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12vDC to 220v AC converter

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Ziddik

Member
i got this circuit from net and the author of this circuit says it could convert 12v DC to 220v AC!!

**broken link removed** so my question here is can i use it to run some ordinary home appliances such as TV,water pump..etc? The main advantage of the circuit is it uses only an ordinary center tapped 2X10V Transformer!! Any idea?

Here is link to the original page https://electroschematics.com/220/12v-dc-220v-ac-converter/
 

carbonzit

Active Member
Will it work? Maybe. If it works at all (that looks suspiciously like one of those notoriously bad electronics sites), it'll work if
  • whatever you plug into it doesn't use more than 150W
  • whatever you plug into it doesn't mind square waves instead of sine waves (the waveform generated by the 4047 astable multivibrator is a square wave)
  • you don't mind horrible or non-existent frequency regulation (using a trimpot to adjust the frequency between 50-400Hz is not a way to generate a stable frequency)
 
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carbonzit

Active Member
If you read the many other threads here about constructing inverters, you'll find that it's a losing proposition.

You can buy a ready-made inverter much, much cheaper than you can build one. They're commodity items, made in China, that can be bought practically anywhere in the world.

They're complex devices and not easily designed or built by DIYers.
 

Ziddik

Member
i know it cZ, but building our own inverter and seeing it works is incredibly fun! Ain't it? I recently built a 5.1 home-theatre system for a very cheap (around 40$) cost and it works incredibly amazing with high and clear output with a USB/SD module and a tiny remote-controller! It has 3 functions (selector switches) For DVD/USB/COM-AUX and i also designed a delayed relay across the output of sub-out" so its a perfect design without any disturbing noise/hum, now this "inverter" must be my next project thus pls pls give me some positive replays..
 

ericgibbs

Well-Known Member
Most Helpful Member
hi Ziddik,
Square wave inverters are not too difficult to make for light loads, sine wave types are more difficult.
 

ericgibbs

Well-Known Member
Most Helpful Member
sorry but i must ask it.. What is the differnce between a square wave and sine wave? ..assuming i have to learn a load!

The circuit you posted is a square wave type, you can see that its driven from a square wave from the 4047 outputs.

The normal Mains supply is sinusoidal, some inverters try to imitate the sine wave.
 

Ziddik

Member
okey i learnt a little bit about square and sine waves from net.. Now all i want to know are..

1.can i even light up a 2x60w bulbs using that circuit

2.Any wrong in the schematic which i posted above?

3.Is it possible to replace its transformer with 12-0-12V 5 amperes transformer?

4.Any replacement available for both the transistors(i got a plenty of mje13005,13003..etc)? Moreover its a step-down transformer in opposite!! Is that normal?
 

audioguru

Well-Known Member
Most Helpful Member
The transistors and transformer are rated for a maximum current of 3A which is an output of only about 30W (plus 6W of heating).
The output voltage will be too high when the battery is fully charged and/or the load current is low.
The output voltage will be too low when the battery is running down and/or the load current is high.

The circuit has nothing to stop voltage spikes that will destroy the IC ands the transistors.

Most electronic products operate from the peak voltage of a sine-wave that is much higher than the voltage of a square-wave.
 

Reloadron

Well-Known Member
Most Helpful Member
Most Inverters produce what is called a modified sine wave (which looks nothing like a sine wave) but anyway here is a link to one such version. The link uses a uC (Micro Controller) but note the similarity between the circuit you posted and the linked circuit.

This is a link to pretty much the same circuit by the same author using everyday discreet components to drive the transformer.

The first link provides a good series of wave forms.

In most cases it is easier to buy than roll your own but for those who wish to build their own you will see pretty much all versions look the same as far as two transistors of sorts driving a transformer. While some critical systems need a true sine wave a device like a light bulb really doesn't care.

<EDIT> Something to keep in mind as mentioned is for every 100 watts out you will draw about 10 amps of 12 volt power. Keep that in mind for the feed wire from the 12 volt source and power to the MOSFETS. Also, you gonna need a big battery! </EDIT>

Ron
 
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Reloadron

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Most Helpful Member
Mr. AudioGuru person:
Most electronic products operate from the peak voltage of a sine-wave that is much higher than the voltage of a square-wave.

Huh?

Most of the gizmos down here work off the RMS value of the sine wave so it must be a Canada thing. :)

Also if you look at the original posted circuit the transformer has a 20 volt, 10 volt center tapped transformer being run on 12 volts. In the case of a square wave Epk = Erms. While I agree it is not exactly a work of electronic art it will light a light bulb which likely won't care how close to nominal the voltage is. Will it work sophisticated electronics that require a sine wave? No, but will work.

My bad, assume 50% duty cycle.

Ron
 
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audioguru

Well-Known Member
Most Helpful Member
Mr. AudioGuru person:
Huh?
Most of the gizmos down here work off the RMS value of the sine wave
No.
They work from the rectified and filtered DC peak voltage that is 1.414 times higher than the RMS voltage. But the peak voltage of a square-wave is exactly the same as its RMS voltage.

Also if you look at the original posted circuit the transformer has a 20 volt, 10 volt center tapped transformer being run on 12 volts. In the case of a square wave Epk = Erms. While I agree it is not exactly a work of electronic art it will light a light bulb which likely won't care how close to nominal the voltage is. Will it work sophisticated electronics that require a sine wave? No, but will work.
I said that many electronic products will not work from the square-wave inverter. Of course simple incandescent light bulbs will work becasuse the 10V to 12V difference of the ttransformer and battery covers the loss of voltage in the darlington transistors.

The simple circuit is missing voltage regulation so the output voltage will be too high and will be too low sometimes.
 

Reloadron

Well-Known Member
Most Helpful Member
Now, now AG, When you say:

Most electronic products operate from the peak voltage of a sine-wave that is much higher than the voltage of a square-wave.

I figures where you plugs them in. My plugs down here have 120 VAC RMS 60 Hz. My electronic products operate from 120 VAC RMS. Now once they are plugged in other things happen? Not much doing with my everyday desk lamp, sort of boring, just a tungsten filament bulb. My computer operates from 120 VAC RMS, but I am pretty sure there are things in it that change it around, like magic stuff. Those are products! :)

You also know I am just giving you a hard time. I pretty much agree. The circuit is a simple circuit, yes it lacks regulation but again it is a simple (like real low parts count) circuit. Will it work? Yes! IS it a work of art? Hell no! I can't hang around and give you a hard time. I get up for work around 3:30 AM. However, give me a few years and I'll be retired too! :)

Have a good one....
Ron
 

audioguru

Well-Known Member
Most Helpful Member
An extremely simple square-wave inverter is not made because it cannot power many modern electronic products like radios, some TVs, amplifiers and motor speed controls.

Of course it can power simple incandescent light bulbs and heaters.
 
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