Op Amp Question. Can this be done?

[godfreyl]

Does this mean i can use all Dual Supply op-amps with single supply also,as long as i do not exceed maximum range

Short answer: Yes.

Say, i have AD 8672 op-amp.It was given in it's datasheet that it needs Dual Supply Operation:±5 V to ±15 V.So can i use AD 8672 with supply rails V+ at 10 V & V- at 0 V.

Yes.

You can also use any "single supply" opamp with a dual supply.

 

[rahdirs]

@godfreyl:Thankyou ,so for LM741A op-amp the absolute maximum ratings of supply voltage is given in data-sheet as ±22V.So i can apply +22V at V+ pin & -22V at V- pin.
If i use it in single supply can i apply +44 at V+ pin& GND at -pin or is the maximum +22V at +pin & GND at -pin.

 

[godfreyl]

Yes. you can put +44V on the V+ pin and GND on the V- pin.
You can also put GND on the V+ pin and -44V on the V- pin.

The opamp only cares about the voltage between it's pins. You can put +240V on the V+ pin and +200V on the V- pin if you want to. Lots of circuits (e.g. portable radios) don't have ground connected anywhere.

 

[rahdirs]

Yes. you can put +44V on the V+ pin and GND on the V- pin.

@godfreyl: Then why isn't this simple adder circuit not working.I just wanted to see if it works,i am tried using 44 V on V+ pin & 12 V on V- pin.

 

[FvM]

Then why isn't this simple adder circuit not working.I just wanted to see if it works,i am tried using 44 V on V+ pin & 12 V on V- pin.

Because the 741 common mode range is exceeded, see e.g. posts #16, #18 and #20.

Keeping the maximum ratings is necessary to avoid damage of the chip. But you must also take care of the other electrical characteristics, e.g. input/common mode voltage range to make it work as an amplifier. In this case, both OP inputs must have a voltage 3V above V- (typically 2V). But you are connecting In+ to a voltage 12V below V-, violating common mode range and maximum ratings.

P.S.: You should also check if the expected output voltage of the adder can be ever achieved. In the present circuit it's -30V. Besides missing supply voltage headroom, the ouput won't drive 30 mA.

- - - Updated - - -

The circuit is working correctly, OP in- and outputs have all the same voltage of +20V against ground.

The last update was referring to a post that has been deleted in the meantime. I guess, you have found the fault yourself.