Dual Polarity Power Supply


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This dual polarity power supply is easy to build, requires few parts, and is adjustable from 0-15 volts. It is great for powering op amp circuits, as well as other circuits that require a dual supply voltage.

Schematic

This is the schematic of the Dual Polarity Power Supply

Parts

Part
Total Qty.
Description
Substitutions
C1, C222200uF 35V Electrolytic Capacitor
C3, C4, C5, C741uF 35V Electrolytic Capacitor
C6, C82100uF 35V Electrolytic Capacitor
R1, R425K Pot
R2, R32240 Ohm 1/4 W Resistor
BR112A 30V Bridge Rectifier
U11LM317 Adjustable Positive Regulator
U21LM337 Adjustable Negative Regulator
T1130V Center Tapped 2 Amp Transformer
S11SPST 2 Amp Switch
MISC1Heatsinks For U1 And U2, Line Cord, Case, Knobs For Pots, Wire

Notes

  1. Since this project operates from 120 (or 220, or 240, etc.) volts AC, it MUST be built inside a case.
  2. U1 and U2 get quite hot and will require heatsinks. A fan is usually not needed.
  3. You can, of course, add a volt and amp meter.
  4. U1 and U2 can only go down to a minimum of +-1.2V. If you need to go lower, you can add two 1N4003 diodes in series with the output of the regulator. The diodes drop about 0.6V each, which will allow the supply to go to 0. Note that this will also decrease your maximum output voltage by 1.2V. (Thanks to Steve Horvath for the suggestion).

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Comments

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anonymous
Dual Polarity Power Supply
Monday, May 20, 2013 7:30:52 AM
I simulated the above circuit in Multisim & found the load currents to be very low(about 0.5mA). Can u suggest a way to increase the load current to about 2A.
anonymous
Dual Polarity Power Supply
Friday, January 13, 2012 10:39:50 AM
Hi,i really need help on how to design a dual channel DC power supply that fulfills the following specifications : 1) Operation - User selection between independent adjustment for positive and negative output voltage, and series tracking mode (slave channel tracks the master channel) 2) Output voltage amplitude : 0-20V� 5% 3) Current limit : 0 - 1.5A� 10% 4) Powered Directly from main supply 5) Indications of power on, constant voltage and constant current mode I really hope you guys will be able to help me and provide me with a schematic to achieve the above specifications..thanks in advance =)
anonymous
Dual Polarity Power Supply
Wednesday, December 07, 2011 2:10:55 PM
Hi perhaps some one could design a pcb for the circuit and layout, it would make the authors design far more superior
anonymous
Dual Polarity Power Supply
Friday, November 05, 2010 7:37:50 PM
To the guy below. R1 and R4 are potentiometers. It's okay to leave one side unconnected.

(Editor's notes: Sure, if you want noise...)

anonymous
Dual Polarity Power Supply
Monday, October 18, 2010 10:04:13 AM
The R1&R4 where is it going to connect.. is it short circuit or what please answer
M.Khalid Ansari
Dual Polarity Power Supply
Wednesday, October 13, 2010 10:23:26 AM
I made this dual power supply two times but it doesn't work. Only transformer is heating up. After that I made single power supply by eliminating LM337 and other capacitors then it works properly. Please guide me, why dual power supply is not working?
Opcode
Dual Polarity Power Supply
Monday, August 16, 2010 2:33:53 AM
Better way to go below 1.2V (well, 1.25 to be exact) is to tie the R1 pot to -1.25V (instead of ground as shown) and R4 pot to positive 1.25V.
anonymous
Dual Polarity Power Supply
Friday, July 30, 2010 2:32:26 AM
can you please send me a circuit diagram of a dual power supply regulator to supply currents between 0 and 1.5A to a variable load resistor at a voltage of 2 to +12V
vp_archer
Dual Polarity Power Supply
Friday, June 25, 2010 12:02:14 AM
the junction between capacitors: are they connected to GROUND? from the diagram i see a "dot" there, but will that cause any problem? thank you.
anonymous
Dual Polarity Power Supply
Monday, December 21, 2009 11:11:48 AM
I want to know about the Input, Output and Ground of U1 and U2. I mean what are 1, 2, and 3. Can you reply it to my mail? Thank you.
daphne jane peralta
Dual Polarity Power Supply
Friday, June 26, 2009 4:32:42 AM
nice one! i'll be making a power supply soon..
Rudianto C
Dual Polarity Power Supply
Monday, June 15, 2009 6:32:01 PM
Hi, I am going to built a center tap power supply + - 110VDC. Is it possible to use directly bridge diode 50A 1000V and 2 serial Capacitor 10000 uF 200V without trafo apply to electrical power 220 VAC ?
Tipu
Dual Polarity Power Supply
Sunday, June 07, 2009 12:14:39 PM
Would it possible to devise a Dual polarity Power Supply by using only 7812 Voltage Regulator and transistors. i.e not using LM317 and LM337.
anonymous
Dual Polarity Power Supply
Wednesday, March 11, 2009 6:04:50 AM
PLACE A 10uF electrolityc between pot wipers and ground. this will iprove hum rejection and Kf...I would put a 100R trimpot in series with one of the pots, because you can never get a double pot that has equal resistances on both sliders.
Mark
Dual Polarity Power Supply
Thursday, February 19, 2009 7:49:10 AM
How is it possible to vary voltage from 0 to 30V instead of 0 to 15V?
Jeff
Dual Polarity Power Supply
Tuesday, February 10, 2009 5:04:48 AM
This is the same exact circuit that the data sheet for the LM317 shows for a 1.2V - 25V power supply. This one is just using a center tapped transformer to feed the bridge. The circuit from the data sheet is copied except using, on the bottom it uses an LM337 as the regulator. The center tap is the DC circuit ground. Real original.

