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Transformerless Power Supply Using MJE13005

Last Updated on by 100 Comments

The following article presents a very simple low current mains operated transformerless power circuit using an inexpensive MJE13005 transistor and few other passive electronic components.

As can be witnessed in the given circuit diagram, the design is extremely straightforward.

How it Works

Transistor T1, which is a high voltage NPN transistor MJE13005 forms the main active component in the circuit.

Rest of the components are positioned just for supporting the conduction of T1 and for the required stabilization.

The circuit can be understood with the following points:

Mains input is fed across D2 and the negative line of the circuit.

D2 rectifies the mains AC, while C1 filters to some reasonable levels.



R1 drops the current to tolerable limits in order to provide the required base bias for T1.

C2 provides further filtration to the voltage generated after R1.

D1 clamps the base voltage at the base of T1 to 24V, such that the maximum output voltage can never exceed this limit.

A mirror voltage which is always equal to the zener value is generated at the output, however the presence of R2 enables the response to become variable.

The adjustments made through R2 effectively varies the zener voltage right from zero to the maximum value, that is up to 24V.

Thus the obtained output becomes variable from zero to 24V.

However since the voltage is acquired across the emitter/ ground of the transistor, the current gets restricted to very modest levels, at 25mA to be precise.

The zener voltage though may be increased to any desired limits.

WARNING: THE WHOLE CIRCUIT IS NOT ISOLATED FROM MAINS AC, THEREFORE IS EXTREMELY DANGEROUS TO TOUCH WHILE IT'S UNCOVERED, AND POWERED CONDITION

Parts List

R1 = 100k
R2 = 10K POT
C1 = 4.7uF/300V
C2 = 10uF/100v
C3,C4 = 100uF/30V
D1 = 24V, 1WATT, ZENER DIODE
D2 = 1N4007
T1 = MJE13005






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Comments

  1. thank you, i will do as you said
    please explain what you mean by isolated from main input ,i know i’m asking too much sir.

    Reply

    • it means AC 220V will be floating across the whole circuit and may produce a lethal shock if touched in switched ON condition

      Reply

  2. sir, what i’m intended doing is to use this circuit to set low battery cut and full charger cut off for one of your charger I’m yet to build . I hope is clear now, but you have not responded concerning the video I sent to your mail. God bless u for your response so far

    Reply

    • Youngking, Please do not use the above circuit, instead try the last circuit from this article:

      https://www.homemade-circuits.com/1-watt-led-emergency-lamp-circuit-using/

      ignore the 8550 transistor, the LED, and the 1N4007 diode, and use the output which is available across the 1K resistor.

      Do not use 2uF at the input instead use a 0.33uF/400V

      Remember all these circuits are extremely dangerous since these are not isolated from mains input, proceed at your own risk.

      Regarding designing a transformer I am sorry, I cannot suggest much, because I have no experience with practical transformer designing, whatever I have published here are all referred from other sites or magazines.

      Reply

  3. good day sir, sir what i mean is concerning your twin/split charger that has change over which require variable power supply circuit to set the low battery cut off and fully charge cut off. now my question is as follows
    1.can i use this transformerless variable power supply circuit to set this charger.
    2.what component can i use to monitor this circuit when varing from 0-24v.
    pls i’m waiting for your response
    thanks

    Reply

    • Youngking, do you mean to say you only want to power the IC circuit with the transformerless power supply and charge the battery from an external source through the relays?? I am not sure what you are trying to suggest? please clarify elaborately

      Reply

  4. Good day sir ,I want to construct 1000watts inverter transformer the out put is the primary 220v and the input is 12v which is the secondary side. I want u to check if my calculations are correct
    1000/12= 84amps
    Secondary current 84
    Secondary volt =12-0-12 equal to 24volt
    Primary volt= 220v output
    Output frequency=50hz
    Finding the core area- 1.152*√24* 84=387
    Calculating turns per volt= 1/(4.44*〖10〗^(-4)**387*1.3*50)=8.92
    8.92 is my turns per volts
    Number of turns for primary– 8.92*220= 1962.4
    Number of turns for secondary – 8.92*24=214.08
    Pls sir I will appreciate if you clear me on this.
    Thanks GOD bless you

    Reply

    • Youngking,

      If you have put the formulas correctly then it should be correct, I don’t remember the formulas so it would be difficult for me to confirm the results.

