How to Measure Op-Amp Quiescent Current

Whatever you do, you need to do it to all four OPAMPs. My gut feeling with OPAMPs is that you don't want to ground both inputs. Because of the high gain even a tiny bit of noise can cause oscillation. What I do with my unused OPAMPS on a quad package is tie the output back to the (-) input, like a unity gain voltage follower and ground the (+) input. That may not be the best thing though if your OPAMP isn't stable at unity gain.

But my suggestion is to look through some OPAMP data sheets, especially for military grade parts. They usually show the test circuits that they use for various measurements.

What quescent current do you hope to test? sum or individual element?

Ordinary LM324 is one of quad package.for this ezample, what quality do you measure?

the covininet way is use a current probe witha digital oscillator.

you can read any current on screen. or refer to 1# to read manual.

or use a small resistor as a sample component to convert to voltage.

I suppose if you cannot lay your paws on a data sheet that shows you a various configurations and measuring details then your next best option is to setup the circuit you want in series with a low value pre-measured resistor (metal type preferred).

Then monitor the voltage across it with a sensitive enough digital-meter and by using ohms law and the measured (not rated) resistor value you can work out the current near enough.

Other than the aboves for better accuracy you need a good current meter that you may not even have as we're talking about more in the nano than micro amp range!

Thanx for your information about way to measure current.

one of the op-amp OP495, datasheet claims that power supply current is 150uA with Vout=2.5V, Vcm=2.5v, Vs(supply voltage)=5V and infinite load.

i want to test this claim practically.Now i have developed circuit in unity gain(i.e o/p connected to inv. terminal) with Vin as 2.5v and No load.this same configuration is put for other device in the package(Quad pack op-amp).

Now i am measuring the supply current by using DMM.

Hope i am right or is there any other way to evaluate quiescent current/supply current?

The method I gave you is simple and easy to follow and had been used in the labs even for donkey's years until precision meters came about.