http://www.instructables.com/id/The-Radioshack%2c-Adjustable%2c-Breadboard-Power-Suppl/

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The Radioshack, Adjustable, Breadboard Power Supply.by kersny on June 27, 2007

Table of Contents

The Radioshack, Adjustable, Breadboard Power Supply. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Intro: The Radioshack, Adjustable, Breadboard Power Supply. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Step 1: The LM317 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Step 2: Calculating the Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Step 3: The Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Step 4: The Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Step 5: The Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Step 6: Build It! . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Step 7: Cutting the Breadboard Strips . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Step 8: The Board Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Step 9: The Barrel Jack . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Step 10: Build It! . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Step 11: Marking the parts placement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Step 12: Soldering the Resistors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Step 13: Soldering the Capacitors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Step 14: Soldering the Diodes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Step 15: Soldering the Power Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Step 16: Soldering the Barrel Jack . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Step 17: Soldering the DIP switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Step 18: Soldering the Regulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Step 19: Breadboard Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Step 20: Connecting everything together . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Step 21: Test It . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Related Instructables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Comments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

http://www.instructables.com/id/The-Radioshack%2c-Adjustable%2c-Breadboard-Power-Suppl/

Intro: The Radioshack, Adjustable, Breadboard Power Supply.This Instructable will show you how to build an adjsutable breadboard power supply entirely from Radioshack parts. It can provide multiple voltages directly to the powerrails on a prototyping breadboard. This could be useful for people on a low budget, who don't like to order parts online, or who need a good weekend project.

Image Notes1. Breadboard2. Power Supply

Step 1: The LM317The LM317, according to Wikipedia, isan integrated three-terminal adjustable linear voltage regulator. It supports input voltage of 3V to 40V and output voltage between 1.25V and 37V. It has a current ratingof at least 1.5A although lower current models are available. Its output voltage is controlled by a resistor or a potentiometer. The LM317 also has a built-in current limiteras a safety feature. LM317 is manufactured by many companies, including National Semiconductor and Fairchild Semiconductor. The LM317 will automatically reduceoutput current if it gets too hot under load. The use of a heatsink is recommended to extend the part's power-handling capability. LM317 is a positive voltage regulator. Itsnegative complement is the LM337

This will provide the Power in our Power Supply. It can also be found at a well-stocked Radioshack.

National Semiconductor's page

Step 2: Calculating the ValuesThe following formula will allow you to calculate the resistor values to set the LM317 to any voltage that you need:

R2=R1((V/1.25)-1)A standard R1 Value is 240 Ohms, so the final formula is:

R2=240((V/1.25)-1)I chose the following power values for my power supply:1.533.34.856

http://www.instructables.com/id/The-Radioshack%2c-Adjustable%2c-Breadboard-Power-Suppl/

912

So my resistor values are the following(some have two for greater precision):47330390680330 390820 10015001800 270

All of these resistor values can be found in the Radioshack 500 Piece Carbon Film Resistor Assortment.

Step 3: The PartsBarrel Jack--------------------------------SalvagedSwitch--------------------------------------275-409Rectifying Diodes-----------------------276-1653100uf cap----------------------------------272-1044LM317T Voltage Reg.------------------276-177810uf cap-----------------------------------272-1025.1uf cap------------------------------------272-135Header Pins-----------------------------SalvagedPrototyping Board----------------------276-0149500 Piece Resistor Assortment---271-312AHeat Sink--------------------------------276-13638 Position DIP Switch----------------275-1301BScrap PCB------------------------------Salvaged

http://www.instructables.com/id/The-Radioshack%2c-Adjustable%2c-Breadboard-Power-Suppl/

Step 4: The ToolsThese tools are common hobbiest items, most people should have:

Soldering IronSolderSolder WickWire (RS # 278-1221)MultimeterVarious PliersBig ScissorsDuct Tape

Step 5: The SchematicThis is your basic LM317 Schematic, with the DIP switch and the resistors added(Look at Notes!!):

Image Notes1. Should be 820!!!

Step 6: Build It!The Following steps will detail the construction of this power supply.