      Reply

  5. sir can this circuit be using to set your twin/split charger if not what are the modification. i’m waiting for ur response thanks

    Reply

  7. please prince of electronics Swag, I request you to design me a transformerless power supply 12v dc , 5amps

    Reply

  8. Hi Swag
    I have a question on the circuit diagram, if we measure between collector and ground we should get rectified mains, not so? The zener diode only affects the base of T1. If that is correct wouldn’t we expect mains voltage at the output once the base is forward biased?

    Reply

    • Hi Sidingilizwe, the collector ground voltage will be apulsating DC at around 300V if the filter capacitor is good.

      The zener diode forces the transistor to allow only around 24V DC at its emitter side which is turned into pure DC due to the presence of C4.

      Reply

  12. Hello sir,
    I read all comments , and in several post, some ask you if it is possible to increase output current .
    Your answer was NO ! , just because of non isolated circuit design. (Very dangerous)
    Now, my search is about 5V – 250mA output, but also i don't need to be isolated. ( full non touch possible , sorry i don't know how translate)
    I look lnk306, viper22a , etc , but not really cheap, and hard to get full work well.
    So can you help me , or drive me to a way to get what i wish.
    Thanks
    Best regards.

    Reply

  13. Hello,
    I'm sure you know this is very late asking a question regarding your design. Hopefully you will read this.
    I see your parts list, but can you give values for the wattage for…. R1. Will this need adjustment in case of modifying the output, I've, if output is required at 12v, will RI wattage be different?

    Many thanks

    Rich

    Reply

  14. Hello,
    One question regarding your schematic : would it work with only the phase 220VAC line and no neutral.
    I'm working on a power supply for a small radio module to controle light switch. behind the light switch I don't have the neutral line.

    Reply

  15. when i gave supply to the circuit c1 heated up and exploded, should i change the value?
    please reply soon.

    Reply

    • Bro I won't recommended this circuit for SMD because SMDs are costly and we require foolproof design, so better go for a 12V SMPS adapter available readymade.

      Reply

    • Hi Vikram, use the following circuit, the above will not work:

      https://homemade-circuits.com/2012/03/how-to-make-simplest-1-watt-led-driver.html

      put all the LEDs in series and join it with the output of this circuit

      Reply

    • Dear Bharani,

      According to me an SMPS would be the correct option choice for driving a high watt LED.

      you can easily procure a readymade 24/1amp smps unit ad power your LED through

      it….smps amp is not crucial as long as the voltage does not exceed above the led specs.

      Reply

    • Avik, you can use the above circuit and add an overboard transistor across the existing mje13005 for boosting current to the required levels.
      I'll try to update it soon here.

      Reply

    • For charging batteries you will have to employ an smps circuit, other forms won't be safe as these may not be isolated from mains AC and also not capable of producing higher current outputs.

      Reply

  27. hi sir thank you very much, i just ask you about the current ? , can i get 1A for exemple, thank again you are doing a good job sir

    Reply

    • you can use the following circuit:

      https://homemade-circuits.com/2011/12/make-hundred-watt-led-floodlight.html

      just replace the components by calculating them with the given formula.

