"Why Do" Wednesday - Why Do Electronics Cables Have Those Bulge Things?

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Ok, this is going to get a bit scientific for a bit, but will try to keep it on the down low!  So first of all these little bulges are called Ferrite Beads.  They are basically a hollow cylinder made out of an iron composite material (iron, manganese and zinc)...  They are found on most electronics cables.



This is what they look like inside the plastic mold...



So why do cables need these on there? Well, the answer is they are a filter.  There are two reasons to have them.  The first is to keep electronic noise from radiating into other devices or the air.  The second is to keep radiated noise from getting into your device.  So what does that all mean?  Think of it this way...   If you go out on a sunny day and it is too strong for your eyes, you put on a pair of sunglasses.  This essentially blocks certain parts of light and make it easier on your eyes.  

Now even though this isn't the same thing, it can give you an idea of why they are needed.  All around us there are radio waves buzzing around.  What a ferrite bead does is filter those waves out so that your cable doesn't pick them up like a radio antenna and inject that noise into the system.  This could cause malfunctions.  In the fist case it also keeps the noise a system generates from having all the electronics flipping bits and electrons flowing through circuits from radiating out your cable into other devices, but more importantly radiating into the air and violating FCC regulations.


The FCC regulates all this stuff from Bluetooth headsets, phones, TVs, stereos, computers and all other electronic devices cannot radiate this noise and interfere with other devices.  So they set limits on how much can be radiated out.  These ferrite beads are needed many times to meet those regulations.  

Although sometimes the FCC is a little over bearing, some regulation is good since you don't want your cell phone call interrupted because your doing your laundry.  Also this is why they make you put your phones in airplane mode when flying so that it doesn't interfere with the airplane controls.  This rule has been eased over the past years though.  Now you can at least have WIFI on most flights. :)

So to summarize, these little bulges are ferrite beads needed to filter out electronic and radiated noise to keep the government happy and your electronic devices running smoothly.

#RookieGuru
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