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What is a reed switch, and which magnets operate them?

Reed_switch_featured

A reed switch is an electromagnetic switch used to control the flow of electricity in a circuit. They are made from two or more ferrous reeds encased within a small glass tube-like envelope, which become magnetised and move together or separate when a magnetic field is moved towards the switch. The switch effectively works like a gate, or a bridge, in an electric circuit so when the two reeds are in contact, electricity can flow around the circuit operating a device. Unlike mechanical switches they do not require something or someone to physically flick them on or off, they are controlled completely by invisible magnetic fields! Continue reading

What are eddy currents and why do they make a magnet fall slowly through a copper pipe

Neodymium ring magnet on 15mm copper pipe

 

Magnets are fascinating – there are many things about magnets for which the only explanation seems to be magic! The best place to find out about magnet-related phenomena is of course here, on our blog – and YouTube. The most viewed videos showing super-strong magnets falling through copper pipes alone have amassed an incredible 8 million views and counting.

What you are seeing in these videos is of course a demonstration of eddy currents in action. Here we will explain what is going on.

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Animal magnetism – Nature’s own satellite navigation system

Migrating sea turtle swimming

The Earth produces its own magnetic field, which emanates from its magnetic inner iron core. On the Earth’s surface the magnetic field is extremely weak compared to the permanent magnets used in many every day appliances. At the magnetic poles the Earth’s magnetic field is approximately 0.7 Gauss compared to the Gauss value of a relatively small 10mm diameter x 5mm thick N42 neodymium magnet which can reach 5100 Gauss.

It is this magnetic field that makes a compass point north but for many species, the Earth’s magnetic field has a much more profound role…

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Heat-assisted magnetic recording – A new approach for data storage

hard disk drive

Ordinarily, heat and electronics aren’t the best of companions; even less unsuited partners are heat and some magnetic materials!

However, a new technology being developed by Seagate for the next generation of storage devices, known as ‘heat-assisted magnetic recording’ is breaking the convention. The technology is heralded as revolutionary and could significantly increase the amount of data that can be stored on a hard drive by increasing storage density.

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