The psychic
who senses
invisible magnetism.

Magnetic Sensors

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#09

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I respond to magnets and other magnetic forces!
I can measure the strength of magnetism!

The Power of Magnetic Sensors

For on and off switches!

These electronics can also act as switches using their magnetic power.
For example, laptop screens turn off when you close them. This is because they turn off when they sense a magnet in the display gets close to a magnetic sensor in the keyboard.
They turn the screen on when you open them because they know the two moved apart, too.
They turn on and off with magnetism!

An illustration of magnetic sensors at work. There is a magnet in the laptop screen, and a magnetic sensor in the keyboard. The sensor turns off when the laptop closes and the magnet approaches the sensor.

The Secret of the Power of Magnetic Sensors

The strength of the magnetism tells us how much electricity there is!

The amount of electric current that goes through a magnetic sensor changes with how strong its magnetism is.
More electric current flows through it when the magnetism is stronger, and less when it is weaker.
These sensors help switch things on or off when other electronics take in the electric current.

An illustration showing magnetism strength and electricity flowing. The stronger the magnet (and magnetism), the more electricity, and the weaker the magnet (and magnetism) the less electricity.

Friends of Magnetic Sensors

Types of magnetic sensors

Some magnetic sensors can tell the north and south poles of a magnet as well as how strong it is!

Trivia

What are the units?

We measure magnetism in units called “T” (teslas). This can be in forms like “10 mT” (meaning “millitesla.” Milli means one one-thousandth), and higher numbers mean stronger magnetism.
Stronger magnets also have higher numbers, and the same strength of magnet has a higher number closer up.

Think it out!

QUESTION

The answer is 1, a weak magnet far away.
Electricity doesn’t like to go through sensors when the magnetism is weak.
Weaker magnets and magnets farther away will feel weaker to magnetic sensors.

Find the Magnetic Sensor!