(Editor's notes: How odd that it's on the datasheet, as I designed this circuit some 15 years ago for a project and have never even looked at the datasheet for these ICs.)

vinod deshmukh
Dual Polarity Power Supply
Wednesday, January 14, 2009 10:23:09 PM
I need dual polarity power supply cvircuit diagram without using centert tap transformer(or if possible,without using transformer i.e. 'transformerless dual power supply'
anonymous
Dual Polarity Power Supply
Friday, October 03, 2008 4:35:18 PM
Your C1 and C3, C2 and C4, C5 and C6, and C7 and C8 are in parallel which looks like overkill. For example, you simply have a 2201 micro Farad cap made out of C1 and C3. Was this for some purpose?

(Editor's notes: Filtering.)

anonymous
Dual Polarity Power Supply
Tuesday, September 09, 2008 12:45:11 PM
I only need d schematic diagram of the +15v and -15v dual power supply and the components
Simon
Dual Polarity Power Supply
Sunday, July 06, 2008 10:56:25 PM
Hi, I like the dual supply circuit, and would like to know if Transformer T1 has no centre tap, with the rest of the circuit remain the same, is the GND still applicable? Singapore.
Allen Walker
Dual output DC Power supply(output=+15v and -15v) with less than 15 components
Monday, June 16, 2008 1:21:38 AM
Hi, Can i have the schematic diagram of a dual output DC power supply of output +15 volts and -15 volts and the schematic diagram with not more than 15 components in it. Help me to identify the sub-sections[explanation of each and every component] that make up the power supply and an explanation on the operation of the power supply. Thank you. Please reply ASAP.
JL
Dual Polarity Power Supply
Monday, June 09, 2008 2:49:37 AM
Hihi.. Ur notes say that U1 and U2 can only go down to a min of+/-1.2V if add two 1N4003 diodes in series. Than how to make a power supply with a voltage output range from +15V and -15V?
maria
Dual Polarity Power Supply
Wednesday, June 04, 2008 6:30:15 AM
i am not getting any idea about how to connect the U1 and U2 ics, because the pins are labelled as Vin, Vout and adj in the data sheet, but here the pins are labelled as 1,2,3. can anyone guide me???

(Editor's notes: U1: 3 = In, 1 = Adjust, 2 = Out U2: 2 = In, 1 = Adjust, 3 = Out)