Step 7: Cutting the Breadboard StripsTake your scrap PCB, and mark outside a 7x8 rectangle. Use your large scissors to cut inside this rectangle. You should now have a 6x5 box. Cut this down the middle ofthe short side, finishing with two 6x2 strips. These will connect the power supply to the breadboard. Set these aside.

http://www.instructables.com/id/The-Radioshack%2c-Adjustable%2c-Breadboard-Power-Suppl/

Image Notes1. The Box

Image Notes1. The Final Use

Step 8: The Board LayoutIf you have followed my parts list, you should be able to copy this layout for your board.

Image Notes1. LM3172. 2x120 ohm resistors3. 100uf capacitor4. Switch5. Diodes6. 10uf Cap7. .1uf cap (104)8. DIP switch9. Resistors10. Resistors11. Area for Barrel Jack

Step 9: The Barrel JackThe Following pictures detail the steps of marking and drilling for the barrel jack. I used a 7/64 drill bit for the mounting holes.

http://www.instructables.com/id/The-Radioshack%2c-Adjustable%2c-Breadboard-Power-Suppl/

http://www.instructables.com/id/The-Radioshack%2c-Adjustable%2c-Breadboard-Power-Suppl/

Step 10: Build It!The following Instructions will detail the construction of this power supply.

Step 11: Marking the parts placementAfter you have the board layout completed, mark every part hole with a permanent marker so you can easily stuff the board.

Step 12: Soldering the ResistorsRemove all of the components except for the resistors. Place a piece of Duct tape over all of the resistors, holding them to the board. Turn it over, and solder each of theleads to the board. Finally, cut all of the component's leads off and remove the tape.

http://www.instructables.com/id/The-Radioshack%2c-Adjustable%2c-Breadboard-Power-Suppl/

Step 13: Soldering the CapacitorsPlace the capacitors in their positions, noting polarity, and put the tape over them. Flip it over, solder the components, clip the leads, and remove the tape.

http://www.instructables.com/id/The-Radioshack%2c-Adjustable%2c-Breadboard-Power-Suppl/

Step 14: Soldering the DiodesMostly the same as the last step, and remember to note polarity. LOOK AT THE PICTURE NOTES. Put them in their places, put tape over them, solder, clip, and removethe tape.

Image Notes1. WRONG DIRECTION2. WRONG DIRECTION

Step 15: Soldering the Power SwitchPut the switch in place, it shouldn't need to be taped. Flip it over, solder, cut the leads, and flip the board back over.

Step 16: Soldering the Barrel JackThis is probably the hardest part to solder, because the jack required me to drill out the pad, You have to solder to a nearby pad. You shouldn't need tape for this, and allthe soldering steps are the same.

http://www.instructables.com/id/The-Radioshack%2c-Adjustable%2c-Breadboard-Power-Suppl/

Step 17: Soldering the DIP switchAgain, more soldering. Tape the DIP switch in place, solder, remove tape.

Step 18: Soldering the RegulatorFinal Part!! Put the regulator in, tape it, solder it, cut the leads, And your done!

http://www.instructables.com/id/The-Radioshack%2c-Adjustable%2c-Breadboard-Power-Suppl/

Step 19: Breadboard ConnectionsTo connect the power supply to the breadboard, use 8 header pins and your 2x6 strips. Solder 2 sets of 2 header pins to the board where it will plug into the breadboard.Solder the strips to these, then solder the other header pins onto these strips, upside down. The pictures help explain the concept better. Also, I used resistor leads toconnect the two header pins.

Step 20: Connecting everything togetherThe following schematic shows which connections are to be intentionally bridged and which are to be connected with jumpers. The other pictures show my connections.

http://www.instructables.com/id/The-Radioshack%2c-Adjustable%2c-Breadboard-Power-Suppl/

Step 21: Test ItYour Done!!! Now that you have the power supply assembled, test every voltage to see if it is close enough to your desired voltage.

http://www.instructables.com/id/The-Radioshack%2c-Adjustable%2c-Breadboard-Power-Suppl/

Image Notes1. Supposed to be 62. Needs to be 820

Related Instructables

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PortablePoweredBreadboard andLED Tester bySoldier6575

