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Copyright:  Mike Sillett


1. Intro
2. Materials
3. Tools
4. Procedure

photo of two power adapters of two different voltages, current rating and connector types.
Two of the AC/DC Power Adapters used to make one Customized Adapter.

1. Intro

Power Supplies, AC/DC Converters, Power Brick, Plug-In Adapter, Wall Warts, Power Adapter, are just a few of the names used to describe those sources of DC power that we use to run some of our electronic / electrical devices.
They're great to have when you wish to save cost on battery purchases. I know that my digital camera goes through batteries like you would not believe. At least when I am using the camera at home I can use the power adapter and save on the batteries.

Quite often the adapter outlives the devise it powered and it is relegated to the junk draw, given to a charity for resale or just thrown away. I see them quite often in various thrift stores, garage sales and flea markets selling anywhere from .25 cents to $1.50.

When you look at the specification that is usually inscribed somewhere on the adapter it almost always seems that there is some requirement not met to enable you to use one of those inexpensively priced adapters for some electronic / electrical device you need one for. Eventually you end up buying one at high cost which can be anywhere from $15.00 to $30.00 with S & H costs.

This tutorial aims to help you utilize some of those discards / bargains by cannabalizing parts from a couple of adapters to make one that will power your devise.
The adapter I used to power the camera to take photos for this tutorial cost me .50 cents ( .25 cents for each adapter ).

2. Materials

Two AC / DC Adapters, each having a specific attribute that is required or desired, or both ( such as Tip Polarity, Voltage, Connector Size, Connector Configuration, Electric Current Output, Physical Size and Weight )

photo of two power adapters of two different voltages, current ratings and connector types.

Two power adapters.
One has the connector style and size needed. The other has the correct voltage, current and polarity requirements.

3. Tools

Soldering Iron ( optional ),
Electrical Tape,
Razor blade or sharp knife,
Blank labels,
Continuity checker,


As noted above, one of the requirements is the connector configuration you will need so it is important to note what the socket on the device looks like. Here is an example of a socket on the camera:

photo of a socket on a device that needs a matching type connector plug.

Look at the socket on the device and you will see either a ' hole with a little pin ' inside ( like shown above ) or 'just a hole'.

If it is just a hole than a straight connector of the type shown below may be needed:

photo of straight connector style.

This is the type of connector needed for ' just a hole ' type plug. Polarity is indicated by + or -
In this example the connector is a + tip type. It could have just as easily been a negative tip type.

If the plug has a little pin inside then a 'sleeve' type connector is needed, as shown below.

photo of sleeve type connector.

This is the type of connector needed for ' hole with a little pin ' type plug.
In this example the connector is a + tip type. It could have just as easily been a negative tip type.

However, before you start cutting wires to start your customizing project it is a great idea to make sure the ac/dc adapter does work.
Plug it in and put your multi-meter to work. Take note of the polarity symbol on the adapter. You will see some inscription that looks like either of the below illustration:

photo of illustration demonstrating the polarity symbols often found on AC/DC Power Adapters and Devices.

The illustration demonstrates the two different 'polarity symbols' that can often be found imprinted on Power Adapters and Chargers.
it is very important to make sure the polarity is correct.

An easy way to interpret the symbols is to visualize the symbol in two parts:
One part will always be a C with horizontal line attached.
The other side of the symbol will always be a O with a horizontal line attached.
The O always goes into the C Therefore the C is always the device and the O is always the connector.

For example, if the upper symbol appears on the adapter, you will place your red ( + ) multi-meter probe inside the sleeve of the connector, or if a straight style connector, on the tip.
The outside of the connector ( the sleeve ) is the negative so the black ( - ) multi-meter probe will be applied to the outside.
If it is a straight type connector rather than a sleeve type then the rear of the connector is the negative - see photo below:

photo demonstrating how to test a 'Tip Positve' connector on a power adapter.

Demonstrating the testing of a 'Tip Positive' sleeve type connector.

You actually need to check only the adapter you intend to use to power your specific device. Remember, the other adapter is being cannibalized only for the connector plug so the only thing we will concern ourselves with, once the connector plug is cut off, is that there are no internal wire breaks inside the cable near the juncture. That is usually a critical area and oftentimes is the cause of the adapter no longer working, or working sporatically.
We'll need only to do a continuity test of the connector plug that we cut off and label the wires for polarity.
That's another step described further down.

