How to Make a 200 Watt Transformerless Inverter Circuit

A simple 200 watt inverter circuit without a transformer has been discussed in this article, using a 310V DC input. It  is a sine wave compatible.

Introduction

Inverters as we know are devices which convert or rather invert a low voltage DC source to a high voltage AC output.

The produced high voltage AC output is generally in the order of the local mains voltage levels. However the conversion process from a low voltage to high voltage invariably necessitates the inclusion of hefty and bulky transformers. Do we have an option to avoid these and make a transformerless inverter circuit?

Yes there is a rather very simple way of implementing a transformerless inverter design.

Basically inverter utilizing low DC voltage battery require to boost them to the intended higher AC voltage which in turn makes the inclusion of a transformer imperative.

That means if we could just replace the input low voltage DC with a DC level equal to the intended output AC level, the need of a transformer could be simply eliminated.

The circuit diagram incorporates a high voltage DC input for operating a simple mosfet inverter circuit and we can clearly see that there's no transformer involved.

Circuit Description

The high voltage DC equal to the required output AC derived by arranging 18 small, 12 volt batteries in series.

The gate N1 is from the IC 4093, N1 has been configured as the oscillator here.

Since the IC requires a strict operating voltage between 5 and 15 volts,the required input is taken from one of the 12 volt batteries and applied to the relevant IC pin outs.

The entire configuration thus becomes very simple and efficient and completely eliminates the need of a bulky and heavy transformer.

The batteries are all 12 volt, 4 AH rated which are quite small and even when connected together does not seem to cover too much of space.They may stacked tightly to form a compact unit.

The output will be 110 V AC at 200 watts.

 

 

Parts List

Q1, Q2 = MPSA92
Q3 = MJE350
Q4, Q5 = MJE340
Q6, Q7 = K1058,
Q8, Q9 = J162
NAND IC = 4093,
D1 = 1N4148
Battery = 12V/4AH, 18 nos.

 

70 thoughts on “How to Make a 200 Watt Transformerless Inverter Circuit

  1. Have questions? Please feel free to post them through comments! Comments will be moderated and solved ASAP.
  2. why not used a dc to dc boost conversion i.e 12vdc to 350vdc then feed to a H bridge mosfet.can u help me with a switching mode inverter schematic?

  3. I have already published a couple of articles related to SMPS, kindly search them in the given search box (top right corner), you will find them immediately.

    Thanks.

  4. hey swagatam u posted a schematic of a 50 watt inver ter i wann buld it but what is the evivalent of bell 188 transistor….can i get it in nte …. one other thing is it possible u can post a schematic of a 12v car battery charge controller-non dumping taking in power from a wind mill……..charge controller meaning when the battery is fully charged it cuts off charging..and when it drops it starts charging again thanks swag..

    • Hi,

      You can try 8550 or 2N2907 in place of 188.

      I have noted down your request, and will try to design and post the circuit very soon.

      Thanks for the nice request.

  5. Hi, My request is have you heard of a project (football that generate electricity)? pls, can I get the circuit diagram from you?

    • The concept is pretty basic but to design an efficient/effective mechanism would require a lot of practical experimentation and through trial and error.

      I can provide a simple design which hopefully should fulfill the requirement.

      I'll let you know once it gets posted.

      Regards.

    • And they have to be in series. If you want 220V or any Voltage for that matter, simply divide that voltage by 12 and that will give you the number of series batteries you need to connect. So, for 220V, you need 220/12 = 19 Batteries (it is about 18.333 but we don't have fractional batteries).

  6. Hello Swaga, my name is Romeo, Nigeria. Pls i would want you to help me design a circuit that would be able to boost or step up the little current and voltage generated by a small 12V permanent magnet DC motor used as a wind turbine. Let's say the motor generates a minimum of 0.5volt or 1volt DC when the wind speed is very low. The stepped up voltage should be able to charge a 12volts/4amps battry. Please reply fast, this is a project i must complete in very short period of time. Thanks a million times.

    • Hi Romeo,

      The voltage can be boosted but the current will get reduced, the overall wattage of the turbine will be always the same, it cannot be increased by boosting.