USB powerhack, addingusb ports to aDX052 mixer byjarv34

http://www.instructables.com/id/The-Radioshack%2c-Adjustable%2c-Breadboard-Power-Suppl/

Comments50 comments Add Comment view all 61 comments

oldskooldawgz says: Feb 16, 2011. 3:58 PM REPLYy are there two 240 ohm resistors slot 22 n 23

ernie666 says: Feb 3, 2011. 9:42 PM REPLYwhy do u need capacitors?

beehard44 says: Jan 3, 2011. 1:00 AM REPLYlooks like the voltages are a little bit off. Why not use presets and calibrate so that you get the right voltages

jomac_uk says: Jan 2, 2011. 6:32 AM REPLYI like the switch idea, once set up, its a simple matter of selecting the voltage, without having the hassle of connecting up your volt meter, all in all its a goodinstructable!

hokie88 says: Sep 1, 2010. 4:43 PM REPLYWorks great thanks man, I used a dc input source so i got rid of all the diodes and didnt bother with the switch, I wish they made a much larger 8 rockerswitch

David_C says: May 4, 2009. 7:06 PM REPLYThere are 3 of us guys who tinker around doing electronics projects and we watch the youtube video by Kip Kay about getting Free Electricityfrom your phone line which is between 40~75 Volts ac and Kip showed useing a Bridge Rectifier as the input then the voltage goes to the Lm317voltage regulator.

http://www.youtube.com/watch?v=WoaLGvJkoP8

So why couldn't you use this input voltage to power your projects once you know that value that the phone line produces, as in this example by useing themethod he memtioned and adapting it to be a varabile power source by useing a 5k Trimmer pot and adding a volt meter to the circuit so you could fine tuneit to a voltage of 3v, 5v, 6v, 7.5v, 9v, 12v ect.

heres the link the the Jpeg image i came up with

http://i247.photobucket.com/albums/gg149/davidmann007/LM317withBridgeRectifierCircuit-1.jpgE-mail Address:Treasurehunterenterprizes@yahoo.com

Please Comment on this circuit if you think it would workby E-mailing me.

SincerelyDave

dagenius says: Nov 10, 2009. 3:45 PM REPLYI saw that earlier, on the make podcast, and I tried measuring the power from the phone line, but we ended up having to replace all of my phone modulesdue to them frieing from the energy draw that my multimeter created.

wkuace says: Aug 25, 2010. 1:15 PM REPLYAlso that is Illegal, and if the phone company notices what your doing they will shut off your phone and maybe sue you. If your want a cheap supplyto power this circuit buy an old ATX supply from ebay they are about $10 and work great. There are instructables that show how to convert them towork outside of a computer Or you could go to consignment stores and look around for an old wall-wart power supply that will meet your needs, Youcan get a whole printer at Goodwill for $5 and their are lots of extra goodies inside

Minifig666 says: Dec 5, 2009. 12:18 PM REPLY Would a 12v 2000mA power supply be capable of powering this unit?

kikiclint says: Aug 25, 2010. 9:15 AM REPLYIt gives a maximum voltage about 2 volts below what you put in, so yes it would. You would then have a 10 volt power supply.

http://www.instructables.com/id/The-Radioshack%2c-Adjustable%2c-Breadboard-Power-Suppl/

geeklord says: Jan 18, 2009. 5:14 PM REPLYi went to radioshack today, and they were all out of adjustable v-regs!!! I was a little upset....

beehard44 says: Apr 18, 2010. 11:52 PM REPLYgrab a free sample from ti

Artificial Intelligence says: May 30, 2008. 11:12 AM REPLYI've made this and it works great, nice job. There is one thing, I think is weird though, the LM317 heats up very fast. Even when it is powering a standard lowpower LED (10mA) it gets hot enough to melt plastic bags.

Derin says: Aug 20, 2008. 4:27 AM REPLYseems like a short

Artificial Intelligence says: Aug 20, 2008. 6:05 AM REPLYIt can't be, cause it works fine and I've checked the circuit board.

kersny says: Aug 20, 2008. 6:29 AM REPLYMake sure that your input voltage is not insanely higher than your output voltage(12v in for 3.3v out). Also, a heatsink helps if you don't alreadyhave one.

