Summing op amp is negative op, how to convert to positive?

[Tiger555]

Hi, I need to take summing up O/P from an op amp, but i am getting in -ve, how to make it +ve voltage?

Thanks.

 

[Nigel Goodwin]

Add another opamp as an inverter after it.

 

[Tiger555]

Hi,

I when i tried that, i got +15v as output. not the exact +ve. that is , if the input -5v and i need output +5v ?? Plz see the link below..

Circuit Simulator Applet

(cut n paste)

Add another opamp as an inverter after it.

 

[Nigel Goodwin]

Hi,

I when i tried that, i got +15v as output. not the exact +ve. that is , if the input -5v and i need output +5v ?? Plz see the link below..

Circuit Simulator Applet

(cut n paste)

You're missing the input resistor, equal resistors, gain of -1.

 

[Tiger555]

Thanks alot! Got the idea to solve it. Cheers!!

You're missing the input resistor, equal resistors, gain of -1.