Could anyone tell me if an op-amp draws current when there is no input or output? Do the batteries need to be disconected when not in use? Many thanks.

 

Yes, they do - the quiescent current for each device is on its data sheet. Disconnecting the battery is the only way to achieve zero current draw.

 

Thanks beenthere, I did look at the data sheet but couldn't find it. What a brill site this is.

 

Thanks beenthere, I did look at the data sheet but couldn't find it. What a brill site this is.

In the TL072 datasheet, it is called Icc.

 

Very good Ron, that's 2% of the data sheet I can understand!!!

 

The datasheet tells you what is Icc:
Supply Current (each amplifier) 1.4mA typical and 2.5mA max.
If the opamp is doing any work then add the working current.