741 comparator - help - Electronic Circuits Projects Diagrams Free

asdad · 9th December 2008, 09:27 AM

I have a triangle wave input (10 Vpp) and a reference voltage of 5 V. The output square wave should look something like this:

I haven't found any simple instructions on how to go about making this but it should be a simple thing. My simulation is in the attached picture.

So the output is not aligned properly with the input... I tried to mess around with the resistors but it didn't do much.
Any hints would be greatly appreciated.

E: The frequence is 1 kHz.

flat5 · 9th December 2008, 12:54 PM

One problem I see is you are sampling into the inverting input so your square wave will be upside down, 180 degrees out of phase.

ericgibbs · 9th December 2008, 01:02 PM

Quote:

Originally Posted by asdad

I have a triangle wave input (10 Vpp) and a reference voltage of 5 V. The output square wave should look something like this:

I haven't found any simple instructions on how to go about making this but it should be a simple thing. My simulation is in the attached picture.

So the output is not aligned properly with the input... I tried to mess around with the resistors but it didn't do much.
Any hints would be greatly appreciated.

hi,
Whats the frequency of the triangular waveform.??

eblc1388 · 9th December 2008, 02:53 PM

Quote:

Originally Posted by asdad

I have a triangle wave input (10 Vpp) and a reference voltage of 5 V. The output square wave should look something like this:

The following circuit should work. Without the MOSFET, the output cannot swing to both rails due to the saturation characteristic of 741 output stage.

asdad · 9th December 2008, 03:27 PM

Okay, I changed it to non-inverting, added a third resistor and adjusted all the resistors. Works great now. Thanks!

flat5 · 10th December 2008, 02:22 PM

If you have the time/patience would you please post the final circuit?
I'd like to know where the new resistor is, etc.

asdad · 10th December 2008, 03:23 PM

Sure.

There's some rise/fall time but it does its job.

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9th December 2008, 09:27 AM	#1
asdad	741 comparator - help I have a triangle wave input (10 Vpp) and a reference voltage of 5 V. The output square wave should look something like this: I haven't found any simple instructions on how to go about making this but it should be a simple thing. My simulation is in the attached picture. So the output is not aligned properly with the input... I tried to mess around with the resistors but it didn't do much. Any hints would be greatly appreciated. E: The frequence is 1 kHz. Attached Thumbnails Last edited by asdad; 9th December 2008 at 03:26 PM.

9th December 2008, 12:54 PM	#2
flat5	One problem I see is you are sampling into the inverting input so your square wave will be upside down, 180 degrees out of phase.

9th December 2008, 03:27 PM	#5
asdad	Okay, I changed it to non-inverting, added a third resistor and adjusted all the resistors. Works great now. Thanks!

10th December 2008, 02:22 PM	#6
flat5	If you have the time/patience would you please post the final circuit? I'd like to know where the new resistor is, etc.

10th December 2008, 03:23 PM	#7
asdad	Sure. There's some rise/fall time but it does its job. Attached Thumbnails