Transformerless Power Supply


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I have received a few emails asking for a transformerless power supply. Here is such a supply. This supply uses no heavy step down transformer and has an extremely low parts count. The circuit can be built very small and can supply small currents for small projects. The major downfall of this supply is that it is not isolated from the AC line and can only supply small currents.

Schematic

Schematic for Transformerless Power Supply

Parts

Part
Total Qty.
Description
Substitutions
C110.39uF 250V Capacitor
C21220uF 25V Electrolytic Capacitor
D111N4741 11V Zener Diode (See Notes)
BR111 Amp 200V Bridge Rectifier
MISC1Line Cord, Board, Wire, Case

Notes

  1. The value of C1 can be increased to increase the amount of current the circuit can supply. With the values shown, the circuit can supply up to about 15mA. Remember to increase the size of C2 also.
  2. A different value can be used for D1 to increase or decrease the voltage as needed.

  3. Please note that this circuit is not isolated from 120VAC. Because of this, the circuit must be treated with caution and encosed at all times. Do not work on the circuit (or any other circuits attached to it) when it is plugged in.
  4. You may want to add a resisor in series with C1 to limit current if the circuit is plugged in and the mains is at its full voltage.
  5. If you are running the circuit from 220VAC, then use a capacitor rated at greater than 400V for C1.
  6. If you want isolation from the AC line, you can connect up a small isolation transformer at the inputs of the circuit. Small 600ohm:600ohm audio transformers work nicely.

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Comments

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anonymous
Transformerless Power Supply
Tuesday, November 29, 2011 10:07:55 AM
could this circuit be possible in a photo switch streetlights?
XN
Transformerless Power Supply
Sunday, November 13, 2011 9:09:36 PM
is it possible to connect an LM317 after the bridge rectifier for the transformerless power supply...like this one on your page?
anonymous
Transformerless Power Supply
Sunday, November 13, 2011 9:18:22 AM
1. Please indicate polarity of C1. All 400v capacitors i find are rated + and - on the pins. C2 polarity is clear. 2. I am trying to convert from 220v ac to 30v dc supply, can i use 30V rated Zener diode and 45v rated C2 ?????
frq
Transformerless Power Supply
Tuesday, January 04, 2011 10:23:59 PM
I am searching for a transformerless power supply with high current rating. Output-12V,and high current rating
anonymous
Transformerless Power Supply
Wednesday, September 15, 2010 4:10:28 AM
hi. is it safe if 10th std make this circuit and show its working for a science woking model fair.
anonymous
Transformerless Power Supply
Sunday, September 05, 2010 3:09:13 AM
i, I would like to know what would happen if (line voltage : 220 - 240 v 50 Hz) : 1 what modifications would be neccessary to protect the circuit conditions. Thank you!
anonymous
Transformerless Power Supply
Thursday, April 22, 2010 3:00:36 PM
hi, could you pls tell me how much voltage does this curcuit supply ? thanks
Sundeep
Transformerless Power Supply
Sunday, February 07, 2010 6:35:47 AM
Hi, I would like to know what would happen if (line voltage : 220 - 240 v 50 Hz) : 1 The voltage drops to 120v 50Hz. 2 The circuit is switched on at line voltage 300v 50 Hz. what modifications would be neccessary to protect the circuit in both conditions. Thank you!
Ehet
Transformerless Power Supply
Friday, December 11, 2009 9:31:29 AM
Build this power supply in a case
camil
Transformerless Power Supply
Wednesday, September 23, 2009 7:32:44 AM
dear techineer, pls i would like to have detailed explanation on why each component is used esp. C1 and C2 thanks
anonymous
Transformerless Power Supply
Saturday, September 19, 2009 4:19:42 PM
it seems that a resistor must be in series with c1 but in this circuit it is not .Please tell me is this resistor need or no if it is how determine its value?
