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Simple 48V Inverter Circuit

Simple 48V Inverter Circuit

The post explains a simple 48V inverter circuit which may be rated at as high as 2 KVA. The entire design is configured around a single IC 4047 and a few power transistors.

Technical Specifications

I am a big fan of u....i am a wisp. i need an inverter design with 48volt DC input and 230volt output supply and output power in the range up to 500w.

This inverter will be running 24*7*365 days continuously and should not have charging facility. will u please design the circuit and transformer running on 48v.

Thanks & Regards

Circuit Diagram

The Design

Referring to the shown 48V inverter circuit, the IC 4047 forms the main oscillator stage responsible of producing a totem pole outputs for the connected output stage.

The output stage is made by configuring a 4 individual high gain high power transistors modules, two of them on each channel of the push pull output stage.

The TIP122 are themselves internally configured as Darlingtons which are further attached with TIP35 transistor in the Darlington for generating exceptionally powerful current gain across each of the modules.

Setting up the Oscillator Frequency

C1 and R1 must be appropriately set for achieving the desired frequency as per the required specifications...could  be 50 Hz or 60 Hz.

The shown 48 V inverter configuration is designed to generate a massive 2 kva of output power provided the devices are mounted on sufficiently large heatsinks and the battery rated at 48 V, 100 AH, also the transformer rated at 36-0-36V, 1 kva
For lower outputs, one of the modules could be eliminated from each of the channels.

The BJT BC546 is positioned to provide a reasonably fixed 9 V to the IC in order to keep the IC safe from the high battery voltage and within its specified working voltage limit.


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!

108 thoughts on “Simple 48V Inverter Circuit”

  1. May you kindly assist with a design for 48V DC to 240V AC converter .
    The 48V DC must be supplied by a battery that is solar powered.
    Thank you.

  2. I used CD 4047IC,got 6VAC on pins 10& 11 ,fed it to IRF540 mosfets it drastically drops to around 2VAC and I need 12VAC to be stepped up. What can I do to get 12VAC?

    • at pin10/11 it will show 6V for a 12V battery (50% duty cycle)….where does it show 2V? where do you want have 12V? Please explain with proper details.

  3. Good day Mr Swagatam, we ar appreciative of what u ar doing for human raise. Pls can u show me d diagram of how to connect a relay on inverter so dat when light frm d grid comes it wil be charging automatically. God bles u.

  4. Wil BC546 still work for a 96-0-96 transformer for higher watt say 10kVA?

    And what if I wanna include a charger facility using a relay, can you pls help me out?

    • each TIP35 is rated to handle 25 amps and two of them are connected in parallel on each channel, and the battery voltage is 48V, therefore multiplying, 25 x 2 x 48 gives 2400 watts…I hope you have understood now…

      • I am still not cleared on Something. TIP35 has a maximum collector power dissipation of 90W from its data sheet but from your calculations above, one TIP35 would handle 1200W for 48V which looks contradicting. Pls shed more light.

        Also, what is the function of TIP122 at the power stage. Pls, I need responses

        • It is not 90, it is 125 watts…that is power dissipation rating at 25 degree Celsius.

          According to my analysis, this refers to the maximum wattage the device can handle without an heatsink.

          But the datasheet also mentions that the device can handle 100V at 25 amps across its collector/emitter, which is beyond the capacity of the device without a heatsink, therefore a large heatsink must be attached to enable normal working of the device…

          The TIP122 is added to create a Darlington pair with TIP35 because the input from the IC can be too low to operate the TIP35 directly, you can use any other power device such TIP31 etc…

    • You can determine the gauge of wire to be used by calculating the current from VA/Vpri, then do Current/current density(between 2.2 and 2.4 for copper) to get the conductor size. After getting the conductor size, you can relate it with the AWG standard. Problem solved. ?

  5. good day sir thanks for the post i have learnt from it but sir i stil find a problem in determining the gauge of wire that i need to use for winding both primary and secondary part of the transformer so help me pleasr

    • OLupot, you are not supposed to wind the transformer at home, i wouldn't recommend that, instead you must buy it readymade or get it built by a professional trafo designer.

    • hi Lynch
      the frequency is set with C1 and R1.
      with a fixed capacitor at C1 and a variable resistor at R1, R1 can be adjusted to get the desired output frequency at pin 10 and 11

  6. if I need 50hz or 60hz operation? I ask because I want to build a complete inverter circuit with the arduino so I am trying to work up all the details I seem to forget

    I hope you will fine and enjoying a good life.
    I am your web student, this is a big honor for me. I am thankful to you because I have made many project of your design and published that with your name.
    Now I want to make a 48v or 96v 500Watts inverter to reduce load current for a ling battery backup.
    Will you help me to make this?
    1 The above diagram is used for 48v inverter or there is some change in it.
    2 The Transformer is used in this diagram is 36-0-36 or 48-0-48 volt.

    Regard : Engineer Hafiz Abdul Wahab Mirza

    • Thank you Mr. Hafiz,

      you can use the above diagram exactly as shown, with a 48V/56V supply.

      the transformer can be 42-0-42 or 45-0-45V but not less than this.

      the output will be an ordinary square wave.

  8. what if I dont have many 12v batteries to connect in series for example I just have 2 that would mean the transformer will be huge to manage over 160amps for something like a 2000watt inverter but for example if I have (2) 225ah 12v batteries and I want to parallel them but I need a 2000 watts which I would need 166amps and that transformer couldnt hold in a small case but if I had a boost converter to boost the voltage up to say 60v from 12v then I could use a much smaller transformer thats the point I am trying to make, I still dont know if that makes an sense to you.