hammad chohan
Dual Polarity Power Supply
Tuesday, April 29, 2008 2:16:21 AM
its good but put some alternative component then it can be a very good project 4 the begar
Fuzail (PAF-KIET)
Dual Polarity Power Supply with max 5 amps
Thursday, April 24, 2008 3:28:51 AM
any one around who can send me circuit diagram of dual polarity variable power supply having 5 amp max current
Kirk
Dual Polarity Power Supply
Sunday, April 06, 2008 6:48:02 AM
Genius wanted. Anyone got a design for a +/- 48v regulated power supply. I have an Infinity Sub Woofer that suffers from hum. I have determined that the power rails are not smooth and even with extra capacitive smoothing it is not good enough. I wish to ensure that the power supply is as smoth as it can be. Many thanks to anyone who can help. Kirk.
anonymous
Dual Polarity Power Supply
Friday, March 07, 2008 10:48:10 AM
A fuse would be rather a good idea, as would an earthed chassis and dual pole dual throw switch to
Aran Sander
Dual Polarity Power Supply
Thursday, February 21, 2008 11:04:00 PM
how do you compute for the value of each parts for this design? can you give me the computation and the process how do you design and the operation of the design. you can email me @ aran_sander_14@yahoo.com , hoping for your reply thanks a lot
EDWIN
Dual Polarity Power Supply
Tuesday, February 19, 2008 8:05:40 AM
Hi, just wanted to know if you did experience any problems with the outputs, meaning did you ever come across different output voltages between the +ve amd -ve outputs? i need a reply ASAP thank you
josh
variable power supply with 3 -5A and cheaper
Tuesday, February 19, 2008 3:57:10 AM
do you have a design of power supply virable and can accept up to 5A and cheaper and in minimum size
Matt
Dual Polarity Power Supply
Tuesday, January 29, 2008 6:33:51 PM
I have to build a power supply for a class project and i have never built one before. what do you think would be the best way to go
Aska
Dual Polarity Power Supply
Thursday, January 24, 2008 4:14:48 AM
does work this circuit work in a 220 outlet and can produce a negative and positive 15 volts output
edwin
Dual Polarity Power Supply
Tuesday, January 22, 2008 5:31:33 PM
i have chosen this circuit as my project in my college course but i just want to know if you have actually tested this circuit and got the results you expected?
henry
Dual Output DCPower Supply 15+volt
Saturday, January 05, 2008 11:16:06 PM
do u have a time pls explain me the operation of power supply thanks henry
Muhammad Asad
Variable voltage
Saturday, January 05, 2008 3:04:59 PM
How is it possible to vary voltage from 0 to 5V instead of 0 to 15V?
mark
Dual Polarity Power Supply
Monday, December 31, 2007 12:00:53 PM
Hi, may i ask for your idea on how to make a power supply with a voltage input range from -5 to +15V?
neha
Dual output DC Power supply(output=+15v and -15v) with less than 15 components
Wednesday, December 26, 2007 3:45:42 AM
Hi, Can i have the schematic diagram of a dual output DC power supply of output +15 volts and -15 volts and the schematic diagram with not more than 15 components in it. Help me to identify the sub-sections[explanation of each and every component] that make up the power supply and an explanation on the operation of the power supply. Thank you. Please reply ASAP.
ANSAR ABBAS
Dual Polarity Power Supply
Friday, December 14, 2007 4:53:46 AM
PLEASE GIVE THE TOTAL INFORMAYION ABOUT THE DUAL VARIABLE POWER SUPPLY
Sreenivas
Dual Polarity Power Supply
Wednesday, November 28, 2007 7:08:00 AM
i want circuit design of dual polarity power supply using with 7805 and 7905 regulators.
danilo reyes
Dual Polarity Power Supply
Saturday, November 24, 2007 8:50:15 AM
ill give this to my sutdents! ayt?
Luis Martinez
Dual Polarity Power Supply
Monday, November 19, 2007 3:13:30 PM
I am trying to design a dual power supply with an ouput voltage of 30V -50V and 2-6amps. How could I do this any ideas
Sumon
Dual Polarity Power Supply
Friday, November 16, 2007 1:05:36 PM
I need a dual power supply of rating of 5A,15V
anonymous
Dual Polarity Power Supply
Wednesday, November 07, 2007 12:01:06 AM
To huckeney wallace, Go to a Maplin store, they carry both the LM317 and LM337. There are several Maplin stores in London, UK. Or just about any other electronics supplier in the UK, although many are Internet/mail order with no store front.
anonymous
Dual Polarity Power Supply
