SparkFun Electronics - Breadboard Power Supply 5V/3.3V

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Breadboard Power Supply 5V/3.3V

sku: PRT-00114

Description: A very simple breadboard power supply kit that takes power from a DC wall wart and outputs a selectable 5V or 3.3V regulated voltage. The .1" headers are mounted on the bottom of the PCB for simple insertion into a breadboard. Pins labeled VCC and GND plug directly into the power lines. The lone pair of pins have no electrical connection but help support the PCB.

There are two pins available within the barrel jack footprint. Any stripped +/- DC supply can be connected instead of the barrel connector. Board has both an On/Off switch and a voltage select switch (3.3V/5V).

Comes as a bag of parts kit and is easily assembled if you can follow the silkscreen indicators and have beginning experience with a soldering iron. You will need to read the resistor bands or use a multimeter to determine the resistor sizes.

Check out our Unregulated Power Supply Tutorial!

Kit Contains:

DC Barrel Connector (2.1mm center positive)
TO-220 Voltage Regulator (LM317 1.5A max current)
1N4004 Reverse Protection Diode
100uF 25V Capacitor
10uF 25V Capacitor
0.1uF 50V Capacitor
Red Power LED - High Brightness
2pcs SPDT Slide Switch
4pcs 0.1" Header Pins
2pcs 330 Resistor 1/6W
390 Resistor 1/6W
240 Resistor 1/6W
Bare PCB with Silkscreen Indicators
PTC resettable fuse

Documents: Schematic
Dimensions: 1.25x1.25"

Pricing

	172 in stock backorder allowed

$9.95	price
$8.96	10-99 (10% off)
$7.96	100+ (20% off)

	quantity

click on image to enlarge

Comments

44 comments

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	by Member #906 +1.2 \| Feb 6, 2006 at 12:03pm +0.21
This item worked out great for my usage. It went together in about twenty minutes and worked perfectly. For this price I don’t think you can beat this item.

	by mmmlinux +2.5 \| Jul 27, 2006 at 1:13pm +0.21
this is a very good product. I built it in about 25 minutes. and it works very well.

	by Joe +1.6 \| Aug 9, 2008 at 9:27pm 0
Does anyone know the value of the capacitor in the PTC slot? It doesn't show up in the schematics. ~thanks!

	by Nate \| Feb 12, 2009 at 12:40pm
The PTC is sold over here: http://www.sparkfun.com/commerce/product_info.php?products_id=8357

	by Maragnus +3.2 \| Sep 10, 2008 at 1:17pm +0.96
This is fantastic. First device I have ever soldered and had it done in about 45 minutes. But honestly, who's idea was that LED? If it were any brighter, I'd be blind.

	by Nate \| Feb 12, 2009 at 12:40pm
Sorry! They are called super-bright for a reason. A glob on hot-glue or a brushing of sand paper can knock down the intensity.

	by BB +0.83 \| Sep 10, 2008 at 11:35pm +0.55
You can also put a trim pot in place of the fixed resistors and voltage switch for a variable-voltage power supply, depending on your wall wart's output voltage.

	by PresidentOfAwesomeness +0.59 \| Feb 25, 2010 at 7:51am 0
I haven't had too much experience with trim pots, but I would think that they might wear out quickly if used for changing the power output, especially if you are working with many different systems. Maybe a regular linear pot instead?

	by c47334 +2.4 \| Sep 22, 2008 at 1:10am +1.4
AAHH MY EYES! IT BURNS! IT BURNS! Pro tip: Bend the leads on the LED by 90 degrees prior to mounting, so that the axis of the LED is parallel to the circuit board. That's what I would do, if I still had my eyesight. Excellent kit, otherwise. My compliments to whoever was responsible for the silk screen. The silk screen was very informative and greatly aided assembly.

	by Nate \| Oct 6, 2008 at 11:45am
Yea - sorry about that. The super-bright LED, is indeed super. You can opaque the leds with sandpaper, scotch tape, or some hot glue. There is nothing that says 'professional' like a pile of green glowing hot-glue.

	by kactus84 +1.6 \| Oct 18, 2008 at 12:28pm 0
I like the bread board power supply for getting projects up quick. It would be great if you also made a second power supply kit that had 3.3V and 5V outputs for imbedded use. One example is running a serial backpack LCD at 5V and Xbee at 3V. Logic and voltage complicate an easy project, fortunately your serial shifter makes quick work of the logic.

	by Matt-man +1.9 \| Oct 31, 2008 at 1:19pm 0
Great kit: inexpensive, easy to build, and lets you reuse a wall-wart that you might have laying around (I'm using one from a dead Netgear switch). The ability to select 3.3 or 5 volt output is a big plus, and I like the way it plugs directly into the breadboard.

