thermocouple to 741 opamp

[smitgovani]

in proteus if connect ground then ans gettin right but connect to -9V (-Vcc) ans getting wrong....
thats main thing

 

[hardik.patel]

hi krp, i had seen your at below link, does it work with thermocouple??
https://tinypic.com/view.php?pic=2eq6yqa&s=5#.UtDlx_RDs1w

 

[ALERTLINKS]

I had a laminator. Its motor got burned. When I opend it. I observed the temperature controller in it. A 741 IC and thermocouple was used. It had a temperature setting knob on front. I can say, 741 can work satisfactorily with thermocouple.

 

[FvM]

741 can work satisfactorily with thermocouple.

Maximum 741 offset voltage is in a range of 100 °C temperature error. A 741 TC amplifier will at least need offset adjustment. Due to the offset drift, it won't be suitable for accurate temperature measurements. So "satisfactorily" depends.

 

[ALERTLINKS]

"satisfactorily" depends.

As cold junction compensation is not use in the application under discussion, an error of 30C-40 C should be expected under different atmospheric conditions. I once made a digital thermometer and control for a four stage compressor. Requirement was to be accurate within 5 degree C from 0-700C. It used TL07 front end and
lm35 for cold junction compensation. it was accurate within 2C.