Tech Tip: Label Your Power Adapters

If you’re anything like me… wait, I’m sure you’re nothing like me, fortunately for you…

Most people have many electronic devices laying around the house that are powered by big rectangular power adapters (affectionately known as “Wall Warts”).  But they tend to look alike, and if a device gets separated from its power adapter it’s hard to know what belongs to what.  So recently I started labeling my power adapter so I know which adapter goes with which device.

In addition to making it easier to mate an adapter with its owner, labeling also makes it easier to know which adapter plugged into a power strip to unplug.  When a power strip has 3 adapters in it, it’s usually impossible to know what device each one goes with if they aren’t labeled.

I use my electronic label maker to print labels.  (You do have a label maker, don’t you?  No?  Get one!) I usually include the manufacturer and name of a device on the label.  “Cell phone” or “Camera” isn’t descriptive enough, as surely someday you’ll wonder what cell phone or camera it was for.

Bonus Tips…

Once Separated, Now Reconciled

If you have separated a device from its power adapter, fret not… there are a few things you can do to match them back up again.  Or to find a suitable adapter that will work instead.

There are 4 things that need to match for a power adapter to work with an electronic gadget.  They are voltage, current, polarity, and connector. 

Most power supplies and devices will have information that looks something like the image above.  If both the adapter and device have all of this information, you’re in luck… you have enough information to know if it will work.

The above power adapter outputs 12 volts, can supply 500 milliamps of current, and has a positive tip (polarity).  To work with a device, the voltage and polarity of the adapter and device must match exactly.  If an adapter supplies too little voltage a device won’t work at all, or will behave erratically.  If the voltage is too high you’ll fry something.  Both the number and type of voltage must match (AC or DC). 

Tip: If a power adapter outputs AC voltage, there is no polarity so you won’t see the above symbol.  Just make sure the device requires AC voltage and that the numbers match up.

While AC adapters don’t have polarity, DC adapters do.  And you absolutely have to have the same polarity, or you’ll fry a device.  So look and make sure the location of the (-) and (+) are the same for the adapter and device.  Positive tips are more common than negative tips, but double check that polarity matches.

While voltage and polarity MUST match, the current rating is a little more forgiving.  If a device requires 300 milliamps (mA) of current, any power adapter that supplies a minimum of 300mA will work as long as the voltage and polarity match.  So if you find one that supplies 500mA and the voltage and polarity are correct, the adapter is a good candidate.

Once you find a power adapter that has the correct voltage, polarity, and can supply sufficient current, it’s time to check to see if the connector fits.  Try to plug it in.  If it fits, the adapter should work. 

	Device Requirements	Candidate Adapter #1	Candidate Adapter #2	Candidate Adapter #3	Candidate Adapter #4
Voltage	12 V DC	12 V DC	9 V DC	12V AC	12V DC
Current	300mA	500mA	250mA	300mA	200mA
Polarity	(+) Tip	(+) Tip	(+) Tip	(-) Tip	(+) Tip
Works?		YES!	NO!	NO!	NO!

Don’t Throw Them Out!

I actually keep the power adapters when I have to dispose of a broken device; they quite often come in handy later on for something else.  Just yesterday I purchased a new radio scanner that didn’t come with any power adapter at all.  Fortunately, I had one from a cordless phone that died a few years ago that matched perfectly.  I saved $25 by not having to buy a new one.