      If your motor is able to generate 1V/ 2amps or more only then the voltage is worth boosting otherwise it won't help.

      Regards.

  7. hey….can u design a pure sine wave transformerless fully automatic inverter(with charger)….with 16-19 12V batteries to get a output of about 180-230VAC….
    OR
    can u design a pure sine wave fully automatic inverter with 204VDC(17X12V Battery) with charger and overload protection,low battery shutdown….?

  8. hy mr swagatam..

    my name is mukhsin from indonesia

    would you help me to give me an advice how to build inverter 1000 watt Pure Sine Wave 12vdc to 220 vac to start up the water pump?

    thank you very much

  9. Hi Swagatam

    I had built ZVS induction heater with 2 mosfets a year ago, which resonate at high frequency giving 40-70V, 70A, 100% pure sine wave. The output volts, amperes and frequency can be controlled.

    What I am considering is to employ a transformerless circuitry to step up the output to 220V. Can you help me in this regard?

    • Hi Abu-Hafss,

      I have no idea about how induction heater circuits work…if you have built one by your own that's a great achievement…I would request you to provide more details about your experience with the project, if possible with diagrams…I would be most glad to present it in the form of a new article.

  10. Dear Swagatam

    I had built that simple induction heater based on information given on following link:

    http://www.rmcybernetics.com/projects/DIY_Devices/diy-induction-heater.htm

    After seeing this site, if you still want me to share my project's photos then please give me some time to prepare them. Just confirm me if I prepare them or not.

    By changing the Capacitors value and Center-tapped coil, we can change the frequency and volts. By changing the choke turns we can change the amperes. Since the circuit is very very simple, I am considering to use some circuit instead of a bulky transformer.

    • Dear Abu-Hafss,

      Thanks!

      It's an interesting article however not very useful because the project requires external costly cooling agents for controlling coil temp, initially i got too excited, but then realized the drawback.

      Anyway what are you intending to make by boosting the voltage, are you trying to make a compact inverter out of this design??

    • The coil can be made with thick solid copper wire. But in that case the unit could not be used for long time. A better alternative is thick stranded copper wire.

      Currently, I am trying to make a compact inverter.

    • Yes you are right, using a copper mesh or bifilar copper wires could solve the problem.

      For making it into an inverter you would have to wind the coil over a ferrite transformer, it could be a matter of some trial and error…..the input could be around 10-0-10 turns of 0.2mm copper wire, while o/p around 300 turns inside a 27mm E-core type trafo asssembly….you can try it out and check the results.

  11. Since batteries are expensive here (30 bucks a piece) and transformers come with their own share of problems (bulkiness, sometimes hard to find), why not adapt the transformerless concept to other inverter designs?

  12. Dear Swagatam,
    Thanks for the reply!!!
    I have designed 12v power supply as per your circuit to drive ccfl bulb and 12vdc fan.Ccfl bulb inverter board input is 12v 5ma and the fan input voltage is also 12v 100ma,but
    both will connect the zener across voltage shown in multimeter is 7volt.But i remove the fan connection the zener across the multimer shows 12v.So how to give 12v for both components.

  13. I have a question about some resistors .This resistor value ( before the diod 1 (1N4148 )) 100 or 100k ..which one ? and what's the value of resistor ( before the Q1 transistor ) and last question , 0.2 ohm or 0.2 k ohm which one do we need to value ?

    • Hi RM,

      initially keep the input disconnected from the oscillator, and keep it grounded, also keep the output without any load.

      next connect small 100mA bulbs in series with the +/- lines, switch ON power….you will find the bulbs illuminated….now simply adjust the 1k preset until the bulbs just shut off…the quiescent current is set…..the bulbs can be now removed, input restored with the oscillator… and the circuit can be used in the normal way as shown

    • Daryl, i do not have a simulation or test results, but the circuit will 100% work, because the concept is very clear.

      the circuit is actually a 120V/300watt amplifier circuit, instead of audio we feed a 60Hz squarewave at the input and we get 120V 200 watt at the output, the load here is our appliance instead of the speaker



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