  9. OK then I assumed that… The idea behind using a boost converter is for an inverter purpose, I'm assuming also you will say that using a boost converter is pointless or inefficient. I wanted to use it because it would then allow me to buy smaller transformers for example if I wanted to build a 2000 Watt inverter I would need to pull atleast 166 watts from my battery bank also the primary of the transformer would need to be able to manage that amount of current also and that's impractical for a transformer fitting into a regular size inverter enclosure, but if I had a boost converter which I could use an inductor which could manage the 2000 watts but with an output of 60-100v then it would be much simpler to buy or build a transformer of that spec and also it would be smaller and more suitable, if that makes sence to you then let me know…. If so could you design a boost converter to step up a 12dc to 60v or above at high enough wattage 2000 and above

    • No it doesn't make any sense at all, it's like trying to make a car engine by joining 4, 5 motorcycle engines….for your own satisfaction you can surely try it out and see how it performs

      instead of using a boost converter it's better to use many 12V batteries in series

    • outputs are normally connected in parallel to increase current, but for a boost or buck converter it can be simply done by modifying the coil and the power device.

  10. I was thinking about something I dont know if it could happen can I actually parallel 2 or more boost converter outputs together?

  11. Can you explain the use of zener diode as a shunt regulator??.
    And the BC546 too…..how does it regulate 9v for the IC?….R
    The input voltage from the collector of BC546 is 48v right?…
    Tnx.. 🙂

    • 🙂 it is not a shunt, it's an emitter follower, please Google how an emitter follower works.

      yes collector is 48V, but the emitter will be slightly less than the base zener value…8.4V to be precise

  12. Good Evening Engr. Swagatam! ^_^
    Can you describe the uses briefly? :

    1. 4 x 10k resistor
    2. 4 x diodes (except zener)
    tnx for the info…I need it for our interview…in which I chose this type of circuit…

  13. Each time I made a test I told you the frequency so why would you assume I didnt have a device to test even after I told you that I had one….. there are alot of capacitors, it would take very long to go through all just to get one frequency I am not a pro…. anyway I got the 50hz, thanks anyway.

    I used irfz44n I didnt use any driver transistors and then power transistors I used 100ohm resistors to feed the gates to increase power I can just bridge from those same 100ohm resistors to gates of additional fets or should I add more 100ohm resistors?

    • If you have a proper frequency meter then it's just a matter of adjusting the relevant preset or capacitor and measuring the results, that doesn't require to be a pro.

      yes your fet connections are OK. you must add separate resistors for each parallel fet.

  14. my multimeter can do frequency test, i just put both probs onto the output of the transformer and adjust pot and thats the lowest it went, about 119hz

    • if you had a frequency measuring facility then why were you not using it so far?

      anyway increase the capacitor and check again… these are so basic stuffs…

  15. I have a multimeter thats all, I just wanted to know which capacitor to use, I tried a code 104 on a basic setup of a 4047 inverter and I adjusted the 50k preset I used and I got it to 100hz, I just need 50hz

  16. I am getting 5 amps on the positive leg of the battery and 2amps on the negative leg, 0v ac from transformer, battery voltage wen circuit is attached is 12.30v and detached it is 12.67v, I got 33khz from transformer, transistors seems normally warm nothing too much but the transformer get hot i think because of high frequency.

    I got 5v across the output pins 10&11 of ic 4047
    also I am getting 10v dc between center top and each end of the input of the transformer.

  17. ok i just built it I could only find code 473 resistor and I used some tip3055 along with 3 tip106 and 1 tip105 and I only had a 50k pot I used 1 amp diodes accross the transistors and used a half amp transformer at 12v just to test but I got no output.

  18. If its electrolytic would that be a problem because I am wondering if thats the problem on my 4047 inverter…. I can only get that value as polarized so dont know which way to turn it.

    • you can use two nonpolar 0.47uF capacitors in parallel, or simply first try with a single 0.47uF for getting the required 50Hz frequency

  19. So what if I have a DC fan that uses a positive 12 volt but I have a source that is negative 12v could I apply the 12volts to a regulator and connect the fan to the out put and get it to work?

    If yes then I would assume that I have to use a positive voltage regulator to do so and if that's the case why wouldn't I get the same results if I used a negative voltage regulator since I would be directing the flow of current by using the regulator.

  20. Just asking something that I was in a discussion with a friend about, he says negative and positive voltage in relative is actually the samething it's just the direction of flow that makes the difference, would you say that's true? If not could you explain what the actual difference is.

  21. ok all I would have to do is apply 12v, nothing wouldnt have to be changed other than adding a 12-0-12 transformer

    can I use something else instead of the 20amp diodes could I use resistors if so what values could I use, only 3amp diodes are available where I am.

  22. Sir..
    I am unable to find those transistors (9012,9013) . So
    can i use 547, 557.
    ((This is the curcuit of firealarm using electronic buzzer alarm .))

  23. Dear Sir,

    Please upload a very very simple inverter circuit by which I can run a 100 W A.C fan only.
    It's input should be 12 V.

    Thanks in advance.


    Rashid R. Ansari

  24. Hello Sir!! I am a 4th year B.Tech Student Electrical Eng.
    We are trying to make pure wave sine wave inverter using PWM and bubba oscilator for our Final project.also along with it a battery charging and auto cut off circuit would be needed
    We want the inverter to work for day to day purposes.We would be grateful to you if u can give a working circuit fr this.
    thnk u!

    • battery voltage would be around 24 V
      Wattage 500W

      Is this inverter specification alright fr thr project demonstration??
      or should go with a smaller wattage say 100W

    • Inverters can be made right from 10 watts to 100000 watts regardless of their types,
      watts and volts are not specific to inverter designs….so 24V 500 watt is just one of the ranges and can be incorporated for your application.

      100 watt would be better since it would require smaller parts.

      I'll try to post it soon…keep in touch.

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