Offset nulling in OP07?

picstudent said:

Hello

Is it mandatory to use offset null-ing preset in OP07 instrumentation op amp?
OP07 has only very very low offset voltage. Can we null such very low values using 20K preset? If so can we use blue multi-turn trim-pots for the purpose? Or any special parts for that?

My OP07 is used to amplify a shunt resistor voltage drop in millivolts to around 2.048 Volts. It goes to a ADC. So gain and offset critical to keep voltage within scale of ADC. But since all resistor values are not available can we use trimpots in the feed back path to adjust gain and offset? Or else how the range is adjusted using available parts?

Please suggest

regards

Roy Thomas

Click to expand...

ericgibbs said:

hi Roy,
The OP07 datasheet states that the offset null is optional.

Its usual to trim the gain/offset with multiturn cermet pots.

Click to expand...

picstudent said:

Thanks.
cermet pots seems to be big and very costly.(I searched farnel- it is like big potentiometers, not usual PCB solderable trimmers. right?)

Thanks

or is this the thing you suggest
**broken link removed**

Roy

Click to expand...

ericgibbs said:

hi Roy,
The cermet multi are small screw driver adjust types.
This type.

BOURNS|3296W-001-502|TRIMMER, 25 TURN 5K | Farnell United Kingdom

Click to expand...