Sparkfun Electronics TOL-11296 Technical document

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12V/5VPowerSupplyHookupGuide
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Introduction
The 12V/5V (2A) power supply is great for powering a microcontroller and an LEDs. In this tutorial,
we will replace the power supply’s molex connector with two male barrel jacks adapters.
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PowerSupply‐12V/5V(2A)
TOL‐11296

RequiredMaterials
To follow along with this tutorial, you will need the following materials. You may not need everything
though depending on what you have. Add it to your cart, read through the guide, and adjust the cart
as necessary.
Wishlist for 12V/5V Power Supply Hookup Guide SparkFun Wish List
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Product
Power Supply - 12V/5V (2A)
TOL-11296
Power Cable - 7A IEC C13
TOL-11299
DC Barrel Jack Adapter - Male
PRT-10287
DC Barrel Jack Adapter - Female
PRT-10288
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Tools
You will need a soldering iron, solder, general soldering accessories, and the following tools.
DigitalMultimeter‐BasicHook‐UpWire‐Assortment(SolidCore,22AWG)
TOL‐12966PRT‐11367
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SolderLeadFree‐100‐gramSpoolFlushCutters‐HakkoDiagonalCutters
TOL‐09325TOL‐11952TOL‐08794
WireStrippers‐30AWG(Hakko)WellerWLC100SolderingStation
TOL‐12630TOL‐14228

HardwareOverview
The power supply’s pinout is shown below. The connector’s molding will have numbers associated
with the output to help identify the connection. You will also notice that the connector is polarized
with the two chamfered corners.
PinoutTable
Warning! Depending on the manufacturer, the colors of the wires inside the sheath may vary. Make
sure to test the connection with a multimeter before before connecting to a load and powering your
circuit up!
The following table describes the molex connector’s pinout and what color the wire may look like.
MolexPinout 12V/5VPowerSupplyNotes
1+12V"Red"
2N/CMayNotBeNotConnected
3GND"Yellow"
4+5V"Black(orWhite)"

HardwareHookup
Cut the cable about 1-2 inches from the molex connector.
Cut into sheath with the flush cutter. Pull it back just enough so that you have enough room to work
with the wires. Be careful not to cut yourself!

Strip the power supply’s three wires. The wires are stranded so feel free to tin the wires by adding
solder to the tips.
Then cut and strip a piece of hookup wire. Solder it to the ground wire.

Braid the wire and insert into a barrel jack connector. Secure the wires in the screw terminal with a
Phillips head. Feel free to add some heat shrink or electrical tape to the connection at this point.
Note: Using screw terminals is one method of modifying the 12V/5V power supply. For a more
secure connection, try splicing the wires to a polarized connector and adding heat shrink to your
connection. You can also use a USB connector for the 5V side depending on your personal
preferences.
TesttheOutput
Power the power supply and test with a multimeter to verify the voltages. Usually power supplies are
center positive so make sure that the wires were inserted correctly. Adjust as a necessary for your
system.

LabeltheOutput
Using a Sharpie, clearly label the barrel jack connector’s voltage relative to the output. Feel free to
add an additional barrel jack when not in use.
PowerYourCircuit!
Connect the power supply to your circuit and power it up! I personally use the power supply as a tool
for basic testing. Usually the 12V side is connected to an Arduino’s barrel jack. The 5V output is
used for more power hungry loads such as the the RGB LED Matrix or a few meters of addressable
(WS2812B, APA102, etc) LEDs.
Arduino Mega 2560 and 32x64 RGB LED Matrix Powered by the 12V/5V Power Supply

Troubleshooting
Certain power supplies have a lot of noise. While 12V/5V power supply works great with a
microcontroller and a LED strip, it may not work as well when you attach a capacitive touch sensor
to the system. The power supply lacks proper filtering and causes the potentiometer to have a lot of
latency. You can try to add additional circuitry to fix it since the current power supply has a lot of
noise. However, it would be easier to use two separate power supplies or a more robust power
supply such as a Meanwell.
Example PWM Lighting Controller from the Touch Potentiometer Hookup Guide
ResourcesandGoingFurther
Now that you’ve successfully got your 12V/5V power supply up and running, it’s time to incorporate it
into your own project!
For more information, check out the resources below:
Molex Connector Pinout - Pinout of one power supply. Remember, wire color may vary
depending on your manufacturer.
Wikipedia: Molex Connector
SparkFun Eagle Libraries - Check out the Eagle part for the molex connector in our libraries.

Need some inspiration for your next project? Check out some of these related tutorials that uses the
12V/5V (2A) power supply.

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Make bright, colorful displays using the 32x16, 32x32, and 32x64 RGB LED matrix panels. This
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Getting started guide for the Large Digit display driver board. This tutorial explains how to solder the
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Arduino.
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How to crack an unknown safe in under an hour.
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https://learn.sparkfun.com/tutorials/12v5v‐power‐supply‐hookup‐guide5‐22‐18