	by c51683 +1.4 \| Nov 11, 2008 at 12:28pm 0
This was my first circuit board...ever. It took less than an hour after I figured out the biggest issue: My kit INCLUDED the PTC (or Thermister - see http://www.sparkfun.com/commerce/tutorial_info.php?tutorials_id=57) but NOT the .1 uF Capacitor. As of 11-11-08, the PTC is not in the wiring diagram (the USB version does show this). Anyhow, it worked first time.

	by FerQ +1.6 \| Dec 18, 2008 at 11:14am 0
In the picture you can see 4 capacitors, but the parts list contains only 3. Is the last one nessesary ? The free spot on the board reads "PTC"

	by RoboScience +2 \| Jan 18, 2009 at 12:34am 0
im trying to use this to power a tamiya gear box and to do so i need to get rid of the PTC. how can i safely remove it from the equation?

	by Nate \| Feb 12, 2009 at 12:41pm
I would just solder a piece of wire across the legs of the PTC - effectively shorting over it.

	by Davinci +1.1 \| Feb 1, 2009 at 8:46am 0
What should be the max input voltage from the wall wart? The max input voltage of the Lm317 is 40 volts but the schematic says it's max 10 volts. Does it get to hot when used with an 15 volt supply or can it be done?

	by Nate \| Feb 12, 2009 at 12:39pm
It depends on the current draw of your circuit. With a 15V input, and a 3.3V output, anything above 50mA is going to get warm. I'd recommend keeping the input to 7-12V if you need more than ~500mA.

	by RICoder +3.4 \| Feb 11, 2009 at 10:06pm +1.2
What's funny is that I designed myself a nice little switchable power supply in Eagle right after reading the tutorial and was going to get some boards printed. When I came to order some parts, I found this! Excellent little kit, really easy to assemble, and a great regulated power supply for projects.

	by EducaSoft +3.8 \| Feb 14, 2009 at 3:49pm +2.7
This kit was indeed a very nice one to put together. Thanks to the wonderfull silkscreen, the kit could be soldered together in no time and without having to look at the schematic or anything else. Congratulations on another fine product.

	by KirkS +3.3 \| Apr 17, 2009 at 9:26pm +2.7
Before tonight, I'd only used a soldering iron once - to make a patch cable. I built this kit in about 45 minutes and it worked perfectly the first time, giving 3.29V and 4.97V out with the TOL-00298 wall wart. Talk about a confidence builder! Thanks for the great kit!

	by EmilyP +2.2 \| Jul 8, 2009 at 1:35pm 0
I recommend using a 9V power supply with this kit. You will only get 3V (on the 5V setting) if you use a 5V power supply.

Exonerd

| Jul 11, 2009 at 11:40pm

This was one of the first kits I ever ordered from Sparkfun. I was intimidated by the lack of instructions at first, but the silkscreen labels are EXCELLENT. It worked the first time I powered it on, with 4.93 V and 3.24 V output. My only nitpick is that some of the resistor holes are a bit close together, so you have to be a bit careful not to over-do the solder.
One tip: To make the pins a bit more sturdy, I put a tiny bit of superglue on the underside of the board where they join the board.

	by KWC +1.8 \| Jul 30, 2009 at 3:37pm 0
Whose idea was it to put the input header holes off of the 0.100 grid?! My project has this board as a piggyback board on a 0.100 protoboard. Must have been that Arduino gremlin :-( I also wish that it was made more clear that the max input was 12V. I now need to scrounge a 50V cap for a 24V input.

AlanRoberts

+1.4

| Aug 3, 2009 at 6:00pm

I'll be putting together my breadboard power supply kit tonight.

I get bypassing the PTC if I want to be able to supply more current (and I've got a TO-220 heat sink kit in the parts box, I'll see if it fits), and doing something to avoid LED eye burnout :-)

The last time I remember looking at the LMx17 datasheet, I thought a 10uF bypass from the adjust pin to ground improved ripple rejection significantly. I don't see anything like that on the schematic. Is that an old technique that isn't necessary with modern LM317s, not done to keep cost and/or size down, or for some other reason?

	by RoHS \| Sep 16, 2009 at 11:58am
Used this part in this: http://www.flickr.com/photos/sparkfun/3926747868/

	by Brad A. +1.7 \| Oct 3, 2009 at 8:52am 0
What's the best way to get the pins straight on the output? I just warmed up the joint and used needlenose pliers to get them straight enough to insert, but there's got to be a better way.

	by iEEEj +1.6 \| Dec 2, 2009 at 12:03pm 0
the best way to solder the headers in is to put them in the breadboard first... although I dont like how this model hangs off the edge of the breadboard... I used a piece of foam to give it support

	by ricardo +1.4 \| Oct 17, 2009 at 9:24pm 0
First kit ordered, and first time I used a soldering iron .. No problems, kit went together easy, and worked the first time!. Thanks to the comments on here i replaced the super bright led with different one that doesn't blind!. Good job guys .. this is way fun!

