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Generator/Alternator AC Voltage Booster Circuit

Generator/Alternator AC Voltage Booster Circuit

The article explains an alternator power booster circuit which was unveiled by one of the keen followers of this blog, Mr Michael Mbamobi. Let's learn more about the details.

Technical Specifications

There is this circuit I want to show you. I want to show you the circuit through Homemade Circuit or Brighthub.

I didn't see how I can upload picture there. Please direct me I can sent this through Homemade Circuit. Anyway I uploaded the picture here! see the circuit and find out what these our Nigerian Guys are up to. I only hear about this type of device here in Nigeria.

I bought it and disassembled it. With your ability as Engr. Swagatam Majumdar, you can build a better device that can perform this same thing without depending on their own construction.

The folks call this an alternator power booster! It enables small gensets support loads bigger than their coils and feel alright with it without yearning!

I disassembled it carefully because D1, R1, R2, C2 and Q1 are obscured inside a glue like paste.

AC IN is from a small 650VA Generating set which is normally incapable of powering the connected loads.

The diode polarity and the value is not certain but this is its place in the circuit. It got broken while dismantling the glued circuit.

Q1 couldn't be traced either because the print was scraped of by the manufacture.Only its pin#1 and pin#3 responded to the DMM, it read zero like a dead diode, pin#2 does not read with any other pin at all. Pin#4 which is the tab is also unconnected.....just cannot figure out the device or its specs.

The diode D1 is blue in color, small glass type.

Solving the Circuit Request

Dear Michael,

It looks like an AC voltage booster circuit to me. Q1 is probably a power triac, the diode might be a diac DB-3, I am assuming this since it's small glass type and blue in color.
I would be addressing this circuit in my blog very soon....kindly stay tuned for the updates in my blog.

Thanks and Regards.

Circuit Explanation

The circuit appears to be a simple AC voltage booster. The main part which is responsible for supplying the excess power is the high voltage capacitor C1 which charges up with each AC cycle and reverts the power through the switching triac into the connected load.

The load thus gets added power due to the switching high voltage capacitor through the triac.

The triac is probably a BTA41/600A, which responds and switches ON as soon as the diac fires. The minimum voltage required for the diac to fire is around 30 volts.

The above concept can also be implemented with the following circuit which is simpler than the above and is also a lot cheaper.

The capacitor ratings may be modified and experimented with as per the load, and individual preferences.

However this circuit can be used only for heater applications such as irons, heaters, geysers, ovens, toasters, blowers, dryers, hot air gun etc.

Mains Voltage Booster using Two Capacitors and Two Diodes

Please use 1N5408 diodes instead of 1N5402, mistakenly shown in the above diagram.

Video Proof


About the Author

I am an electronic engineer (dipIETE ), hobbyist, inventor, schematic/PCB designer, manufacturer. I am also the founder of the website: https://www.homemade-circuits.com/, where I love sharing my innovative circuit ideas and tutorials. If you have any circuit related query, you may interact through comments, I'll be most happy to help!

69 thoughts on “Generator/Alternator AC Voltage Booster Circuit”

  1. thank you Michael,plz i need this generator booster circuit diagram that can carry AC electric motor at least 1/2 or 1.0 HP, unlike the one that carries only boilers and heating elements . i love your works.Thanks and waiting.

  2. Mr. Micheal (Warbabylon) can help us with the complete circuit. Many of us are yet to get this circuit working. Thank you as you share.

  3. Sir can u help me with my project in school….. I want to know on how to make a power booster…. With the help of you…..sir.. Example. When I have a 3000 watts generated power..I want it to boost into 6000watts or something higher than 3000 watts..

    • Aljonguigue, that’s a technically impossible thing to achieve, you can never boost power. you can boost voltage or current, but the output net V x I will be always lower than input V x I

  4. Hello swagatam, am really glad meeting your post on this. Actually I've seen a generator booster that you can actually use with electric iron and heater. At the moment, am trying to reconstruct this circuit believing I will get my required result of a booster. I have all the components from the above diagram and am about to test it out. Please I have a 104/400v capacitor and a 3.5uf/400v capacitor mostly found in ceiling fans. I hope it will do the trick. Pls am really concerned about the booster circuit and I humbly ask you to throw more light on that. Thanks

    • Thanks nnaemeka, a booster will work only if the input source has enough stock current, if it lacks current then the booster will fail to sustain the load.

      you can use the mentioned fan capacitors for the second circuit…the shown design has been tested by me with a soldering iron and it worked perfectly making the iron red hot within minutes, and I had to switch OFF the supply to prevent the iron from burining.