Thursday, October 18, 2007 11:14:12 PM
anyone got 35V dual polarity PS, thanks a lot log betlog
anonymous
variable power supply
Wednesday, October 17, 2007 9:47:53 AM
i need 5-25 voltage output variable power supply with potentiometer. including schematic diagram and block diagram.
huckeney
Dual Polarity Power Supply
Thursday, October 11, 2007 5:28:14 AM
dear sir madam My name is huckeney wallace and i'm a student at lambeth college in london united kingdom. I have an interest in doing this circuit and the problem i have with this circuit is is the regulators u1 and u2 value. I would like to know if the measurement you got form doing this circuit practically was symmetrical please answer back with any tips you can offer me in this area. p.s i will be waiting a reply...
huckeney
Dual Polarity Power Supply
Tuesday, October 09, 2007 7:24:32 AM
Good day sir i'm a student studying electronics engineering in college in london, united kingdom and i'm interested nin doing your circuit ... my problem is the regulators i would like to know where did you get them from?
anonymous
Dual Polarity Power Supply
Wednesday, September 19, 2007 6:07:23 AM
Good Day Can you please provide me with a dual voltage power supply schematic for +15VDC to -15VDC voltages using center tap transformer
Dominador Q. espiritu III
single Polarity Power Supply
Wednesday, September 12, 2007 4:52:01 AM
i need a schematic diagram of a regulated power supply 0V-30V, 3A
anonymous
variable power supply
Sunday, September 09, 2007 2:30:37 AM
i need 5-25 voltage output variable power supply with potentiometer. including schematic diagram and block diagram.
stanley
Dual Polarity Power Supply
Wednesday, August 22, 2007 10:49:53 AM
I need a dual power supply of rating of 5A,15V
ms.mehranian
Dual Polarity Power Supply
Wednesday, August 22, 2007 2:43:40 AM
hello sir v have given a task of mini projects so kindly grant me a fully described circuitry of variable dual power supply of 0-30v.
sanjay maji
high voltage Power Supply
Tuesday, August 21, 2007 6:13:31 AM
i need -1000 & -100 volt power supply ckt. diagram
venkatachalam
power supply
Tuesday, August 21, 2007 2:35:04 AM
hello sir, i want to design a ( 0 - 32 v) variable power supply with low current rating . so i request u to send me the necessary details thank u
anonymous
Dual Polarity Power Supply
Monday, August 20, 2007 2:17:58 PM
gud day.can you please send me an schematic of a dc to dc daul power supply with a input of 12VDC, output of +12VDC and +5VDC
Matt
Dual Polarity Power Supply
Saturday, August 18, 2007 11:39:07 AM
For the capacitors, do they have to be 35v exactly or can it be any value over 30v?
Donovan
Dual Polarity Power Supply
Sunday, August 12, 2007 5:18:43 AM
Dear sir, i am currently a student at the university of KwaZulu Natal and i've been tasked with designing a dual rail power supply of +/- 5V dc out. I have presviously built a regular dc power supply of output +5V with a source voltage of 220 VAC. I pretty much understand the first half of the power supply schematic at the top of this page but could you please explain to me as to how i could get a negative voltage out, preferably -5V. A schematic would be helpfull. Also, what is the difference in design between a "positive dc output" power supply and a "negative" one? Thank for your time.
anonymous
Schematic diagram of a Variable power supply Power Supply
Friday, August 10, 2007 5:13:56 AM
Can you please help me design or give a Schematic diagram of a Variable power supply Power Supply (0-15 volts/ 0-3 amperes) with the only of resistors,transistors,capacitor and transformer.I am a 3rd year engineering student. Please e-mail me at wizard16jeff@yahoo.com
anonymous
Dual Polarity Power Supply
Thursday, August 09, 2007 6:38:17 AM
Hi, I need to design a dual power supply from a 12V back up source and deliver +/-12V to the rest of the circuitry. My concern is that I have a relay that switches this back up source ON when the main supply fails and this relay only has three contact points (n/o; c/c and com). That is, if I want to take this dual back up through the relay, I'm going to need a fourth contact point for the ground. Can u help? I hope this makes sense
anonymous
Dual Polarity Power Supply
Thursday, August 02, 2007 9:15:34 PM
the role of r1 and r4 is to adjust the output voltage that u need
Stefano74
Dual Polarity Power Supply
