Op amp issues

[duck_arse]

input to any voltage within the spec sheet spec. hence, not ground [unless dual supplies], not V+ [usually - both these nots are easy to remember, hard to get wrong].

[ElectricDruid]

Ah... so input to bias voltage on an unused op amp?

On a single supply, definitely yes. On a dual supply you'd use ground, but on a dual supply ground would be in the middle like our bias is here. Like Duck says, you *could* use any legal input, but it's not worth doing something special just for that so we re-use bias/ground.

OP - ignore this! Sorry for the hijack.

[antonis]

Shouldn't we wait for OP to define the use of single or dual op-amp..??

[ElectricDruid]

Shouldn't we wait for OP to define the use of single or dual op-amp..??

We're just chatting amongst ourselves while we wait for them to come back with a schematic, Antonis...