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13th May 2010, 18:20 #1
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Urgent!!!
hi..can anybody tell me how to convert a sine wave form into a square waveform by using opamps(IC741 specifically)....its my term project and i have just half a week left to submit it so plzzz hurry and reply..plz be elaborative and include diagrams if possible..thanks.regards

13th May 2010, 18:36 #2
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Re: Urgent!!!
Dude, no one in this forum will do someone else's work. We only HELP. It is your work so you have to do it yourself.
However I will help you.
In order to convert a sine wave into a square wave you only have no use an Opamp (like IC741) using a noninverting amplifier circuit with a very large gain.
The very large gain willl make the circuit saturate quickly, transforming your sine into a square.
This site has exactly what you need:
http://www.wisconline.com/Objects/V...spx?ID=SSE7906
You should use the "noninverting amplifier", and not the "inverting" for 2 reasons:
1) It does not invert the sinal (I supose that's what you want)
2) It has very high input impedance (which is always good)

13th May 2010, 18:36

13th May 2010, 19:24 #3
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Re: Urgent!!!
hmmm..yeah that'l do it..thanks..ur a life saver!..:D

13th May 2010, 23:16 #4
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Urgent!!!
Or just use the opamp like a comparator  no feedback.
KeithI started life with nothing and I've still got most of it left. (Seasick Steve)

14th May 2010, 16:20 #5
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Re: How to convert sine wave into square wave using opamp
Or just use the opamp like a comparator  no feedback.

16th May 2010, 22:03 #6
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Re: How to convert sine wave into square wave using opamp
ohk thank you for your feedback . i was actually able to "test run" my circuit in the lab..but you see there's now a tiny miny BIG problem..i am now suppose to convert my square wave output into a trangular wave.:(..Now how i do that?..and also to convert a sine wave into square wave using IC741 opamp?...and my project is now worth 50% weightage of my total course..what a misery!!

16th May 2010, 22:03

16th May 2010, 22:31 #7
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How to convert sine wave into square wave using opamp
You need an integrator.
KeithI started life with nothing and I've still got most of it left. (Seasick Steve)

17th May 2010, 01:45 #8
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Re: How to convert sine wave into square wave using opamp
Keith is right, you need an integrator. Check this out:
http://www.wisconline.com/objects/V...spx?ID=SSE5303

17th May 2010, 02:33 #9
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Re: How to convert sine wave into square wave using opamp
that was an excellent help sir!!...i really appreciate it..and the slide show well that was so elaborative and easy to understand:)..thanks once again.you ppl are great help..kkep up the good work:D

17th May 2010, 09:23 #10
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Re: How to convert sine wave into square wave using opamp
hey!! hey.!!:D..i made the project and m just a day away from showing it to my teacher..guys ive made the integrator and adjusted the but i didnt have any idea what i was doing actualy..i read it somewhere that if you change the resistance and capacitance you can adjust the wave into traingular wave but what i want to ask is that is there any specific easy to understand "formula" for voltage output of an integrator?..not that one that includes an 'integral' type of stuff but a simple universal formula so i can easily understand it and make my teacher understand it as well:)..thanks waiting for ur feedback

17th May 2010, 09:23

17th May 2010, 09:42 #11
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How to convert sine wave into square wave using opamp
Unfortunately an integrator integrates, so it is difficult to avoid integration in the explanation:
http://en.wikipedia.org/wiki/Operati...ing_integrator
In simple terms, the output will decrease (because it is inverting) at a rate determined by the resistor and capacitor at dV/dT=Vin/RC so if you had 100k and 100nF and a 5V signal, for example, the output would change at the rate of 500V/s.
Keith.
Added after 3 minutes:
The simple explanation, by the way, is that the opamp keeps the inverting input at zero volts, so the current in the resistor is Vin/R. This current must go through the capacitor and the equation for a capacitor charge (Q=CV), when differentiated gives I=C.dV/dt. So, dV/dt=I/C = Vin/RC. The minus sign appears because of the dire4ction of the current in the capacitor, resulting in Vin/RC.
Keith.I started life with nothing and I've still got most of it left. (Seasick Steve)

17th May 2010, 10:42 #12
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Re: How to convert sine wave into square wave using opamp
Perhaps TANSAH wants to see an integral explicitely in the formula.
Therefore, read this explanation for an intergator circuit (without signal inversion):
* Voltage across a capacitor: Vc=(1/C)∫idt with i=Vin/R (due to virtual ground at the inverting opamp terminal)
* Thus, Vc=(1/RC)∫(Vin)dt.
* For Vin=const. this leads to Vc=(1/RC)*Vin*t (>>linear ramp prop. to time t).
Perhaps this helps.

17th May 2010, 18:16 #13
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Re: How to convert sine wave into square wave using opamp
yeah i think i have understood most of it..thanks once again ppl:)
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