John Kandankerry
Transformerless Power Supply
Tuesday, July 28, 2009 10:59:56 PM
Very neat and compact cct. However, I want to design a transformerless cct to supply 120mA DC at 42 V to a cluster of LEDs. Pl. advise how I should alter/ redo this cct. Thanks John
Amit Singh
Transformerless Power Supply
Thursday, July 16, 2009 5:18:57 AM
I want to know sumthing. how do i know C1 or C2 values? if i want to make other non transformer circuit? i have downloaded a software for circuit designing. from http://electronis-lab.com . it designs me circuit and give me uf value but it do not specify VOLT of C1 or C2. how do i know this? the link is to download ELECTRONIC CIRCUIT DESIGN and it only 168 kb. " http://www.electronics-lab.com/downloads/schematic/index.html "
anonymous
Transformerless Power Supply
Friday, June 19, 2009 3:34:01 PM
renhe: this circuit can supply up to about 15mA and halogen bulb demand 100/12*1000 = 8333mA.
anonymous
Transformerless Power Supply
Sunday, June 07, 2009 6:06:14 AM
Where standby generators are required to take over, in case of mains supply failure, transformerless supply is used to operate relays. These relays switch over the AC load from the AC mains to the generator and back as required. But the relay coils work on 12 or 24volts DC. These relays are fitted on to the AC Mains supply panel which is accessible to only trained personnel. So the risk is as much as handling the mains equipment only. In such a situation without increasing the risk, the cost benifit is very subsatntial for the equipment manufacturer!
neonlight
Transformerless Power Supply
Wednesday, May 20, 2009 6:37:12 PM
Techineer, First of all great site and thank you for the info. (1)There is one part i dont understand though, why must you place the resistor between C2 and the cathode? And not in series with the capicitor, i may be tired or missing the point but could you please explain the reason? (2)Oke i have got another question can i calculate the resistor simply with u/i=r where U for Europe would be 230 AC and for the US 120 AC and I the current is U/R=I --> (1.4... * volts_ac)/2fC1 ? thanx, neonlight
renhe
Transformerless Power Supply
Saturday, February 14, 2009 11:06:06 PM
i want to ask anybody if the supply from this power supply can use to halogen bulb 100w 12volts? if can used this supply on this bulb? thank you..
anonymous
Transformerless Power Supply
Wednesday, December 31, 2008 12:00:28 AM
i have already made this transformer less power supply, but i have lot of question about this. all of them have been asked by other friends here. i also want to answer of these question, tell what i have to do find the answer.
Techineer
Transformerless Power Supply
Monday, December 29, 2008 11:07:24 PM
C1 is being used as a current limit and voltage dropping device. The reactance of 0.39 uF capacitor at 60 Hz is 6800 ohms, but it uses no power and does not heat up like a resistor would. The output of this supply will vary widely as more current is drawn from the output, as more voltage will be dropped across C1. To calculate the output voltage, the load current must be known.
Techineer
Transformerless Power Supply
Monday, December 29, 2008 11:01:25 PM
NY - To use zener diodes for a 15 volt supply, you should place your resistor between C2 and your zener cathode, then take the load from across the zener. You may appear to have a square wave output if you connect the scope ground to the power supply negative output and use the probe on the positive output. This is because the scope ground is at AC Line Neutral potential, while the negative terminal output of your power supply is not. When you connect the scope ground to the negative terminal, you are shorting out a pair of the rectifier diodes. To properly observe the output requires that you use a dual trace scope set for differential mode (B-A), using ch2 at the neg output and ch1 at the positive output and the scope common connected to the AC Neutral wire. Set both channels for 5 V/div direct coupling.
NY
Transformerless Power Supply
Saturday, December 27, 2008 3:00:29 AM
I build the transformerless power supply, I added a resistor (100 ohms) in series with C1 (1.47 microF), the bridge rectifier (1N4007 x4), Zener diode D1 ( 3 Zener diodes in series to get 15V) and C2 470microF. I got a squarewave of 15V, could you please advise?
chibuzo Nnonyelu
Transformerless Power Supply
Thursday, December 11, 2008 10:43:07 PM
You have a wonderful site running. I give you that. My problem is that I live in Nigeria and most of the components in your design cannot be found in this part of the world. I will like you to use components that are easily fetched. Thanks
Wook
Transformerless Power Supply
Wednesday, September 24, 2008 11:31:31 PM
Transformerless power supplies are a VERY dangerous and bad idea. Transformers are far safer, and infinitely less expensive than the costs for a funeral.
