Hey! Stop walking in front of my television's magnetic field, Im trying to watch here!

(What is the function of magnets in television?)

(Sarah And Elvira, Period 3)
imagesCAKVN9T3.jpg
An old television

Have you ever walked directly in front of a television screen while someone was watching a show, just to annoy them? Yeah, we do that all the time and we know you do too. It's almost like you're magnetically dragged to the screen. Haha. Anyways, magnets are used in many different ways in order to get a television to work for your benefit of entertainment. It's how the nice picture shows up on the screen, or how the sound comes out of the speakers, or how you're so magnetically attracted to it that your procrastination is a north pole and the television is it's south pole. However, we're going to focus on how the nice picture shows up on the screen, through the attenas on the television to another prank you can pull on your siblings, that is, if you have a television from way back in the day.


Antennas on a television are like small pieces of wire that have small amounts of AC current flowing through them. The magnetic field that surrounds the antennas is what allows antennas to have AC current flowing through them. Even though the current is low, it still provides enough power to turn on your television. The television works properly when radio frequency (produced by the magnetic field) moves across a recieving antenna and into the television

tv.jpg
Antenna from a television
digital-tv-antenna.jpg
A modern antenna
TV_Dish_Satellite_Antenna.jpg
A sattellite antenna


In modern times, antennas cannot be found on the top of the television, where they once were located. Now antennas can be found on the tops of roofs, their shapes and sizes vary slightly from roof to roof, but most antennas have the same overall structure. The placement of the antenna on the roof is so the antenna can easily pick up radio frequencies. There are many different antennas, ranging from satellight to digital to just plain antennas. The dipole antenna is the simplest of all the antennas and you can even make a similair one at your own house!



Antennas are made from metals that are good conductors of electricity. One popular metal that is used for antennas
flexible_antenna.jpg
A flexible liquid metal

is steel, partly because of its cheap price and also because it gets the job done. Recently, however, scientists have been experimenting with new materials, one of which is liquid metal, as shown to the right. This antenna does not break easily, as the regular metal antennas do. Also it has a great ability of healing itself, even if it is partially cut with a blade, once the blade is taken away the metal fuses together again. Most importantly, the liquid metal lets the magnetic field transmit radio frequency. Scientists are currently working hard on developing these new antennas into safe, non leakable material.


Another way magnets were incorporated into televisions was back when people were using CRT TVs. CRT stands for Cathode Ray Tube, which all televisions used before plasma or LCD screens. A Cathode Ray Tube consists of electron beams which are guided by moving magnetic fields, that provide the screen to light up with an image. The magnetic field is generated by coils
600px-CRT_screen__closeup.jpg
A CRT screen with colorful beams.
as well as electical circuts in the tube, which allow the magnetic field to cause the beams to be bent by magnetic deflection. The screen on the television consists of a metal grid which can become magnetized. This is why when a magnet was placed by a television back in the day, the picture on the screen would become distorted, since it would interfere with the beam. Today's televisions consisting of plasma or LCD screens do not have this feature of beams and magnetic fields built into them, therefore this trick does not work with them. When armed with a strong enough magnet, one of the beams could become damaged enough that a hole is made in the magnetic field and there is a black dot on the screen.


This video demonstrates what would happen if a strong magnet was placed by a CRT television screen.
This is how you can make your own antenna. Go ahead, you know you want to!

RESOURCES: