ghauri

Hi all,
I need a circuit containing op-Amp(741) takes square wave as input and convert it into sine wave phase difference is acceptable


please tell

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dknguyen

The square wave has many different frequencies while a sine-wave only has one...run it through an ideal bandpass filter to only have the one frequency remaning for a sine-wave? That would be one insane bandpass filter.

Paul Obrien

A square wave can be thought of as a very large number of ODD hamonics added together (of course it really isn't) so if you build a low pass filter with the cut off well below the 1st odd harminic you will have the square wave convertor.

Hero999

It also depends on whether you want to vary the frequency of the square wave, in fact I don't know if it's possible with a vairable frequency input. You can convert a triangle to sine with a special non-linear converter but it doesn't work with a square wave.

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aanand_44

Hi,

How do produce 1V 100Z AC power supply from the 12V DC?

Jimn

Can some one tell me what a Band Pass Filter and a Low Pass Filter? I'm not a electrical engeneer nor a comp genus. I simply have a need to turn a modified sine wave or step wave into a pure sine wave. I have a 3000 watt modified sine wave inverter, I already have my voltage and the hz are right I just need to change the sine wave so I can operate every thing in my house. Sensitive electronics and such. It's like i have a incomplete inverter. They stoped at the modified sine wave and didn't go ahead and filter it out to a pure sine wave. It's hard for me to believe there's no way to do this. Also is there any way to use a comp or parts from old comps to build something to do this? Any ideas will be appreciated. Thanks

Hero999

In that case, you need an inductor as well as a capacitor, in fact to do a good job of it you need several inductors and capacitors and they'll be pretty bulky too.

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k7elp60

It can be done with two stages of integrators, the first one converts the square wave to a triangle wave, and the second stage converts the triangle wave to a sine wave. If the input frequency varies widely then the output amplitude will vary.
Here is a typical schematic, two identical stages are required

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INTEGRATOR.JPG (5.8 KB, 104 views)

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Hero999

If you want the output ampliture to vary less then you could stick an AGC on the output.

Also note that the duty cycle of the squarewave needs to be 50%, you could run it through a divider but it would half the frequency.

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Nigel Goodwin

Why is everyone answering a two and a half year old dead thread?, don't you look at the dates?.

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Hero999

Valid point. Although it still might be handy for someone else searching through the forums for an answer to the same question.

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pkraju

Hi all,
I need a electronic circuit to convert squre wave into
sine wave using appropreate filters.the coverted wave iwant to transmit through IR.
raju chennai



please tell[/quote]

pkraju

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prasanthbhavana

HAi i made a square wave inverter but i need to convret the out put wave form to modified sine wave or pure sine wave is there any circuit for that please mail me any know about this please it is urgent i need to submit my project on 8th may please HELP ME........PLEASE.........
my mail i d is prasanthbhavana@gmail.com
please mail me about this PLEASE..........

audioguru

If you want a modified sine-wave inverter then you must make a modified sine-wave inverter. You need a different transformer than a square-wave inverter because the peak voltage of a modified sine-wave is 1.414 times higher. It needs a digital logic circuit to make the modified sine-wave.

If you want an inverter with a pure sine-wave then you must make a very complicated pure sine-wave inverter circuit.

If you try to filter the output of a square-wave inverter with a 50Hz filter with a huge inductor and huge capacitor then the resistance of the inductor will reduce the output power. When the load is removed then the inductor and capacitor are series resonant and will short the output.

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