Tuesday, July 17, 2007 12:20:41 PM
Hello, which is the role of R1 and R4 ?
payal
Dual Polarity Power Supply
Tuesday, July 17, 2007 4:29:36 AM
this circuit has been presented in a very easy and lucid form that is very easily understood
ANdrew
Dual Polarity Power Supply
Wednesday, July 04, 2007 10:48:32 AM
Can i have the schematic diagram of a dual output DC power supply of output +15 volts and -15 volts and the schematic diagram should have not more than 15 components in it. Thank you. Please reply ASAP.
murunga
Dual Polarity Power Supply
Wednesday, July 04, 2007 5:28:20 AM
the circuit is so wonnderful, am a student at the university of nairobi taking electrical and electronics engineering can you send me more simple project oriented circuits as one above?
anonymous
Dual Polarity Power Supply
Monday, July 02, 2007 10:44:15 AM
how is varible voltage obtained?
japs
Dual Polarity Power Supply
Thursday, June 28, 2007 7:00:15 AM
hey! pls help me to have some dual polarity power supply with an output voltage of 0-30V and output current of 6A. Pls include the connection of the voltmeter in the ckt so that there's no need to measure. thanks a lot!
joey
Dual Polarity Power Supply
Monday, June 25, 2007 1:33:03 PM
Can i have the schematic diagram of a dual output DC power supply of output +15 volts and -15 volts and the schematic diagram should have not more than 15 components in it. Thank you. Please reply ASAP.
syafiq
Dual Polarity Power Supply
Monday, June 25, 2007 5:23:57 AM
can u show me more about dual output dc power supply.....
anonymous
Dual Polarity Power Supply
Thursday, June 21, 2007 10:07:35 PM
does anyone have a circuit for +35-0--35V dual power supply
pwerle
Dual Polarity Power Supply
Wednesday, June 20, 2007 2:44:49 PM
Why are you suggesting the 1uF caps in parallel with the 2000uF caps? Since capacitors add in parallel, aren't they kind of superfluous, especially if they're just their for filtering?
Moncef Mabrouk
adjustable Power Supply (alternative 0V AC 230V AC, 0V CC 24 V CC
Thursday, June 07, 2007 11:20:27 AM
Could you please send us the electric schematic of power supply : Adjustable alternative power supply( 0V 230V) Adjustable Continual power supply ( 0V 30V) I thank you for your help
dumudu
related treanformless power supply
Sunday, June 03, 2007 10:29:05 PM
dear sir i am willing to make power supply cirkits because i am electronic technician so if you have transformeless power supply cirkits below 35volts with 10amp or below please maol me have a nice day thank you
AMNA WAQAR
Dual Polarity Power Supply
Tuesday, May 29, 2007 1:05:26 PM
what is advantage o using IC instead of zener diode?
Juan
Dual Polarity Power Supply
Monday, May 21, 2007 2:21:38 PM
What will be the procedure to make the above power supply with a single Potentiometer for controlling both + and -? Very good circuit.
praneeth
Dual Polarity Power Supply
Sunday, May 20, 2007 11:19:12 PM
this is indeed a very nice circuit and has a good scope to learn the things clearly
fabian
Dual Polarity Power Supply
Wednesday, May 16, 2007 5:25:33 PM
thanks a lot. I will want a 24, -24 dual supply
Kidz (SA)
Variable Dual Polarity Power Supply
Tuesday, May 08, 2007 8:28:11 AM
Would like to myself build a portable -15 to +15V variable dual polarity power supply. Your assistance wil be highly valued.
simba
Dual Polarity Power Supply
Saturday, May 05, 2007 2:26:19 PM
it great cicuit
Muhammad Danish
Dual Polarity Power Supply
Wednesday, May 02, 2007 3:45:31 AM
100 % Working and tested no problem
mohamed abed
Dual Polarity Power Supply
Saturday, April 21, 2007 5:29:06 PM
i want a 12,-12 dual power supply circuit
SA
Dual Polarity Power Supply
Tuesday, April 17, 2007 12:38:29 PM
Guys, is it ok if I use voltage regulators(7805,7905) instead of Adjustable Positive Regulators?
ali
Dual Polarity Power Supply
Thursday, April 05, 2007 10:59:08 AM
thats a good circuit but i also wanna circuit of battery of +9 v and -9 v so if someone has it so plz send to my email address thank u all
scotty243
Dual Polarity Power Supply
Monday, March 26, 2007 11:59:06 AM
Um What Are you trying to Say? i could help, but i dont understand what you mean.
samurey
Dual Polarity Power Supply
Thursday, March 08, 2007 9:07:18 PM
Did I try this, my Condensator early running broke, but suggest C1,C2 doesn't using 2200uf but there must 4100uf.
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