Artificial Intelligence says: Aug 20, 2008. 7:32 AM REPLYThat could be the problem. I supply it with 24 volts.

dagenius says: Nov 10, 2009. 3:49 PM REPLYyes, that would be it. voltage regulators regulate by turning the excess power into heat, and 24 volts to 3 volts would mean it would bedissipating 21 volts into heat. bad.

beehard44 says: Apr 18, 2010. 11:48 PM REPLYuse a heatsinki used the TO-92 package from Texas instruments. best of all, it was FREE!

Minifig666 says: Nov 28, 2009. 9:06 AM REPLY Can I ask what the diodes are for and why do you need two?

Minifig666 says: Nov 28, 2009. 9:31 AM REPLY Sorry I meant 4. Are they for AC/DC Conversion

beehard44 says: Apr 18, 2010. 11:45 PM REPLYi think he was using ac, so he needed to convert it

thestyrofoampeanut says: Mar 8, 2010. 11:10 AM REPLY the tape is a great ideai always used to put in components and bend the wires down so they would stay still

Xellers says: Nov 11, 2009. 3:17 PM REPLYAn excellent project - but I would personally prefer to use a potentiometer to regulate the voltage coupled with an analog voltmeter.

reaman4ever says: Apr 26, 2009. 3:26 PM REPLYhow do you make connections from one point to another on a board like this (where none of the points are connected)? Do you drag the solder somehow? isthere some kind of trick? I bought a whole bunch, but dont know how to use them. thanks

dagenius says: Nov 10, 2009. 3:46 PM REPLYyeah, you creat solder bridges, use jumpers, and wires on the bottom as well.

http://www.instructables.com/id/The-Radioshack%2c-Adjustable%2c-Breadboard-Power-Suppl/

MrNintendo says: Dec 4, 2008. 1:22 PM REPLYSweet instructable man. I've needed one of these for a good while, just now decided to see if anyone made these. One question though, on step 14, in themain pic, you said that 2 of the diodes were facing the wrong direction, but does it really make any difference? It might be a stupid question, but I'm still inhigh school, so I dont know much of this stuff, mind helpin me out?

Swishercutter says: Nov 9, 2009. 10:59 AM REPLYhyperphysics.phy-astr.gsu.edu/Hbase/electronic/rectbr.html

That might help explain the current flow in a bridge rectifier for you. Basically, it converts the AC signal to a pulsating DC signal (the capacitor on thebridge output smooths the pulses).

rcguymike says: Dec 22, 2008. 8:43 PM REPLYIt does matter because diodes allow current to only flow in one direction. It comes out the end with the stripe and in the other. If you hook it up backwardsit won't allow the current to flow.

ElectronMad says: Aug 12, 2009. 8:16 PM REPLYYea umm Nice... May i give a tip? Instead of using 8 pins just get 4 But how? simple Get a needle nose plier and you no the black part make it go to the verytop! Put it through And solder it then take of the black thing and put it on the front if wished keep on the top..

F-zero says: Jun 23, 2009. 4:19 PM REPLYGreat job on this! I made one for myself and it works great! I altered it a bit though.I made my own PCB board for it. Also, I added a fuse and a diode to be onthe safe side and I replaced the 4 rectifying diodes with a bridge rectifier. I also added the little wire clip thing instead of placing it directly into the breadboard.I learned alot while making this. Thank you very much! One last note, when the switches on the DIP-8 aren't turned on, the output power 35 volts. I don'tknow if its supposed to do that or its my board. But, other than that, it works like a charm. Thanks!

agis68 says: Feb 2, 2009. 3:21 AM REPLYNice job and well done. U mean the Radishack Console that one costs 70$? I was ready to order it but thanx to u i got it

FreeBaseBuzz says: May 24, 2009. 8:35 PM REPLY$70?$5 here: http://www.solarbotics.com/products/34020/

huitlacoche says: Apr 24, 2009. 10:55 PM REPLYWhat is the purpose of using 4 rectifying diodes instead of one and what is the advantage of having them in parallel? I'm not sure I really understand howthey are wired by looking at this schematic.