QUENIEs
replacement
Sunday, September 21, 2008 1:52:58 AM
i just wanna know what should i used or what can i replace for c1 coz that value is not available in our place... please please
istian_69
Transformerless Power Supply
Thursday, August 28, 2008 10:53:10 AM
iam a begginer here can i ask what kind of capacitor in c1 should i use?
anonymous
Transformerless Power Supply
Saturday, July 26, 2008 1:44:05 PM
Can I use this trnsformless supply on 220 V AC?
bir
Transformerless Power Supply
Wednesday, July 23, 2008 4:25:30 PM
Can anyone help me out with 110 to 230VAC supply for transformerless with output of 6VDC 500ma circuit for battery charging. plz reply to my mail.
fredy frank
Transformerless Power Supply
Saturday, June 07, 2008 4:44:33 PM
what is the function of C1 what is the current and voltage drop after the bridge when the supply is 220v
Haas
Transformerless Power Supply
Tuesday, May 20, 2008 3:40:48 PM
Hi Aaroncake! Great Stuff!! I would like to know if using capacitors in parallel will increase the current o/p capacity. 2. how is the bleeder resistor value calculated, if used? Thanks alot Haas
krishna
Transformerless Power Supply
Friday, April 25, 2008 6:50:17 AM
can u give us design for transfomerless power supply 230V ac to 24V dc
Corey
115VAC to 24VDC ~6A Transformerless Power Supply?
Thursday, April 24, 2008 5:10:11 PM
looking for a schematic for a resticked space power supply... and as we all know, a transformer to handle this would be huge and too large for the space available in my project... any help would be great... thanks...
Moin-ud-din
Transformerless Power Supply
Thursday, April 10, 2008 4:57:17 AM
Sir, thanks i read your design tips. It was a nice document. I want to design a transformerless 200mA power supply kindly tell me how much value of capacitor i could used. regards, Moin-ud-din
tanH thiagarajan
230vac-24vdc-12vdc Transformerless Power Supply
Wednesday, April 09, 2008 10:55:33 PM
i need circuit diagram of a tranformerless power supply. input 230vac reduce to 24vdc and reduce it again to 12vdc and again to 5vdc. plz send it to my email.. i'm glad if someone help me..
tanH thiagarajan
240vac- 24vacTransformerless Power Supply
Saturday, April 05, 2008 11:40:18 AM
i would like to know more about this 240vac-24vac transformerless power supply.. if can i want it's circuit diagram.. i'm glad if someone help me..thank you..
poojaonymous
Transformerless Power Supply
Wednesday, March 26, 2008 6:22:22 AM
Can anyone help me out with 110 to 230VAC supply for transformerless with output of 6VDC 500ma circuit for battery charging. plz reply to my mail.
Mike
Transformerless Power Supply
Monday, February 25, 2008 11:05:28 AM
Please help me to design a 120vac to 12v dc 300mA tramsformerless power supply. Any schematic diagram.
chibuzo nnonyelu
Transformerless Power Supply
Saturday, February 23, 2008 9:01:46 AM
Please can I use this circuit on 220V AC power supply
HC
Transformerless Power Supply
Friday, February 15, 2008 2:23:05 AM
i need a transformerless power supply for 240vac input and 24vdc 1amp output. can somebody help me. thanks. best regards. HC
Nuno
Transformerless Power Supply
Monday, February 04, 2008 12:17:13 PM
Just to remember all that this kind of circuit works by capacitive reactance (C1) and is very limited in terms of current that it can supply. The maximum supplied current can be calculated by Ohm's law I = V/R, where I: represents current, V: voltage (mains in this case), and R: resistence (capacitive reactance in this case Xc). Where Xc=1/(2.Pi.f.C), Xc: capacitive reactance; Pi: 3.14; f: frequency; C: capacitance. As one can see, to increase current is necessary decrease the capacitive reactance (Ohm's Law), and for that we need to increase capacitance (capacitor size). Above 20-30mA this is no longer feasible because the capacitor becomes too big and expensive, so above these currents it is better to choose other method of conversion (Transformer or SMPS- switch mode power supply ).
Jpoy
Transformerless Power Supply
Wednesday, January 30, 2008 7:08:11 PM
Does the circuit supplying a 5V output??? Can anybody help me to make a transformerless power supply???Your help is highly appreciated in our research paper..Thank you!
JJC
Transformerless Power Supply
Saturday, January 12, 2008 2:51:14 AM
Can anyone help me out with 230v ac supply for transformerless with output of 12v 500ma. I appreciate for your help there..
narasimharao
Transformerless Power Supply
Thursday, December 27, 2007 3:36:41 AM
I need 5volt , 20Am DC output without transformer input is 230V,50Hz AC
agg
Transformerless Power Supply
Wednesday, December 26, 2007 4:50:26 AM
Please help me to design a 12v dc 500mA tramsformerless power supply. Any schematic diagram.
Elmer Gambol
Transformerless power supply
Friday, December 07, 2007 7:41:11 AM
Sir, can you help me to make my transformerless battery charger? is there a high current potentiometer? a 15 Am potentiometer? how can I make it so that it will work? Can you give me some suggestion? what will I use instead of potentiometer?
Fernando Prestado
Transformerless Power Supply
Thursday, December 06, 2007 6:47:17 AM
How can I connect 6 ampere or how can make 6 ampere?
vairavel.k.v
Transformerless Power Supply
Wednesday, December 05, 2007 12:22:00 PM
why, the 12v incandescent lamp can not work in this transformerless power supply...
Rajesh Purohit
Transformerless Power Supply
Tuesday, December 04, 2007 6:53:46 AM
Can you help me out with 230v ac supply for transformerless output of 12v 500ma.
Rust
Transformerless Power Supply
Sunday, December 02, 2007 8:32:27 AM
anyone can help me wit my project Step Down Transformer/ power supply having output of 30v 6amp.. thank you so much
Thiha Soe
Transformerless Power Supply
Friday, November 23, 2007 1:03:23 AM
Actually, I would like to have a diagram of 12V DC @ 80mA max power supply. I am very appreciate to get that. Thank you
Rajasekharan C.V.
Transformerless Power Supply
Sunday, November 18, 2007 2:00:02 PM
How can I connect More than 2 Amp/12 Volt
arun
Transformerless Power Supply
Sunday, November 11, 2007 9:48:44 AM
can i use this power supply for ic circuits? if i wan't 20vd and 10amp how to use it ? please mail me
eric afrifa
Transformerless Power Supply
Thursday, November 08, 2007 9:06:21 AM
i want some more explaination about this circuit.. as early as possible.... i.e how it is working. ...how capacitor charges and discharges, its effect on diode. i would be very thankful to you if you can solve my problem
ERIConymous
Transformerless Power Supply
Tuesday, October 30, 2007 6:22:41 AM
i want some more explaination about this circuit.. as early as possible.... i.e how it is working. ...how capacitor charges and discharges, its effect on diode. i would be very thankful to you if you can solve my problem
amit sonwane
Power supply
Sunday, October 28, 2007 2:00:39 AM
I want the regulator 100 Volt dc Power supply pls help me about this data. Thank you Amit
Nemer
Transformerless Power Supply
Monday, October 22, 2007 7:48:24 AM
I need transformerless circuit supply 6V -- 1Am
sesugh hulugh
Transformerless Power Supply
Saturday, October 13, 2007 6:54:10 PM
please I would need a comprehensive circuit diagram on a transformerless switchmode power with output votage of 24V DC and current of 5A.
anonymous
Transformerless Power Supply
Thursday, October 11, 2007 1:13:08 AM
this curcit full weve i?
anonymous
Transformerless Power Supply
Saturday, September 22, 2007 4:31:55 AM
give us the working of this circuit and some equations about it
nirav
Transformerless Power Supply
Friday, September 21, 2007 7:59:20 AM
i want some more explaination about this circuit.. as early as possible.... i.e how it is working. ...how capacitor charges and discharges, its effect on diode. i would be very thankful to you if you can solve my problem......
aji
variable lab power supply
Saturday, September 15, 2007 3:22:58 AM
need different types of variable ps used in labs which has all the fetures including lcd display
Lamina David
Transformerless Power Supply
Thursday, September 13, 2007 10:56:26 AM
plz am in need of your assistance concerning this Transformerless Power Supply as i was given as project to be carry out by me and as i was browsing thruogh the search engine i came across your work and i would like you to give me a compressive note on it including the schematic diagram and function of each components. I will be very greatful to you if you attend to my request on time as i have no much time to waste as i will be defending the project very soon thanks
GONZALO
Some practical tips
Thursday, September 13, 2007 1:41:24 AM
I've working with Xformerless PS for some time. I've made some working circuits too, very similar to the schematic shown, but I must point out some considerations for those trying to build one: Always remember that this design IS NOT ISOLATED FROM MAINS VOLTAGE. No matter how much the output is, some terminals could be very near the live (hot) mains voltage. I guess it's not recommended for begginers. The regulation is based on the capacitive reactance of C1. That is, the bigger the cap, the higher the current flowing through it. This current is always out of phase (90 leading) with the mains voltage. In few words, the current is max when the mains is 0V, and there's no current while V mains is max. For UL approvals, C1 must be complemented with a low value series resistor (between C1 and mains) for surge current limitation, and some other resistor (~1Mohm) in parallel with C1 itself, to discharge it when the P.S. is disconnected from mains (high voltages). I recommend a MOV, varistor just before C1, rated to the local mains voltage, for further surge protection. Real circuits get very hot when not well calculated in advance. These P.S. work by just 'bleeding off' certain amount of power to maintain the required voltage at the load side, zeners and resistors in series with C1 do most of the 'hot work', so must be chosen after knowing very well what current/power they must deal with. For 220VAC, 50Hz, I've used C1=1uF in series with R1=150ohm, BR1 for 1A max, C2=470uF and D1=1N4749 (Vz=24V). Using a 78L05 regulator, I could drive a small relay, a PIC microcontroller and some LEDs (some 40mA at all). Great page, bye!
shailender
14v dc out put 2 amp from solar pannel to charge the car battry
Tuesday, September 04, 2007 3:44:19 AM
please send me the circuit the site is vry use ful and i will try i should go through every day .
venkatesh
UPS construction 230V
Saturday, September 01, 2007 1:30:27 AM
this is very nice website
INDUMATHI.S
Transformerless Power Supply
Tuesday, August 28, 2007 11:32:51 PM
May I know why ripple current is increasing by decreasing AC mains voltage, sir please reply as soon as possible
Engr. May Ann Deypalubos
Transformerless Power Supply
Monday, August 27, 2007 11:12:38 PM
so good to be true. we tried it in our class project but the result was not good. we were just astounded by the many errors we encounteredit was just a waste of time.
Ryan Chandra
Transformerless Power Supply
Saturday, August 25, 2007 2:54:23 PM
Hi, Aaron... Your website is very cool and interesting to those the beginners and hobbyist in electronics as well as the more expertised engineers. Bravo! However, I see that many of the projects in your website are lack of comprehensive technical explanations that leading those who try to assamble it to some difficulties or technical failures. This is represented by the so many questions and comments in the forum. Since you have been hardly ever answering the questions, why don't you give more technical tips or explanations for the circuits? Or, is there any volunteers who can give some exact and precise explanations to resolve the questions instantly? It will help especially those the beginners or students who try to do the project. We'll be glad if the circuits or projects in this site can practically be assambled to result proper outputs, won't we? Regards, Ryan.

(Editor's notes: That's why there's a forum...)

Engr. Stephen John R. Adayo
Transformerless Power Supply
Friday, August 17, 2007 8:54:05 PM
Such a good idea using capacitive reactance as current limitter but the output current is so small and it is insufficient for my load consuming for about 60 mA.. What do you think should i do to make an output current to 60 m.A in a transformerless power supply.. Please send it to my e-mail r_notado78@yahoo.com.. tnx
Ebikipamo .J.