    • hello ive tried it using the fan capacitor and didnt get a feedback. please what should i do? Also, i saw a picture circuit where 13005 transistor was used with two 100k resistor, one 16k resistor and a ceramic capacitor probally a 1uf/400v. i coundnt get the actual circiut diagram. pls could you help me discover if the above components can be used effectively to boost electrical equipments like electric iron and heater. Thanks

    • hello, I had used PPC capacitor in the second design, I could instant results from it, I am not sure why your capacitors didn't work?

      The diagram at the top is the only one that i have, which was given to be by one of the readers.

    • ..I do not have much idea regarding the working of the first diagram as I am having difficulty in simulating it in my mind…so I can't help you with it…

      • yeah,I like electronics , its most important and usefull thing in the world,but am still getting up in to it, i need an inverters way at an electronics ,I need help Swagatam

  5. Hello once again sir Swagatam..

    can i use this 2 non polar cap. 105J400V and 2 IN4007 instead of IN5408? its not available here.
    Thanks Again..

    • HiPaul, yes it will do…two parallel 1N4007 may not be required, you can use single 1N4007 diodes since the load in your case is small….

      • Dear Swag, thanks for your article. It’s very informative. Please is it’s possible to have a circuit diagram that can work with an Air conditioner. And secondly, what does Booster Capacitor do and how can one be designed.


        • Sixtus, for an air conditioner you will need a transformer, a capacitive circuit might not work. The capacitor in the second circuit add their stored voltages in series to create a doubled voltage at the output

  6. hello sir Swagatam,
    Our grid is 170 volts which is a low voltage and my soldering iron is rated 220 volts 40 watts?
    can this be helpful to power up my soldering iron?
    thanks again sir..

  7. Hello Sir Swagatam..
    Can i use this 2nd circuit for soldering iron that is connected to a low voltage grid?
    Thanks in advance…

  8. Engr.Swagatam
    I commend u for this wealth of knowledge you always made available to anyone who demand of it.my question is; can a variable resistor and additional capacitor be use to vary the amount of current that the load receive.In due course I will upload another circuit of the same function with the one mr Michael uploaded for your input and analysis. this is because this circuit has a variable resistor of 250K

    • Thank you Gabriel,

      Actually I am not sure about the first circuit since it was drawn by assuming the stages.

      in the second circuit the current is controlled by the capacitor values….however this cannot be made variable.

      If you have a more appropriate diagram you can surely send it to me for publication.

  9. Thank you very much!

    A generator output is mainly dependent on the RPM of the alternator, which is governed by the correct timing of the CDI sparks….so may be the CDI sparks are not firing correctly in the ignition chamber of the generator…so perhaps this issue could be identified and rectified appropriately

  10. hello, thanks you…I had tried it successfully on a 25 watt soldering iron but yours is a 1000 watt press iron which might require a huge current….therefore the capacitors must be rated accordingly, may be upto 50uF to 100uF….but should be non polar type….you can try connecting many 105/400V capacitors in parallel for acquiring the results.

  11. hello sir how was your day. my 1hp eletric pump affect my generator when ever i use it to pump water. is there any circuit solution for this to add to my 2.5kva generator to power it.

    • hello olutayo, a 2kva generator should easily handle a 1hp motor, you must first check how much current the motor is trying to draw for the pumping operations, if it's more than 5 amps then probably you may have to replace the generator with a higher rated model.

  12. Sir, still on this matter: if am able to buy one and send it to you will it help to solve this mistry and share the knowledge as you have been doing so kindly?

    In all honesty your kind is very rare.

    I want to say again that am highly impressed and humbled by your openess and willingness to share what you know and guide others like me without attaching a price.

    People ask same questions and you patiently give answers and where you do not know you are humble to admit. Thank you, thank you and thank you again.

    Am learning bit by bit, I loves electronics hopefully someday I will be good and able to help others too.

    Finally, I did write you requesting for a circuit to help me charge my nicd drill batteries. You promised to look into it. Just a friendly reminder

  13. Ok sir. Which circuit should I work on?
    Secondly if it's the second one, does it require a transformer because transformer was mentioned in one of the comments yet I didn't see a transformer in the circuit. Please help me out.

    • I have tested the second circuit with my soldering iron and it worked perfectly…so you can try the second circuit…transformer will not be required, just connect the source supply across the shown input wires, and the output wires can be connected with the load.

      adding more capacitors in parallel will allow you to get more current for the load

  14. From Onyenkwere Chinaza.
    Please I use a 1000W pressing iron and I use a 650VA small generator. Does it mean that this circuit can help me use the iron with the generator?
    If yes which circuit will work. The first or the second?
    In the second is there a transformer involved?
    Forgive me for the many questions, I'm a newbie in this field.

