Ring Magnet vs Disc Magnet: What is the Difference?

Ring magnets and disc magnets may seem very similar at first glance – after all, they are both circular permanent magnets. However, there are some key differences between these two types of magnets in terms of their shape, magnetic field orientation, and common applications.

In this comprehensive guide, we’ll cover everything you need to know about ring magnets vs disc magnets, including:

• What is a Ring Magnet?
• What is a Disc Magnet (Round Magnet)?
• The Similarities Between Ring and Disc Magnets
• 3 Key Differences Between Ring and Disc Magnets
  • Difference #1: Center Hole
  • Difference #2: Magnetic Field Orientation
  • Difference #3: Common Applications

You’ll also discover real-world examples of how ring and disc magnets are used, let’s get started!

What is a Ring Magnet?

A ring magnet is a doughnut-shaped circular magnet that has a hole in the middle, resembling a ring.

Ring magnets are most often made of strong magnetic materials like neodymium or samarium cobalt. They generate an intense magnetic field while being relatively small in size.

The key feature of a ring magnet is the presence of the circular center hole, which allows the magnet to slide over other components like rods or bearings. This makes them highly adaptable for a wide variety of applications (more on this later).

What is a Disc Magnet?

A disc magnet (also referred to as a round magnet or button magnet) has the same overall circular shape.

However, unlike ring magnets, disc magnets are solid all the way through with no center hole. They are flat on each circular side, resembling a disc or hockey puck.

Disc magnets are available in a wide range of sizes, from just a few millimeters across to several inches in diameter. Small disc magnets are often used for crafts, experiments, and DIY projects. Large industrial-grade disc magnets have extremely strong magnetic fields and can lift thousands of pounds.

Now that you understand the basic physical characteristics of ring and disc magnets, let’s look at how they are similar and different.

The Similarities Between Ring Magnets and Disc Magnets

While ring and disc magnets have some clear physical differences, they do share the following similarities:

• Permanent magnets: Both ring and disc magnets create permanent magnetic fields, meaning they act as magnets all the time. (As opposed to temporary electromagnets which only produce magnetic fields when electrical current flows through a coil).
• Polar orientation: Ring and disc magnets have “north” and “south” poles on opposite sides, with the magnetic field looping from the north pole to the south pole internally.
• Available materials: Ring and disc magnets can both be made from strong magnetic materials like neodymium (NdFeB), samarium cobalt (SmCo) and alnico. Some ceramic (ferrite) magnets are also available in these configurations.
• Circular shape: Both magnet types have an overall circular shape when viewed from the top, although the disc is solid while the ring has a center hole.

Now let’s look at three of the most significant differences between these two magnet types that set them apart in terms of applications and capabilities.

3 Key Differences Between Ring Magnets and Disc Magnets

Difference #1: Center Hole

The most obvious physical difference between ring magnets and disc magnets is the presence or absence of the center hole.

Ring magnets have an open space in the middle that allows them to slip over rods, bearings, shafts, screws, tubes and other cylindrical components. This versatility allows ring magnets to interface with moving parts in motors, electric generators, bearings, and other mechanical systems.

The hole also affects the orientation and shape of the magnetic field. Ring magnets project more of their magnetism outward from the outer circumference rather than the thin inner section.

Disc magnets, on the other hand, do not have a center hole allowing them to fit over other components. The solid disc shape leads to a strong magnetic field projecting perpendicular from the flat circular faces on either side.

Difference #2: Magnetic Field Orientation

Due to the difference in shape, ring magnets and disc magnets have different magnetic field patterns.

Ring Magnet Field Orientation

Ring magnets have magnetic poles located on opposite sides of the outer ring, with the field looping around the center hole. Think of this like a circular racetrack with the magnetic field following the ring around from the north pole to the south pole.

The presence of the hole heavily influences the magnetic field pattern so more magnetism projects from the outer perimeter of the ring. This gives ring magnets a longer reach and allows them to exert magnetic force at a greater distance.

Disc Magnet Field Orientation

Disc magnets project an evenly distributed magnetic field perpendicular to the flat circular faces of the magnet. The magnetic poles are on directly opposite flat sides, with the field moving directly through the solid material of the magnet.

The solid disc shape means the magnetic flux density is similar across the circular faces of the magnet with minimal shaping around any internal openings.

Difference #3: Common Applications

Due to the variations in shape, dimensions, and magnetic field properties we’ve covered, ring magnets and disc magnets tend to excel in different real-world applications.

Ring Magnet Applications

Ring magnets are commonly used in motors, bearings, generators, electric instruments, loudspeakers, and an assortment of sensing, scientific, and industrial applications.

Examples include:

• Rotors in electric motor components
• Securing bearings of various types
• Holding and controlling sensors (like Hall effect sensors)
• Focusing electron beams
• Lifting and transporting small metal objects

The ring shape essentially turns the magnet into a very powerful, precise clamp able to grasp onto components, holding them securely in place even in dynamic systems.

The open center hole is the key to most ring magnet applications, allowing them to slide onto other parts and hold position reliably.

Disc Magnet Applications

Disc magnets are commonly used where a flush contact surface is needed, not requiring any open center space.

Examples include:

• Mounting signs, photos, artwork and accessories to metal surfaces
• Holding doors open
• Magnetic closures on jewelry boxes, guitar case latches, refrigerator doors, etc.
• Mounting metal plates to hold tools, knives or workshop accessories in place
• Lifting and picking up small metal objects (paperclips, pins)
• Building magnetic sculptures, toys, decor items and more (refrigerator magnets)

The strong flat magnetic face of disc magnets gives them incredible holding power through direct contact, not always needing a protruding component to grip onto.

Of course, there is some overlap in potential applications, but in general ring and disc magnets each excel due to their specific shape and magnetic field alignment.