      You will need an external smps to drive the above circuit

      Reply

  30. SIR,

    i tried to triger BT 139 using 4017 ic out put stage(50ohms 1w resister used to it) but resister blow up.so please let me know how to triggering it (i want to make knight rider circuit using 230V bulb)please

    thanks

    Reply

    • connect the triacs in the following manner:

      WITH THE TRIAC NUMBER PRINT FACING YOU:

      right leadS to the outputs of 4017 via 1K resistors.
      center lead to one of the bulb wires, the other bulb wire to mains any one point.

      left lead of triac to circuit ground, and also other point of mains to circuit ground (common)

      Reply

    • sir,

      i couldn't tell u that i used (https://homemade-circuits.com/2011/12/cheap-yet-useful-transformerless-power.html) power supply with changers that zener diode was replaced with 5.1V 1W(my kinght rider circuit work with 5V supply as my creation).so how many wattage of 1K resister for trigger bt139 or bt136

      please guide me

      thanks

      Reply

    • sir,

      also tell me that suitable triac number for about 150W 230V bulb instead of bt136 or bt139 please

      thanks

      Reply

    • THANK YOU SIR,

      I'm looking for your article,when it up load please send link as reply for this

      thaks thank you very much

      Reply

  31. sir,
    can i use this power supply to knight rider circuit (4017 IC)? will it be work? if not work please let me know with any modification of power supply circuit

    thanks
    Priya

    Reply

    • Yes the above circuit should work…. if you have problems you can try the following one:

      https://homemade-circuits.com/2011/12/cheap-yet-useful-transformerless-power.html

      Reply

  32. Hi swagatam, i want to isolate the circuit from mains .so my idea is to add a circuit from your earlier posts (induction type battery charger) with a small centre tapped ferrite transformer.will it work? If not any other methods plzz.

    Reply

  33. SIR, I tried to build simple night rider circuit using 4017 ic.powered by transformer less dc supply.but it did not work properly so i tried again using battery then it worked.so please let me know about how can i do this using simple transformer less power supply.

    thanks

    Reply

  35. thank you so much.. by the way, our circuit is a full wave bridge type rectifier.. can we use 1N4001 for the bridge diodes? and do we need to add resistors? thanks again..

    Reply

  36. hi.. i am a second year engineering student and i have a project in school. i have to use a 15V, 2 ampere transformer to make a power supply which has an output of 15V.. we already tried twice but the capacitor keeps on exploding.. can you please help me? thanks..

    Reply

    • thank you so much.. i am about to build a bridge type rectifier.. can a still use 1N4001 as bridge diodes? and should i add resistors in the circuit..? thank you so much for yor time

      Reply

  37. Dear Swagatam,

    Can I use MJE 2955 (PNP) transistor to increase the current output? Plz check this point & confirm.

    T.RAY
    KOLKATA

    Reply

  40. Sir, It is very good idea and design. If I need 0-110V, I just change only zener is 110V, anything else not change.

    BB

    Reply

  42. hi swag t. good circuit. how to get 3v with mains isolation like moblcharger. & is it ferrite cored tiny transformer in cfl, psu circuits act as isolator. thanks

    Reply

    • Thanks!

      In the above suggested circuit mains isolation won't be feasible….

      yes it's the presence of the ferrite transformer which does all the isolation.

      Reply

  44. "D2 clamps the base voltage at the base of T1 to 24V, such that the maximum output voltage can never exceed this limit."

    It is D1 not D2, correct ?

    By the way your circuits are just awesome. Simple and Elegant …. Keep going…. 🙂

    -ElectronLover

    Reply

  45. Dear Swagatam

    Can this circuit be used for your "Surge Protected Cheap Transformerless Hi-Watt LED Driver Circuit"or 1watt led driver.

    Is it possible to drive more than one 1watt led.

    what will happen if I add 1uf/400v Capacitor at the input side.

    Regards
    T.Ray

    Reply

    • Dear T.Ray

      The present circuit won't be capable to drive 1 watt leds due to its low current specs….I thing the current capacity can be enhanced by adding an outboard PNP high voltage transistor across the collector/emitter of the MJE13005 trasistor……it seems it would do work.

      Reply

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