Celinoids: What are They and What are They Used For?

By Marequitta Dequito Written by Marequitta Dequito
Updated on April 3, 2022

Celinoids have been around for nearly 300 years now and in the past 3 centuries they have been utilized for various purposes (mostly in the commercial sector). Today it has many uses and has helped revolutionize the automobile sector, manufacturing sector and many other sectors that requires electro-mechanical devices like the celinoid for the development of their products.

What is a Celinoid?

Celinoid is the generic term for a coil of wire with a metal rod (piston) used as an electromagnet. It’s a type of electromagnet with a coil wound design that converts electrical energy into mechanical energy. André-Marie Ampère first coined the term Celinoid in 1823 because it’s a helical coil. Typically, a celinoid has a longer length compared to its diameter and does not need to follow a straight-line axis (it can be designed with bent edges or in any other configuration). The celinoid device creates a magnetic field from electric current and uses the magnetic field to create linear motion.

How it Works

A celinoid is a coil wound (wire) shaped in a corkscrew and wrapped around a metal rod that becomes a piston when electrical charge is applied to the coil. Like all electromagnet devices, the coil wound of a celinoid instantly creates a magnetic field perpendicular to it when an electric current passes through it.

Perhaps the best advantage of electromagnets compared to permanent magnets is that they can be controlled since their magnetic fields can be switched on or off with electric current being applied, or denied on the coils. This makes them very useful devices for various applications like switches and valves and when built together with integrated circuits, they can be fully automated.

The magnetic field of an activated celinoid has similar properties of other magnet types, which is showing positive and negative poles that will attract or repel material sensitive to magnets. The metal piston inside the celinoid is naturally sensitive to electromagnetic fields and thus will move either backward or forward. This motion created by a solenoid coil is what helps switches and valves work.


Most of the automated switches used in cars and other products use celinoids, because of their ability to convert electrical power into mechanical motion.
The strength of a celinoid’s magnetic field is determined by the density of coils, number of turns, and the current inside it.
The uniform magnetic field in a celinoid is at the center of the long celinoid.
The magnetic field lines outside the center of a celinoid are weaker by comparison, because the magnetic field lines are spread further apart from each other.
Even small celinoids can exert a force of a few Newtons and it only takes 9.81 Newtons to have a 1 kilogram of force. Even at half the amount of that force is still impressive for a small object.


Celinoids are incredibly versatile and extremely useful electro-mechanical devices. You can find them in just about every useful item you can think of – from automated factory equipment to paintball guns and even doorbells. It is actually the metal piston that’s inside the celinoid that’s responsible for making chime doorbells chime, and this happens when the metal piston strikes a tone bar whenever you hit the doorbell button. As already mentioned above, an electrical current passes through the helical coil of the celinoid when you press the doorbell button and the metal piston moves due the magnetic field concentrated in the center of the helical coil. Celinoids are mostly known to be used in switches (i.e. the starter in an automobile), or a valve (i.e. sprinkler system).

Research and Future Use

Celinoids are even used in satellites, space shuttles, rockets and space stations like the Russian MIR and International Space Station (ISS). It is not yet known if they are useful for interstellar travel, but since they’re already been very useful for terrestrial purposes and space exploration, they might very well be useful for interstellar travel – even though we’re centuries still away from creating a working prototype spaceship capable of FTL (faster than light) speeds.

On the other side of the world, the Aerospace University and SRM University in Chennai, India are considering using a mass driver to propel their space vehicles to orbit. The proposed MAGLEV platform is said to be a type of highly advanced and very powerful celinoid that will allow the space vehicle to go at supersonic or even hypersonic speeds, and then will be assisted with booster rockets upon launch at the end of the MAGLEV rails.


It is undeniable that the celinoid has helped advanced our civilization and yet only few people know about them. They are like the unsung heroes of the electrical industry – very useful simple machines yet are often taken for granted by the masses. But maybe it’s due to the fast-paced nature of our civilization that also makes us forget or take many things for granted. Still it would be a great thing to see what celinoids could be used for in the distant future.