One more newbie opamp question(really easy answer)

[rockgardenlove]

So I have this shematic:


And an opamp with this pinout:


What goes to what?  I was assuming the + on the diagram went to the V+ on the opamp...and that - on the diagram went to v- on the opamp...is this right?

And I don't have a 4.5 volt power supply...whats the 4.5 volt stuff about?


Thanks, sorry for my idiocy

[burnt fingers]

There's a lot of good reading on this stuff.  Dig a little and you shall find. 

[rockgardenlove]

I was kind of hopeful that I would get a response

I've searched the forums...couldn't find it.  The problem is that so many thread and pages on the net contain the keywords opamp, pinout, etc...

[rockgardenlove]

So it works when you put -9v into the inverting input, but not when you put it into the - pin...?  I'm confused...?  Something I'm missing?  At least it lets the signal through when you put the negative battery lead to the inverting input.

I got the info from the FAQ...smart me

[pyrop]

This should help you mate.


Well the 4.5v is refered to as voltage reference which is half voltage.
To get this from 9v you need a voltage divider. Search for voltage divider^ and you will find.

pyrop

[rockgardenlove]

I read a Keen explanation of the voltage divider, and it made sense...I just didn't understand how to calculate what values you need...?

[JimRayden]

V(+) and V(-) are the supply voltage.
"Output" is the tip of the triangle.
Non-Inverting input is the "+" input of opamp (the one with 1M resistor to 4.5V)
Inverting input is the "-" input of opamp.

Other pins are left unused.

Hmm, 4.5V... How about this:

http://www.runoffgroove.com/bb-pwr.html

----------
Jimbo

[rockgardenlove]

Great link, thanks!

[trevize]

you should go on texas instruments webpage and look for their pdf. in the amplifier section you'll find the single supply pdf.

when you see 4.5v it's a virtual ground (you create a virtual ground with a voltage divider so intead of having v+, gnd and v- you have v+, v1/2 and gnd).