opamp output gets stuck to 4.23 v .....not reaching 5V.........

[jit_singh_tara]

Dear friends ,

Facing a problem that :

I am converting pt100 resistance to voltage ......using non inverting opamp amplifier configuration, using +- 5V supplies .
But the opamp o/p voltage is not reaching full 5V.....

as i increase the feed back resistor rf to increase the gain.....there comes a stage when voltage on multimeter shows 5.23 v for a fraction of sec...then the the voltage gets stuck to 4.23 volts......

please suggest what to do........

 

[barry]

Tell us what opamp you are using. Not all opamps go all the way to the rail. Try reading the data sheet (Vout)

 

[jit_singh_tara]

i am using op07

 

[barry]

Did you read the data sheet?

 

[jit_singh_tara]

yes it said o/p swing +-12 V......

 

[crutschow]

yes it said o/p swing +-12 V......

But note that's with a ±15V supply. So that op amp output does not go to the rail. You need a rail-rail type op amp.

 

[jit_singh_tara]

i connected opamp supply to +-9 V it worked now.............thx friends......