Adjustable Breadboard Power Supply

Another breadboard power supply designed by Seeed Studio. it can directly takes power from DC wall wart and outputs a selectable 5V or 3.3V regulated voltage.

Compare to other breadboard power supply designs, this one provided mini-USB port like the seeeduino , you can toggle the switch and select your power source. (USB or dc jack).

With this board, you can send power to both power lane of the breadboard, and each side has a on/off switch.

Model: TOL123D3P


Application Ideas


The warnings and wrong operations possible cause dangerous.


It is the schematic, the circuit about Eagle resource like .pdf should linked here in order to avoid memory exhausted.


Key Specification

Specification Conditions Min Typ max Unit
Input voltage 5.0 6.5 12.0 V
Output Voltage Channel 3.3V 3.235 3.3 3.365 V
Channel 5V: 10mA≤IOUT≤1A, 6.5V≤VIN ≤12V 4.9000 5.0 5.100 V
Current Limit VIN-VOUT=2V 1.2 1.35 A
Ripple Rejection f=120Hz, COUT=22μF Tantalum,VIN-VOUT=3V, IOUT=1A 50 70 dB
Temperature Stability 0.5  %

Pin definition and Rating

Mechanic Dimensions


Hardware Installation

  1. Align the polarity of pin header to breadboard. (Usually Red for +, Blue for -)
  2. Plug the supply board to breadboard completely.

Now you may de-activate power by the two jumpers, or adjust the vertical switches to select different voltage. The horizontal switch is used to select JST 2 pin or mini USB cable as input.


Includes important code snippet. Demo code like :

Demo code
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The projects and application examples.

Bill of Materials (BOM) /parts list

All the components used to produce the product.


Please list your question here:


If you have questions or other better design ideas, you can go to our forum or wish to discuss.

Version Tracker

Revision Descriptions Release
v1.0b Initial public release Nov 16, 2009
v1.1 Initial public release Oct 10, 2011

Bug Tracker

Bug Tracker is the place you can publish any bugs you think you might have found during use. Please write down what you have to say, your answers will help us improve our products.

Additional Idea

The Additional Idea is the place to write your project ideas about this product, or other usages you've found. Or you can write them on Projects page.


How to buy

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See Also

Other related products and resources.


This documentation is licensed under the Creative Commons Attribution-ShareAlike License 3.0 Source code and libraries are licensed under GPL/LGPL, see source code files for details.

External Links

Links to external webpages which provide more application ideas, documents/datasheet or software libraries

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