How to Make a USB Breadboard Power Supply




About: Check out my YouTube channel, for similar projects.

I purchased many USB breadboard power supply from market but none of them fit on my bread board. Reason being non standard dimensions of breadboard. Holes are 2.54 mm apart, but total size is variable.

Hence I decided to make one by myself which could fit all my breadboard.

It was really simple when I realized that my computer gives me regulated 5V.

Step 1: What All Things You Will Need?

You will need following things to make this small supply-

  1. One USB type A male connector
  2. small piece of general purpose circuit board
  3. few 2 pin male and female connectors

If you are confused go for images.

Step 2: Bit of Theory

We need to make a bit of mechanical and electrical considerations.


There are 4 pins in a USB type-A male connector, spacing between them is not uniform, look at the attached image. spacing between pin number 1-2 is 2.54 mm, 2-3 is 2.04 mm, 3-4 is 2.54 mm. Now standard pitch in General purpose Circuit Board(GCB) and breadboards is 2.54 mm.

Connector wont fit exactly or directly in your GCB , we will have to stretch them a bit.


pin-outs- As you can see in attached image outer most pins are 5V and GND, and inner pins are D+ and D-. we will be using 5V and GND pins.

Ok, you get 5V but how much current. For USB 1.x and 2.0 current is limited to 500 mA, for USB 3.0 its 900mA. So if your circuit under test demands current that is less then this ratings, you will never run out of batteries. Supply voltage can vary from 4.75 V - 5.25 V in case of USB 1.x and 2.0, 4.45 V - 5.25 V in case of USB 3.0.

Step 3: Assembly Time

Just connect 5V pin and GND pin to respective jumpers using solder. I have attached images for your reference. Just look at them if you are confused.

Step 4: Testing

Just hookup your multi-meter to breadboard where you can probe the output of our homemade supply. If you get voltage in the range of specification of USB you are ready to go. Else check for Short and Open as these are the only two faults that can happen. If its Short touch the solder it feels hot.(I accidentally did it while making this!!!!).

OK, so finally you have a handy tool which will give you 5V with out any problem (Of course you need a PC or a Lappy).

Thanks for reading, I am also attaching a link to my video for the same feel free to have a look.

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    11 Discussions

    Kurt E. Clothier

    3 years ago

    Using the computer USB port is a great source for small circuits and such. One great method I have found is to just cut apart an old USB charging cable and solder male headers onto the VCC and GND lines. Then you have a longer cord to reach from the ports to your circuit.

    Another note, connecting multiple pads on a circuit board (perf board, in your case) just using solder isn't typically a good idea. It isn't bad for small signals, but is definitely not a good practice for power transmission because the solder doesn't conduct electricity that well. Another quick trick - cut the leads off of a components (like a cheap resistor), using the metal pieces to connect your components on the board. Just use solder to hold it to the board.


    3 years ago

    usually USB ports on pc's and laptops can only supply 500mA current, if the current draw exceeds that limit their is a chance of burning out the voltage regulator for USB ports on motherboard.

    3 replies

    I guess I should mention, this doesn't necessarily apply to powered USB hubs like what is used in this guide.


    Reply 3 years ago

    Its great that you have brought this point to discussion but I think I have mentioned this point in one of the steps which was on electrical specification. (USB 3.0 has current limit of 900 mA).
    And I think these voltage regulators have short circuit protection so no need to worry.


    3 years ago

    Cool idea! I'll do it for sure. I'll leave you a message then.

    1 reply

    3 years ago

    How does this attach to something that needs power?
    What is a lappy?
    Is there a risk of a shock from the exposed circuitry?

    2 replies

    Reply 3 years ago

    USB male goes in your PC or Laptop's(lappy -sorry for creating confusion) USB female jack and connectors(male and female) that we mount on general purpose board goes to your breadboard, where you connect your circuit under test.

    Thanks JohnR48, for answering question on exposed circuitry and as he said be careful not to short. I think it would be better to make a casing for it, will give it a professional look.


    Reply 3 years ago

    A lappy is a laptop. It is only five volts, so no chance of electrocution, although you could short it if you were not carefully.


    3 years ago

    What a great idea! This could be quite useful.