	by ShortBus +1.5 \| Oct 26, 2009 at 10:36pm 0
Quick question: Looking at the schematic, it appears there are three smoothing caps: 100uF, 10uF, and 0.1uF. Why is the 100uF cap placed on the Vin side of the regulator, but the other two are on the Vout side?

	by NXTreme +5.2 \| Mar 31, 2010 at 12:06pm 0
Warning: Take this with a grain of salt The 100uf cap is to smooth out the bigger ripples before the regulator. Then, the regulator does its best to smooth the electricity flow even more. However, it doesn't do a good job a the higher frequencies of ripple so the smart engineer places to small caps a the Vout side to smooth it out even more. Thats my edgy-cated guess :D.

	by JWW +1.6 \| Nov 15, 2009 at 1:36pm 0
I built two of these power supplies this afternoon; the boards are nice quality, and the kits went together nicely.

	by anderson12 +1 \| Jan 6, 2010 at 4:58pm 0
Silly question, but what's the maximum current draw I can put through this on a sustained level before risking a burn out?

	by Tryforceful +1 \| Apr 16, 2010 at 2:16pm 0
The PTC fuse is rated at 250 mA at least...

	by Kha0stickler +1.3 \| Jan 12, 2010 at 2:13am 0
Just received mine today, took 15 minutes to assemble. Silk screen was really helpful and as a newbie to soldering it was a "cake-walk." Couldn't have been more pleased, with the finished product. Multimeter reads 5.05V and 3.28V well within the tolerances of this circuit.

	by TRON +2 \| Jan 18, 2010 at 12:17am 0
I just finished assembling and soldering mine tonight. Wasn't difficult at all and good practice for me. It was such a great relief when I saw that bright red LED light up when I plugged the 9 volt 350mA wall wart. I then checked the voltages and got 3.34 volts on the 3.3v and 5.12 volts on the 5v. It's all good. Thanks SparkFun for such a good kit. :)

	by mjr +1.5 \| Jan 20, 2010 at 2:15am 0
Will this power a WIImote.. which runs off 2xAA batts.. 1.5v or 1.2v recharges? I know sometimes a 1.5v bat will put off more, so I'm guessing that the WIImote can handle 3.3v fine. it seems similar to this design http://miskatonic-tech.blogspot.com/2009/12/usb-powered-nintendo-wii-remote-wiimote.html

DenkiGuy

+1.4

| Jan 20, 2010 at 5:05pm

I included one of these cool little power supplies in my Free Day order that never got through. I decided I wanted it enough to pay for it myself. I found the kit went together super easy and the output voltages were in tolerance. The only thing I don't like is that blinding LED. Super bright it is! If I knew it was going to be so bright I would have subsituted a surplus LED and saved the Super bright one for a flasher to use while riding my bike at night.

	by Maker Shed +1.5 \| Feb 22, 2010 at 11:24am 0
The kits we've received don't have all the included parts, but they do have the PTC in them, the 10uF capacitor is missing but seems to have an axial looking part instead, can you help?

	by Pearce \| Feb 22, 2010 at 1:09pm
Hello, If you can contact us at techsupport at sparkfun dot com, we will get you all taken care of. Thanks, Pearce

	by dereck72 +1 \| Mar 29, 2010 at 2:17am 0
will this run using a 9v LiPo rechargable battery? I was planning on running something had between 2.0-3.0 ohms resistance. Very much an electronics noob....but this might be perfect for an idea I got brewing.

	by RobertC. \| May 26, 2010 at 12:11pm
Yes, that should work fine. Powering it with 5v, i can get an ok 3v output, but only about 3.5 (when selecting 5v). So, 9v should be a good input for either voltage.

JamesW

+2.1

| Apr 19, 2010 at 7:57pm

Power Supply is very handy!
Product Suggestion: to complement this breadboard power supply. I would love to have just a small serial 1x8 LCD or as big as 2x16 if not too heavy I'm good with a couple of legs to touch my desk in order to get 2x16, setup like this power supply with the pins lined up for a Breadboard. So instead of using a single LED to debug programs with, I could use that same "Debug" pin to get real information from my programs.

hackmandu

+1.1

| Jun 7, 2010 at 10:35pm

Great kit for even an uber n00b! 3.34V and 5.08V output options using your 9V DC adapter. First time soldering, but I managed to keep the contacts separate even on some of the close ones. Definitely use a pen tip solder iron if you have one. Mine is an older beveled tip like a fat flathead screwdriver... not very easy for the small wire contacts. For the capacitors... anode (long pin if it has one) goes to square marking on PCB. Also, the negative hole is marked with a minus "-" sign (location for shorter of the two wires). First PCB experience, so I had to look this up.