Question about using an Op AMP??!11!!!

Angela1

Can someone please help me!!! This is like the last part of my project and I can't figure it out!!

I am trying to·put one of the I/O·pins' voltage into a·741 noninverting amplifier that multiples the voltage. I understand the configuration·BUT THE PROBLEM IS THE V-. I don't·know·how to get the negative voltage from a I/O pin or from anywhere else for that matter...·If I could figure out the V+ and V- aspect of the 741 Op Amp then I can finish my project. I don't know how to get the V- using the stamp configuration or what to do to get it... I don't know!!!

Any ideas how to·use the voltage·comming from·an I/O pin and putting it through some type of circuitry that makes the voltage about twice or three times or·maybe adding 5 volts to it?? This is the last part of my project so it is really getting to me!!!·Please HELP me·or I will cry... seriously...and i'll be out of your hair for good (probably)

Duffer

Give the following link a look: http://www.uoguelph.ca/~antoon/gadgets/741/741.html

BTW, this is the first hit on a Google search for "741 Op Amp"

Duffer

Phil Pilgrim (PhiPi)

Are you stuck with using the LM741? It's pretty much yesterday's news. Even the LM358 is more up to date. IYou might want to investigate either the MAX660 (5.5V max to -5.5V) or LM7660 (10V max to -10V) voltage converters. They will convert a postive supply voltage to negative. Neither will likely provide an adequae negative supply for the '741, though. Which brings me back to my original question.

-Phil

Angela1

Thanks Duffer for the reply. I did a google search first too!!!