# Output voltage of op-amp in open loop configuration

What is the output voltage of op amp in open loop configuration when voltage in inverting input is greater than the one in the non-inverting input?

Is there a technical term for this output voltage?

Do datasheets refer to it?

• Well, the output will be either the high rail voltage or the low rail voltage because that's what open loop op amps do. Suppose you ground the inverting input for a moment and the non inverting one is positive. Now what happens? Then flip it and what happens? Nov 16, 2018 at 19:01

What is the output voltage of op amp in open loop configuration when voltage in inverting input is greater than the one in the non-inverting input?

The output will swing as far negative as it can go.

Is there a technical term for this output voltage?

Saturation voltage.

Do datasheets refer to it?

Yes. Maximum and minimum output voltage. With common op-amps this is 1 to 3 V from the supply rail. For "rail-to-rail" op-amps it can be close to zero at low currents.

• And if there is a single positive power supply and the input differential signal Vin+ - Vin- is smaller than 0, is it possible to predict the output voltage? I have just set up a light sensor with an LDR and a LM358 op amp acting as a comparator. I think the circuit I made in the breadboard is successful but when fiddling with a potentiometer, I noticed that a small differential differential input of -0.23V sometimes causes the output to go high and sometimes to go low. I want to be able to mathematically simulate the circuit behaviour for an open educational resource. Any ideas? Nov 17, 2018 at 15:37
• I think you need to ask another question. Include a schematic. If this question has not been answered satisfactorily then perhaps an edit is required. Nov 17, 2018 at 15:43