hi all,
i need help in opamp usage,
I'm using this LM741 in single 5V supply..The purpose is to shift the DC level of input signal.
If the signal is 5Vpp wit DC value at 0V(from -2.5 to +2.5V).
I shd shift this signal to +ve side b/w 0 and 5V with DC at 2.5V..
Is this possible?

if not, is there any other way to do this,
pls help

thanks in advance,
A

 

you could use a simple summer circuit. You could sum a dc signal in with your data signal.

A simple voltage divider should give you the voltage that you want.
The below link may help you:
http://www.allaboutcircuits.com/vol_3/chpt_8/8.html

 

You'll need to use a different op amp, that is way under what a 741 can use for power supply. A LM324 might work.

 

You won't get there using a 5v supply with an LM741. If you're lucky, you might get 1v peak to peak output with a 5v supply. LM741's were the greatest thing since sliced bread, when they were introduced some 40+ years ago. They are still around because professors like to punish their students with them.

Increase your Vcc to 10v, or use an opamp that has rail to rail inputs and outputs, like an LM6132.

 

You won't get there using a 5v supply with an LM741. If you're lucky, you might get 1v peak to peak output with a 5v supply. LM741's were the greatest thing since sliced bread, when they were introduced some 40+ years ago. They are still around because professors like to punish their students with them.

Increase your Vcc to 10v, or use an opamp that has rail to rail inputs and outputs, like an LM6132.

I hear that! I am one of those students!
Our lecturer had marked vcc and ground pins wrong on our schematics and in the space of a few minutes a whole class's worth of opamps were blown!

 

There bye allowing him to buy new op amps, or get closer to that goal.

 

A LM324 might work.

Nope. Voh for an LM324 is Vcc-1.5v for a 2k Ohm load. He'd need an absolute minimum Vcc of 6.5v.

 

hey thanx a lot guys..i cant believe i missed out such a simple concept of summer.
thanx again..
yes i had some doubt about using lm741(went ahead as v had worked wit tis IC in all the labs)..
i'll chk out on lm324.

 

actually i cant use supply voltage greater than +5V. We take power from USB port of the PC. so max allowed is +5V. that is why we thought of using the op amp in single rail mode.

 

Hello,

Take a look at this PDF from TI : http://focus.ti.com/lit/an/slod006b/slod006b.pdf
On page 16.54 thers is a selection table for 5 Volts opamps.
Chapter 4 goes about single supply usage.

Greetings,
Bertus

 

actually i cant use supply voltage greater than +5V. We take power from USB port of the PC. so max allowed is +5V. that is why we thought of using the op amp in single rail mode.

Take a look at ICL7660 and MAX1044 IC's; they are CMOS switched-capacitor voltage converters. They can give you a low-current dual +5v/-5v or +10v supply from a 5v source.

http://pdfserv.maxim-ic.com/en/ds/ICL7660-MAX1044.pdf