Is it good to use a stabilazer for an inverter to step up the voltage to 220 volts
Thursday, August 16, 2007 8:26:56 AM
am working on the 12 - 120volt inverter circuit,could it give a good output
stanley
Transformerless Power Supply
Wednesday, August 15, 2007 2:15:34 PM
Dear sir,Input Voltage 230 Volts AC Output Voltage 12 Volts DC Output Current 800ma I want this details of Circuit Diagram and Components List. Thank you
jawad
Transformerless Power Supply
Tuesday, August 14, 2007 7:16:26 AM
sir, please help me in making a transformerless power supply for 12vdc with 5amp output and which is isolated from 220vac supply. please send me a circuit diagram or tell me what to do. regards
Austin
Transformerless Charger
Sunday, August 12, 2007 10:28:06 PM
I am particularly very impress about everything in this website.Please Sir, may i ask, is it possible to obtain a transformerless charger from any sub-station using power diodes or any component, for 200amps bartery. If yes, i need circuits schematics and details.Thanks so much.
irfan ul haq
Remot or radio control toy car circuit diagrm and function
Wednesday, August 08, 2007 1:53:18 PM
This is a very good site for students of electrnics
H McKean
24v DC to 12v DC converter
Monday, August 06, 2007 7:32:48 AM
Sir, We have a need for a trim motor for an airplane going from system voltage 24v DC (output) to 12v DC (input) on the motor. We were thinking of just creating a resistance circuit with heat sink and fan. What do you think--have you a design for such a step down? Thank you. H. McKean
anonymous
Transformerless Power Supply
Sunday, August 05, 2007 11:21:16 PM
is this dangerous.... does the AC capacitor ........... can cause electric shock....
shashi prashant
Transformerless Power Supply
Friday, August 03, 2007 1:44:58 AM
Dear sir, I want to make a stepdown power source without transformer please suggest and make circuit diagram. my requirement power source is given below Input 230 V.A.C Out Put 12V.D.C. 1Amps Thanking u.
rambabu
i want design +5v and -5V dc supplies as a output by using 230v AC supply
Thursday, August 02, 2007 10:06:26 AM
i want circuit design for getting +5V and -5V DC ,200mA,and output is regulated to 2% as out put ,input is 220v power supply
Anil Varghese
low current
Wednesday, August 01, 2007 9:55:17 AM
Dear sir I have cellphone charger, which can operate with hand. It is giving 5 volts normally, but very low current / amps. what i have to do to increase the current. thanks and regards Anil Varghese
reynolds
Transformerless Power Supply
Tuesday, July 31, 2007 6:50:14 AM
I need a power suppply but this .must be 24 v Ac to 240 V AC voltage input.current abauth 100 mA .if you can help wrte.
jawad ameer
Transformerless Power Supply
Saturday, July 28, 2007 1:59:07 PM
sir i need a transformer less power supply with i/p=220vac and o/p=12vdc with 5ampere for my lead acid battry charger circuit and also i want isolation from 220vac
anonymous: Bambang Bh
Transformerless Power Supply: Vin=230VAC, Vout=40VDC, I=2A
Thursday, July 26, 2007 10:49:39 PM
Dear Sir, I need a transformerless power supply for I/P=230VAC, O/P=40VDC, I=2A, without transformer. Please help me information about schematic and type of components to be used as without transformer of step-down voltage from 220vac to 40vdc with maximum current 2 ampere. Thanks
ken
Transformerless Power Supply
Wednesday, July 18, 2007 3:05:44 AM
sir,kindly informed about transformerless power supply have an input of 220v ac to 6v dc.thank you.more power.