Now that we know the adapter we intend to use is actually a good working adapter and the other adapter has the correct connector plug type, size, we are ready to do some cutting.

First, we want to make sure which of the two molded wires, or wires within a cable, are the negative and positive. Sure, we know on the connector plug end which is which, however, under the insulation you won't know yet which wire is connected to the postive side and which the negative.

If you have a cable that does not have wires with different color coding on them then the way to strip insulation is to carefully separate the wires about 6 inches above the juncture and then carefully remove the insulation from each wire ( use a sharp razor and be slow ) you can then use the multi-meter to check the polarity.

Sometimes the wires are marked / color coded differently. If that is the case you can just cut the cable 6 or so inches above the juncture, separate the wires, strip the insulation and then do a polarity check.
Do this to both of the adapters.

photo demonstrating how to strip the insulation so the wires can be checked for positive and negative.

Exposing the copper under the insulation so the polarity can be checked AT THE WIRES.

Checking wire polarity under insulation

After the wires are stripped of insulation use your multi-tester on the power adapter OR continuity checker on the cut-off connector plug to determine which wire of the set from either is the positive. The other then will be the negative.

Using the multi-meter to check polarity of the power adapter wires.

As already stated, sometimes the cables are differently colored ( like photo below ), sometimes not.
If they are, use that to your advantage by noting, after the polarity check is done on either the adapter side wires or the connector plug wires, to label the corresponding color coded wire on the other end of the cut cable.

photo showing the cut wires of the plugged in power adapter being tested for polarity with a multi-meter.

The power adapter in this photo is plugged into the wall socket.

The multi-meter's needle will register a positive voltage if the red and black probes are placed on the correct stripped wires. Just do it and see.
If the multi-meter probes are put on the wires in the incorrect order the multi-meter's needle will go backwards.

This photo demonstrates that the red ( positive) probe has identified the striped color-coded wire as the positive wire because the needle went forward.
I will now label the striped wire as POSITIVE for future reference.

Using a continuity tester to check polarity of the connector wires.

If you do not have a multi-meter you can use an inexpensive continuity checker to figure out from the 'connector plug side' of the cut-off cable which wire of the two is the positive and which therefore is the negative.

Continuity checkers are used in circuits where there is NO power so do not plug anything in.

photo showing the cut wires at the connector end being tested for continuity and polarity.

This photo demonstrates how you can determine polarity using the cut-off cable of the connector end.

I do not have an inexpensive continuity tester so I am using the multi-meter as the continuity tester.

One probe is attached to a wire ( the black one in the photo above but it does not matter which is attached )
the other probe then is touched to the connector's sleeve or inside the tip. One of the two will cause the continuity checker to light.
Whichever it is make a note of it.

In the photo above I have determined that the bare wire wrapped around the black probe corresponds to the sleeve of the connector. From the power adapters inscriptions it is noted that the power adapter is a 'positive tip' type adapter so now I know that the bare wire is the negative and the white wire therefore is the positive. I will label those wires for future reference.

Testing the wires for loose connections under the thick juncture
before actually putting the two ends together.

Take the connector plug's wires that are stripped of insulation and temporarily twist them together. Now use your continuity tester or multi-tester and touch one of the probes to the tip and the other probe to the sleeve of the connector. It does not matter which touches which. We just want to see that a circuit is there that will register on your continuity tester or multi-tester.
Move / jiggle the juncture area around a bit to make sure there are no broken wires inside, under the insulation. Moving it about should cause nothing to change on the continuity tester or multi-meter.

photo showing the wires at the connector end which are spliced together and then checking entire connection for continuity.

Continuity check of the Connector wires and connector.
I used a blue thumb tack that has a thin shaft which fits inside the 'tip' of the connector because my multi-meter probe would not fit inside.
I could have used a thin piece of wire to stick inside but the tack was handier.

Now that we have checked the wires from the power adapter for proper function,
have noted which wire is positive and negative,
AND now that we know that the connector plug wires along with the parts of the connector plug have good continuity,
we just need to attach the corresponding wires together and solder or tape them up.


photo showing the approriate cable ends from 2 power adapters spliced together to make 1 usable power adapter.

The correct wires from each end have been spliced together.
It is always a good idea to double check everything before actually taping everything up.
The power adapter is plugged into the wall outlet. This photo shows the correct voltage & polarity so it is good to go.



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