huitlacoche says: Apr 24, 2009. 11:10 PM REPLYOkay, thats a full-wave rectifier. I should've done the research *before* asking the question. Oh well.I figured this was just accepting a DC voltage source. But the rectifier will allow for AC now?

bombmaker2 says: Mar 3, 2009. 4:44 PM REPLYwat is the imput?

the judge says: Feb 8, 2009. 2:12 PM REPLYI accidentally reversed the power supply pins and blew up a capacitor :( what are the upper and lower limits on the capacitor voltages (I'm assuming 24v)and capacitance for this to work? I can't find a ceramic disk capacitor that has enough description on it for me to find spec on them ( I get most of mycomponents from old tech like stereos). the most description I could find on any of them was a 3 digit number or a voltage rating, but no capacitance rating,but I did find a film capacitor that has .1 uf, could I use that?

sarahsyakirah says: Jan 27, 2009. 10:55 AM REPLYwhat would be the resistance of the device that connected to the output terminal of voltage divider?? please answer me..

http://www.instructables.com/id/The-Radioshack%2c-Adjustable%2c-Breadboard-Power-Suppl/

rinthesun says: Jan 17, 2009. 4:04 PM REPLYProblem: If the power supply is in circuit and all switches are turned off almost the full wart voltage is connected to the breadboard. It would be safer to havethe resistors in series with a shunt. Of cause the resistor error would be more of a problem.

Barney Watches You says: Aug 30, 2008. 6:54 PM REPLYthis is an awesome idea! I'm going to make one.

Unit042 says: Jul 17, 2008. 9:01 AM REPLYClever stuff! Using a series of switches to vary the voltage divider. Usind a dipswitch is fine, but what's wrong with a 10k pot? My power supply is amystery transformer outputted to a heavy duty overkill full wave bridge rectifier which goes to a LM2937.I get 12-15v from transformer, and regulated 5v from, well, the regulator. Oh,and don't forget GND!PS: It may be common knowledge among 'iblers (people who make 'ibles), but is there any way I can see a higherresolution and larger size version of the images i.e. schematics?

lifelong-newbie says: Aug 15, 2008. 11:40 AM REPLYYou can see some different size scalinngs of the pictures by clicking the i in the top left corner of the pic and selecting the image size you want.

Unit042 says: Aug 19, 2008. 7:10 PM REPLYCool. Thanks!

Unit042 says: Jul 17, 2008. 9:12 AM REPLYNice soldering! Did you do it nice and pretty just for the 'ible? Mine isn't pretty but it gets the job done.

wbornor says: May 22, 2008. 10:40 AM REPLYwhat tool do you use to draw your schematics?

kersny says: May 23, 2008. 4:16 AM REPLYI use cadsoft eagle from cadsoft.de. Its hard to get started, but once you get used to it, it works really great. Sparkfun.com has some great tutorials onthe subject.

dean-101 says: Mar 13, 2008. 3:54 PM REPLYcan some one please help me. i need a power supply (a uk adopter) for running all the projects i make but i have a lot of adopters laying around and i dontno if they are safe to use. would a 5.2v 100ma be safe to use if i cut the end off and use croc clips? or a 3-20 v 3000ma bench top power suply? if none ofthese will be safe can anyone tell me one that will be safe plus could they do damage or shock you if i touched the ends by mistake?? please help thanks

Xophlix says: Apr 2, 2008. 7:54 AM REPLYI took two 9V batteries and connected them in series for a super-bright LED flashlight. Their drawing about 36 mA 100 mA wont shock you, im not surewether the other one will, better to be safe than sorry what is that charger for? i cant find one that outputs less than 1000mA

dean-101 says: Apr 2, 2008. 9:01 AM REPLYit was off an old drill battery charger. weird thing is that the 5v charger was used to charge a 9.6v drill, but it worked fine. the 3000ma one is adesktop power supply i can get for 20 and it has different voltages that you can change

dfowler7437 says: Feb 21, 2008. 10:37 AM REPLYI did a simular power supply design with the bridge rectifier. I did not put a dip switch to select the ouput voltage but I did bring out the adjust pin so that itcould be done on the breadboard.

http://www.uchobby.com/index.php/2008/02/19/bread-board-power-supply/

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