John Drummondnymous
Transformerless Power Supply
Monday, July 16, 2007 5:14:50 PM
This is a dangerous design and I suspect becomes non-functional fin a very short amount of time. You mention that this design does not have isolation from the main AC power line. I think you should make that comment blinking RED to fully make the point how dangerous this type of connection is. The zener diode absolutely needs a resistance in series with it to limit the current. The design as shown only limits the current into the zener by whatever parasitic resistance is present in the diode bridge. This is a poor design.
timothy
Transformerless Power Supply
Monday, July 09, 2007 1:16:45 PM
please'kindly direct me on the type of componenet to be used as a transformerless step-down voltage from 220v to 12v
raj
Transformerless Power Supply
Wednesday, June 20, 2007 1:53:05 AM
i have 12vdc power supply it only drws 1.2 amp i want increse the amp draw to 30 amp is there any circuit to increse the amp draw
Inalegwu Ameh
Transformerless Power Supply
Tuesday, June 19, 2007 12:03:01 PM
what is the output voltage of the circuit? thank you sir.
RAJIV KUMAR
Transformerless Power Supply
Tuesday, June 19, 2007 2:34:08 AM
I/P=230VAC, O/P=24VDC, I=50ma, without transformer
Anthony Low
Transformerless Power Supply
Sunday, June 17, 2007 9:14:01 PM
Dear Sir, I need a transformerless power supply for Input 220v Output 12vdc to drive a notebook fan of 12vdc 0.2A. Awaiting your earliest reply Thks
victor angba
Transformerless Power Supply
Saturday, June 09, 2007 7:31:20 AM
please Sir, what is the output voltage of the above circuit.
harshala
Transformerless Power Supply
Wednesday, June 06, 2007 7:33:13 AM
sir, i have designed a power supply module which gives 5V DC @ 5 mA without connecting load. but after connecting the load, the current shoots up nearly to 16- 18 mA, without any effect on the output 5V DC voltage. how can i limit this current, and why is this so happenning?? plz guide me....
PeterGib
Transformerless Power Supply
Sunday, June 03, 2007 5:49:08 AM
Require schematic for variable 3V dc to 35V dc and 5Amp?
PeterGib
Transformerless Power Supply
Sunday, June 03, 2007 5:47:11 AM
Require schematic for 18V dc and 3Amp
Terence
Transformerless Power Supply
Thursday, May 31, 2007 11:40:12 AM
Dear sir, I want to know about the 220VAC circuit with out put current about 300mA.
reza
Transformerless Power Supply
Wednesday, May 30, 2007 10:06:39 AM
how can i convert 1 volt dc fuel cell to 5 volt dc?
ss
Transformerless Power Supply
Tuesday, May 29, 2007 7:16:33 AM
I have some Documents about power supply
watchara Ch.
Transformerless Power Supply
Sunday, May 27, 2007 3:22:15 PM
Dear sir,Input Voltage 230 Volts AC Output Voltage 12 Volts DC Output Current 800ma I want this details of Circuit Diagram and Components List. Thank you.
seram baris
mobile charger circuit
Saturday, May 19, 2007 6:40:08 AM
Dear sir, mobile chargers do not have bulky transformer in the input stage instead it uses small transformers at the mid stage.So please let me know about such transformer.Also please suggest me to find such power supply circuits in web.I am in urgent.
Anthony Low
Transformerless Power Supply
Thursday, May 17, 2007 8:59:39 PM
Dear Sir, URGENT... 1. I wish to have a circuit & pcb layout for a 220vac to 12vdc regulated power supply, to drive a notebook fan of 12vdc 0.1aA. Anxiously awaiting reply
e. sherif eissa
Transformerless Power Supply
Thursday, May 17, 2007 2:54:37 AM
dear friend, i need acircuit for interfacing between 110/2200v ac to 5/24 v dc fot the controller,plz help me !!!
