I use an inverter (600 W) to convert from DC 12 V to AC 220 V 50 Hz, but the wave output from the inverter is a modified sine wave, which causes problems when operating some electrical appliances (high temperature, noise, etc.) I also find it difficult to obtain a current inverter that produces a pure sine wave so I am working on converting the resulting wave from a modified sine wave into a pure sine wave using (a coil or resistor) and a capacitor, but the wasted energy when using the copper coil is as large as it is greater if you use a resistor.

  • \$\begingroup\$ Welcome! "I also find it difficult to obtain a current inverter that produces a pure sine wave" I find 158 to choose from on Amazon alone. There are many other vendors as well. If you do intend to filter out the harmonics of your existing inverter, have you hooked up your oscilloscope to the output (be aware of voltage rating on your probes and scope input) and tried to simulate it in your simulator of choice? \$\endgroup\$
    – winny
    Commented Aug 15, 2023 at 11:43
  • 1
    \$\begingroup\$ Actually using an inductr/capacitor filter WON'T generate heat -- it will filter, but there is nothing in it that absorbs heat. Basically, it prevents the higher harmonics from passing though the filter. \$\endgroup\$
    – jp314
    Commented Aug 15, 2023 at 15:30
  • \$\begingroup\$ Please edit the question and add a list of the loads you are trying, and what are the symptoms. Modified sine wave is a problem with induction and some synchronous motors and... not much else in my limited experience. \$\endgroup\$ Commented Aug 15, 2023 at 23:57

2 Answers 2


The simplest solution is to rectify the output and wire it to a synthetic sine wave inverter.

I'm not actually kidding.

Given that this is a fair amount of circuit design (even with pre-baked (single IC) solutions available, a complete design still requires a handful of transistors, capacitors, several diodes, and a couple dozen resistors, and all must be placed and wired correctly on a PCB), perhaps you can begin to appreciate how bad a passive solution must be.

I can put it another way: if you had enough copper and iron for a passive filter network (which might still not even be compatible with the inverter as such; it might not start up into such a load, or other characteristics will be lacking as a tradeoff) -- why wouldn't you simply sell it for scrap and buy a better quality inverter?

More seriously: the most likely candidate would be a ferroresonant transformer. It's not obvious to me whether a modified sine inverter would be at all happy driving one of these, but suffice it to say, a 600VA unit weighs more than a few kg (hence, is literally worth a modest amount as scrap). They run hot, and are rarely used and therefore expensive to buy -- if you can find one in your market at all.


you try using sine wave circuit gs002 it only consumes 0.01a, if it's a homemade H-bridge it also consumes very little power


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