    • No, the above circuits will not increase wattage or power, these circuits will only boost the voltage to double or triple values

  15. I have to agree with my fellow Nigerians that this thing WORKS… Its still kinda strange to me how the circuit could possibly make a 500W generator power a 1500W electric Iron, but somehow it works…perfectly in fact….for heating applications only though. Iron, cooker, electric kettle, .. It goes crazy on any other kind of load like a fridge…. I'd really like to know how this works… The mystery is eating me…

  16. Hi.

    I want to view Posted circuit pictures. How do I view them because they don't seem to appear when I click on them?

    • Hi Mr swagatam please can you device a circuit that can power fridge using
      Triac diac and Micah capacitor please I need it urgently thanks Emmanuel Obayagbona

      • Hi emmanuel, can you please specify what exactly are you trying to achieve…if it's getting more output than the input then I am sorry that's impossible and not feasible….

    • can you specify the input power specifications and the fridge voltage and watt specifications, to be able to understand the situation.

    • Dear Yuzie,

      the above circuits will work only with resistive loads not with inductive loads, and an inverter is an inductive load.

  17. as i posted earlier, i bought one of those power optimizer and i use a 650va generator set (called i pass my neighbour). this gen can not power up a 1500watt electric iron or heater but with the use of the optimizer/ power booster i was able to iron effectively and heat up my water several times and the first diagram looks exactly like d one i have. how i wish there is a way i an send u a snap shot of the components so u take a look at it yourself

    • if you are able to generate 1500VA from a 650VA source by any method then that's a miracle and you must show it to the world, the idea can you a millionaire.

      As for me I have no idea how to do it, as I told you before I am unable to simulate the first circuit so can't help with it.

      a snap shot will not help because that will not reveal the circuit details or the component details of your circuit


    • I am not sure what you are trying do?

      If you are thinking that this circuit will boost wattage then you may be wrong…the circuit will not boost wattage.

      if your iron wattage is too big for the generator then no circuit in this world would be able to make it function.

      the second circuit above will not boost voltage provided the wattage of the load is much smaller than the wattge of the fed input

    • ….sorry I meant

      the second circuit above will only boost voltage provided the wattage of the load is much smaller than the wattage of the fed input

  19. am confused sir u said and i quote "The capacitor ratings may be modified and experimented with as per the load, and individual preferences". what exactly do u mean by this? is it that the 105/400v can be increased or reduced? if that is true what will be the effect of such increase or reduction? also if i have a 600va gen set and i want to use a 1500watt iron on it, will ur modified circuit work? if no what do u advice?

    • yes you got it right, by increasing the uF of the capacitors in the second design you can increase the current or the wattage handling capacity of the circuit

      but you cannot increase the output wattage than the input wattage by using any method, anywhere in this universe, that's not feasible.

  20. pls sir i bought one of those power optimizer as it were called and dismantled it and the circuit looks exactly like the first one uploaded and it was working fine but when i dismantled it, i discovered that the component numbers were wiped off, so my question is this, cant the first one work owing to the fact that it really worked when bought and secondly what is ur take sir. pls reply me and once again thanks for educating me alot

    • Ekeh, if it was working before means it is a good design, but may be you broke something while trying to dismantle it, there must be something that was hidden and secret which you might have broke and that's why it isn't working now….

      I am finding it difficult to simulate the first design so I can't suggest my opinion about it.

  21. thanks for your explanations on this booster. actually I have built the first circuit by mr Michael and I connected the positive to Q1 instead of negative and the device worked without any humming noise but when I reversed my connection to as it is in the drawing above I.e with negative to Q1 I discovered that the device was humming, and also I connected a metre to the output socket the output with out load was 50v but with load 100v. please can you explain these my discoveries.
    more so, instead of a ceramic capacitor can't I use polarised ones because I have 4700uf 25v &1000uf 25v and I have IN5392MIC.
    lastly can I use a diode instead of diac? thank you.

    • to me the first circuit doesn't make any sense at all. C1 is connected directly across the power rail meaning it will only waste power and do nothing.

      even if the circuit works it won't do anything significant.

      the second circuit suggested by me has been tested by me and it really works, but only for resistive loads such as heaters

      4700uF/25V will give you a big explosion.

  22. It will take time…just keep investigating the circuits and the concepts theoretically and practically, when in trouble put up your question here to get them answered appropriately…in this way you will be able to gradually grasp the many aspects and get stronger in the field.

  23. 1N5401 is not a problem, and if you are using a soldering iron at the output even a 1N4007 will work as diodes.

    check the capacitors, they might be faulty.

  24. It would be difficult to troubleshoot without seeing, actually my prototype worked very well, in fact the connected soldering iron became red hot within a minutes time and I had to switch power off to prevent the iron from blowing off.

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