March 19, 2010 AT 4:06 pm

From the forums… “BB Power Supply Pot Problem”

Pv36Y Series
Itsthemedication in the Adafruit forums writes -

I just put together the BB power supply, and only have 29 more to go. One reason for selecting this PS was for the adjustable voltage, i.e. I needed a STABLE 1.9 volts (don’t ask). Anyway, if anyone else is thinking about this excellent little board and needs a voltage greater than 3 I highly recommend ditching the single turn pot (very imprecise and possibly noisy as well) and replacing it with an 18 or 25 turn pot like Digikey 490-2914-ND (92 cents). The switched 3.3 and 5 volts work great by the way!

Bbpsup Lrg-3
Adjustable breadboard power supply – v1.0 – This project details the design of a very low dropout adjustable power supply. A good power supply is essential to electronic projects. While there are many existing designs for adjustable power supplies, this one makes improvements that make it more useful for hobby designs.

  • MIC2941 regulator has guaranteed 1.25A output
  • Low dropout, only 40mV – 400mV compared to 1.25V – 2.0V for LM317. This means you can use a wider range of output voltages including generating 3.3V from as low as 3.7V (such as 3 AA’s or a lithium ion battery)!
  • Short circuit and overheating protection
  • Input diode to protect circuitry from negative voltages or AC power supplies.
  • 2.1mm DC jack and terminal connector for voltage inputs
  • Two indicator LEDs for high and low voltages
  • Output selection switch to select from 3.3v, 5v and Adjustable
  • Onboard potentiometer for adjusting voltage from 1.25V up to within 0.5V of the input voltage. (20V max)
  • On/Off switch for entire board
  • Heat sink included

Breadboard and battery clip or DC power supply is not included, you can use any DC power supply with 2.1mm plug (we have a nice one in the shop). For design documents, instructions, parts list, etc. Check out the project webpage!

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1 Comment

  1. Wow – these look really awesome.

    Page 46 of the datasheet http://www.murata.com/catalog/r50e.pdf shows the pin spacing if any one want to know.

    And the mouser part number is: 81-PV36Y104C01B00

    Great find – I plan on using these as soon as I need to place another order.

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