes.

How are PCB standoffs used? 

PCB standoffs are used to raise the board from the metal case. This helps to ensure there is no conductive part at the bottom of the board that can cause an electrical short. An electrical short is bound to happen if multiple conductive lanes touch the board.  The standoffs work to prevent such situations from happening. 

PCB standoffs look very peculiar – like a little screw. On one end they have threads like a normal screw while the other has a hole. The end with threads is used to mount the standoff onto a surface like the PC case. The end with the hole is threaded inside and is used to screw the standoff on the motherboard once it is mounted on a case.     

Is it necessary to use standoffs? 

It is necessary to use standoffs in the assembling of electrical gadgets. They keep the electrical of the circuit board away from the conductive metal which makes up the case. 

This ensures there is a good flow of air at the bottom of the board to prevent overheating. The free space allows the board to cool down while in use and enjoy free movement of the air.  

Standoffs also lock the board to the case securing all the components to avoid loss or damage. These crucial screw-like parts keep the space under the motherboard clear. This is to eliminate the risk of electrical shorts and damage. Electrical parts should never be tightly packed as the risk of shorts is high. Always keep them well spaced and airy for the best performance. 

What material are standoffs made of? 

Standoffs are made from a variety of materials – ceramic, plastic and metallic.  

  • Ceramic standoffs are used in extremely high-temperature applications. 
  • Plastic standoffs such as nylon ones offer excellent corrosion resistance. These are also cost-effective and preferred over metal because they are lightweight.  
  • Metallic standoffs are the most commonly used ones.

Types of standoffs

Standoffs come in different types that help support and fasten the PCB mounting. They include:

  • Snap lock – They push into the panel, snapping into place to give a reliable and secure fix.  
  • Male/female threaded – Used with screws or nuts to give a secure fixing that can be retightened in the future or loosened. 
  • Snap-fit – They are efficient, quick, and easily releasable. They save you mounting time during mass installation.
  • Adhesive base – does not need a mounting hole, rather, provides time and space efficiency.  
  • Blind hole/ press-fit – They are best used with threaded holes or in places where there are no through holes.

How to choose the right standoff

Your PCB layout design always dictates the standoffs that should be used. We hereby give you an overview of what you should consider.

  • Know the application you are working with. Different applications require different standoffs. Snap-fit is best used in the fiberglass PCBs to deliver the kind of strength and flexibility needed. Paperboard PCBs are more rigid so they use blind hole/press-fit to give support without penetrating the PCB. If you are using multiple PCBs, use the support that has a wing or an arrowhead connector. This is best for use on boards that have a lower weight that can tolerate stacking. 
  • Consider the material you want to use. Do you want metallic, plastic, or ceramic standoffs? 
  • Choose materials that are:  
    • Resistant to corrosion
    • Lightweight
    • Non-conductive
    • Cost-effective 
  • Choose the mounting style you want. The mounting style should also help you in choosing the right standoff. These styles include:
  • Snap lock – snaps, and locks into a chassis hole with a secure but easily releasable fix
  • Threaded – holds in position with a nut to give a secure fixing
  • Press-fit – holds securely to a range of binding holes with a unique pointing style
  • Push-fit – pushes into a chassis hole for a firm fix
  • Adhesive base – Provides a secure hold without puncturing holes in the PCB

Whether you need conductivity or insulation, you can enhance functionality using different standoffs.  The manufacturers have made it easy for you to get the right standoffs for your usage. A wide range of options enables you to get the right tool for the right job! 

Final thoughts

The importance of standoffs cannot be overlooked. They are not an option, rather, a necessity that every electrical gadget uses. They serve a very important role in ensuring the motherboard never comes into contact with the case, thus, preventing electrical shorts. Their work cannot be replaced by any other product.  

PCB standoffs come with a compatible case for your board. Your circuit board will have matching holes for the standoffs to fit and secure it. 

These holes dictate where the standoffs should be placed. This is usually at a location close enough to the I/O shield so that the ports can be easily accessible from outside the case.

Remember, a misplaced standoff can touch the conductors of the printed circuit board and short it. Always handle the standoffs with the utmost care. Do not screw them too tight as they may break the board or refuse to unlock when you want them to.     

ABHIYAN
the authorABHIYAN
Abhiyan Chhetri is a cybersecurity journalist with a passion for covering latest happenings in cyber security and tech world. In addition to being the founder of this website, Abhiyan is also into gaming, reading and investigative journalism.

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