problem with opamp supply voltages

[grandhikiran2002]

while using an opamp I got this problem.when one of the opamp supplies is not there then o/p is going to saturation. ie, when -15 V is not given o/p is +14 V and when +15 V is not given o/p is -14 V .
Above is the case independent of feedback configuration and also independent of inv and non-inv input voltages.
Pls explain me why this is happening.

 

[FvM]

then o/p is going to saturation

What do you expect instead? If you connect only one supply terminal, is it surprizing to a get an output voltage near to this supply voltage?
To tell details, one must know the OP type, the complete external circuit, and if you're observing a real device or just simulating it?

 

[alexan_e]

Some opamps can work using positive supply (for example LM358 Single supply: 3V to 32V or dual supplies: ±1.5V to ±16V) but other opamps can only work properly with a positive and negative supply or you get a dc in the output.
You should read the datasheet of your opamp.

Alex

 

[FvM]

Actually, it's unclear what "one of the opamp supplies is not there" means exactly. If one supply is connected to ground, then the saturation state is surely not "independent of inv and non-inv input voltages". The OP will work, if the required common mode voltage is achieved.

 

[grandhikiran2002]

Thank you.one of the supply pin(+Vcc pin of opa 404) is left open with out even grounding it.