Let’s see how to convert a computer power supply to a benchtop power supply using an ATX breakout board. This is a cheap and easy DIY lab bench power supply with 12V, 5V, 3.3V or adjustable DC output that you can use to power any electronic devices. No need to break open the power supply enclosure and no soldering required. All you have to do is connect it!
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Why should you use an ATX breakout board?
One of the most useful tools for hobbyists passionate about electronics is a benchtop power supply. It uses alternative current and convert it to provide DC current to power any electronic device.
Since a bench power supply can be relatively expensive to buy, I personally prefer to use this homemade bench power supply instead. This is a cheap and easy way to repurpose an old computer power supply into a lab bench power supply. If you don’t have one already, you can always find a brand new one for less than $50. Let’s now see the different methods to convert an ATX power supply to a variable benchtop power supply.
How to convert an ATX power supply to a bench power supply?
There are 2 main ways to convert an ATX power supply to a bench power supply.
The first method is probably the most fastidious and requires good electronic skills. This method has been extensively covered in several posts and videos, so I won’t go into details here. It involves opening the power supply to rewire everything including a resistance load, as well as drilling its case to fix the binding posts that will be used as connectors. I honestly don’t recommend this method unless you know exactly what you are doing, as computer power supplies can deliver a lot of current and represent a big risk of electrocutions.
Check this ATX breakout board power supply adapter on Amazon
But don’t worry; there is also a much easier and cheaper way to convert an ATX power supply to a bench power supply simply by using an ATX breakout board!
What is an ATX power supply breakout board?
An ATX breakout board is a small circuit board integrating several components. You can plug it to any 20 or 24 pin ATX power supply such as a computer PSU. The ATX breakout board will provide DC current. In addition, there are several binding posts on the breakout board providing different voltages (3.3V, 5V, 12V or variable voltage). Therefore, it is perfect to use to power any DC electronic devices such as microcontrollers, motor drive, Raspberry Pi, LED light strips, etc.
How to use an ATX breakout board to convert an ATX power supply to a variable benchtop power supply?
An ATX breakout board can also be used to convert any ATX power supply to a variable benchtop power supply. Such breakout boards have an integrated voltage regulator knob and a LED screen, which indicate the supplied voltage. It is therefore super easy to adjust the voltage output by selecting the right value using the knob.
These ATX breakout boards are such a great buy when you consider how cheap they are compared to buying a classical lab bench power supply. Furthermore, these breakout boards are so easy to use and they are perfect for amateurs looking for a cheaper alternative for a benchtop power supply.
Best ATX breakout boards
Electronics-Salon 24/20-pin ATX DC Power Supply Breakout Board Module
This is a really nice breakout board from Electronics-Salon. It is rated 4.8 out of 5 on Amazon with over 300 reviews. This breakout board is easy to use and can convert any 20 or 24 pin ATX power supply into a bench power supply. All you have to do is plug it!
This breakout board is well designed and provides everything you need for the conversion of the ATX PSU to a lab bench power supply. It has a latching button switch to power ON/OFF. The breakout board also has an internal resistor load, which is required for the ATX power supply to function.
Click Here to See this ATX Breakout Board from Electronic-Salon on Amazon
One of the main advantages of this ATX breakout board is that it uses high quality screw terminal blocks. These 2.5mm jack connector type can accommodate wire ranging from 26 AWG to 12 AWG. Furthermore, the board has a rated voltage of 400V and a rated current of 24 Amp.
With its high current rating, the breakout board from Electronics-Salon is perfect to provide DC power for electronic devices requiring high amperage. For example, this ATX breakout could be used to power LED strips, motors, Peltier modules or 3D printers.
There is also many screw terminal blocks on the breakout board that can provide 3.3V, 5V or 12V DC power. If you need to supply any other voltage you can create a variable power supply using a LM317 module. Check my previous post about the LM317 voltage regulator or my LM317 video if you want to learn more about adjustable DC output.
The overall dimension of this breakout board is 3.74 x 3.39 x 1.46 inches. In addition, this board has a 5V connector with a stand-by mode (SB), which means that this port will continue to provide power even though the power supply is turned off. This is useful for electronics that needs to be powered constantly such as a router or else.
In summary, this is a really good ATX breakout board that can provide high amperage current. The only downside of this board is that it is not supplied with a protective case or enclosure. I would therefore recommend putting it using an old DVD case to isolate the binding posts and prevent power shortage.
Pros:
-Rated for high voltage and amperage (400V and 24 Amp capacity)
-Many high quality screw terminal blocks
Cons:
-No adjustable voltage output
-No protective case or enclosure provided
SuperPlus ATX Power Supply Breakout Board and Acrylic Case Kit with Adjustable Voltage Knob Supporting 3.3V, 5V, 12V and 1.8V-10.8V Output Voltage and 3A current
The SuperPlus ATX breakout board is probably the best one you could get. This breakout board is an all-in-one solution that provides everything you need to convert an old computer PSU to a benchtop power supply.
Check this ATX Breakout Board from SuperPlus on Amazon
This ATX breakout board supports 3.3V, 5V, 12V and also a 1.8V-10.8V adjustable output voltage (ADJ). The output voltage is shown on a small LED screen and you can adjust it easily by turning the adjustable voltage knob.
Furthermore, this breakout board is polyvalent and offers many connector types such as an USB port supplying 5V. The voltage output terminals of this ATX breakout board are also compatible with banana plug connectors. This is really useful if you want to use alligator clips to easily connect it to any electronic device.
These Alligator Clips with Banana Connectors can be Used with the ATX Breakout Board
The only minor downside of this ATX breakout board is the rated current capacity. This ATX breakout board can only supply 3 Amp or 24W. Nevertheless, this board is perfect to use with small electronic appliances drawing less current. In addition, this ATX breakout board has a reset protection.
The overall design of this board is well thought and this is by far the best one on the market. The breakout board is supplied with an acrylic case to protect it. There are also magnets at the bottom of the board, which makes it very convenient to fix it to the ATX PSU.
In conclusion, this ATX breakout board is the best option for a benchtop power supply with adjustable voltage. The USB connector and the banana plug compatibility make it very convenient to use for electronics that require less than 3 Amp or 24W power. I would highly recommend this ATX breakout board!
Pros:
-Adjustable voltage output with knob and LED screeen(1.8V-10.8V)
-USB port
-Can be used with alligator clips
-Acrylic protective case
Cons:
-Low current capacity 3 Amp or 24W
I hope that you found it guide useful. Don’t forget to check my previous posts to see how I used it to build a homemade thermoelectric Peltier cooler or a homemade humidifier using an ultrasonic mist maker.
Check this digital oscilloscope from Siglent Technologies on Amazon
Warning and disclaimer
ATX PSU can deliver enough current to cause serious injuries or death. I am not responsible for any accidents or damages. Feel free to use the affiliated links presented on this page. The prices are the same, it is anonymous, and this way you can support the making of these videos.
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