SGT ADAMU
Transformerless Power Supply
Wednesday, May 16, 2007 6:38:16 AM
i need authomatic battery charger circuit
M. FAIZ ANWAR
Transformerless Power Supply
Wednesday, May 09, 2007 4:14:51 AM
it is very simple
mohd ghouse
Transformerless Power Supply
Monday, May 07, 2007 11:03:27 AM
Dear sir, I want to make a stepdown power source without transformer please suggest and make circuit diagram. my requirement power source is given below Input 30 V.A.C to 230 V.A.C and Out Put 7.5 V.D.C. 1 Amps Thanking u
adeel
transformerless dc to AC converter
Saturday, May 05, 2007 2:37:24 PM
please some 1 help me to make a transformer less uninteretible power supply send me circuit diagram of its
Rama Mohan
Transformerless Power Supply
Saturday, April 28, 2007 3:30:17 AM
Dear sir, I want to make a stepdown power source without transformer please suggest and make circuit diagram. my requirement power source is given below Input 230 V.A.C Out Put 12V.D.C. 0.8Amps Thanking u
Rama Mohan
Transformerless Power Supply
Saturday, April 28, 2007 2:40:22 AM
Input Voltage 230 Volts AC Output Voltage 12 Volts DC Output Current 800ma I want this details of Circuit Diagram and Components List.
abdoo
Transformerless Power Supply
Tuesday, April 24, 2007 10:40:24 AM
Dear Sir, i want to make a power supply and i have 220v/18v Transformer, what is the best way to get +15v ,-15v &+12v ,-12v& +5v ,-5v. please help me ...........
anonymous
Transformerless Power Supply
Wednesday, April 18, 2007 12:21:47 AM
How to convert 24 volt 5 amp drop down to 12 volt ?
dipol
Transformerless Power Supply
Sunday, April 15, 2007 9:56:15 PM
good thing to know this circuit can i ask also a circuit for 220vac to split 25v (+/- 25v , 0v
Elie Zedeck
Transformerless Power Supply
Wednesday, April 11, 2007 1:35:13 AM
Hi, great & simple diagram. But is there anything that should be done, if I would use it as a heavy duty power suppy ? Let's say, 15 V 50 A. Thanks.

(Editor's notes: Can't happen.)

Imran Rehman
Power Supply
Monday, April 09, 2007 2:37:30 PM
dear sir, i want to make power supply of 5volt and 5 ampere please give me suggestion which type of IC i use for regulated 5volt & 5ampere AND also the 5volt and 1 ampere, which transformer will be used in this power supply & how many volts diode will be used in this bridge rectifier.sir if answer my these question i will be very thankfull to you.bye
Steve_hi
Transformerless Power Supply
Sunday, April 08, 2007 8:47:46 AM
What is the voltage and current out put of this circuit? Thank you
subrhamanyam
Transformerless Power Supply
Friday, March 23, 2007 3:42:21 AM
Dear sir, I want to make a stepdown power source without transformer please suggest and make circuit diagram. my requirement power source is given below Input 230 V.A.C Out Put 12V.D.C. 0.5Amps Thanking u
shakeel ahmed
Power Supply of 5volt & 5ampere
Tuesday, March 20, 2007 11:36:07 AM
dear sir, i want to make power supply of 5volt and 5 ampere please give me suggestion which type of IC i use for regulated 5volt & 5ampere, which transformer will be used in this power supply & how many volts diode will be used in this bridge rectifier.sir if answer my these question i will be very thankfull to you.bye
anandmohan murmu
Automatic power toggle
Friday, March 09, 2007 5:33:08 AM
Dear Sir, i want to make a automatic power toggle system, in which the AC supply of 230 V with 5Am current could be maintain when the power supply is off bye another back-up UPS , so that the power supply could be continue wiyhout the interruption of the power supply in off condition. So, please suggest me, i always be thankful.
M Kubawat
Transformerless Power Supply
Sunday, March 04, 2007 11:33:32 AM
Dear Sir, its really good know your circuit.could u please sugest me to making 240v to 45v-0-45v ( 5-7 Ampere) for an audio amplifier.
S.Laha
Transformerless Power Supply
Thursday, March 01, 2007 6:12:32 AM
Dear Sir, its really good know your circuit. But I would like to know something specifically as: 1. what is the output voltage of the circuit? and is it DC voltage? 2. could u please give me a reliavle transformerless circuit for 12V DC with 1 amper and and 12V DC with 100mA-150mA output from a 240V AC input. I will be really obliged if you please help me. Regards Sanano
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