Are Pure Sine Wave inverters really necessary?


Joined Jan 23, 2018
Really? Why?
Audio amplifier power supplies are full of huge current pulses due to connecting the sinewave from a transformer to an oversized smoothing capacitor.
It is not mostly a power supply issue in audio equipment and some radio equipment, rather it has to do with the harmonic content getting past the filtering that is designed to stop the ripple and noise from standard mains power. In addition, the motors in some tape machines and most turntables do not like the power with all of the harmonic content. And I am aware that some use DC motors and a very few use servo motors. Those are either the very cheap ones or the very expensive ones.


Joined Sep 30, 2009
I run power tools off of the noisypoer from the non-sine-wave inverter and the work wellThat is a disk grinder, a skillsaw, and a hammer drill motor.
You are so uninformed if that is your answer. Those are all things using a "universal motor" and would be just as happy working on pure DC of the correct voltage.
He said, after the Engineering Team put their stamp of approval on a new design,
the new design went to the next department where individual parts would actually be
cut out of the Circuitry one by one, until the TV stopped working.
Then they would put the last part back in place,
and look for other components that could be removed.
Every part was removed that was not absolutely required for the TV to sorta-kinda-function.

This is still common practice today.
That practice was called “Muntzing”, after Earl the Madman Muntz.


Joined Mar 11, 2019
At another forum is a very interesting thread. A person who presents himself / herself as very knowledgeable in electronics stated that in approximately 95% of cases with modern electronics, Modified sine wave Inverters are all you need and that Pure Sine Wave inverters are mostly a gimmick and unnecessary.

Specifically this.......

Since I don't know about this I'm wondering what the consensus among experts here would be?
In my work van I used to use a modified sine wave inverter. Things worked fine. I ended up switching to a pure sine wave inverter when I was upgrading the layout and things ended up running much smoother and quieter. Nothing seems to have been damaged but I can't deny that the pure swine definitely preforms better with my tools.

Deleted member 115935

Joined Dec 31, 1969
Hi @Lumenosity

An interesting thread this,

You are right in that a lot of things can run on very badly shaped "AC" signals, phone chargers being one of the obvious ones.

But conversely, a lot of things are not happy with terrible AC, obvious is things like Audio or even "digital" tv's where a lump a the front is still analog and noise susceptible.

Standards are mentioned,
There are many different standards on radiated emissions,
a lot concern noise coming out on power supply wires,
"cheap" PSUs are compliant on "good AC , but will radiate like mad with a bad AC.

Even thigns like motors, can behave very differently on a bad sine wave compared to a "good" one.

At the end, things are designed and tested ' approved to work with a "standard" sine wave AC,
i.e. its in the standard,
as you say, a lot of things can work with bad sine wave AC, a smaller number work well with a bad AC.

So to answer original question are pure sine wave inverters necessary ?

No most of the time is all one can answer
now if its 95:5 or 80:20 , I could not say,
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