# Sensitivity expression

Andy_ToK
Hi,
I have a question about the sensitivity of measurements in experiments.
e.g. We measure the current of a circuit and it's 1A. if the sensitivity is 1 part in 100, does that mean we can't distinguish the current between 1-1/100A and 1+1/100A?

Thanks

Andy_ToK
Thanks, that's what i meant

Cyrus
Whoops I just told you the wrong thing. I just told you about resolution.

Sensitivity is the change in output/ the change in input.

So if you have a change of 1V in your circuit, the instrument will show a change in 1/100 V.

Andy_ToK
ya, so it can't tell when the change is smaller than 1/100V, right?

Cyrus
No, that's not what sensitivity is. Its the ratio of the change in input to the change in output. Thats totally different from what I told you at first, the resolution.

Andy_ToK
Sorry, but I'm confused now.
Let's just stick to the example i mentioned. the initial current is 1A and the sensitivity of the ammeter is 1 part in 100. And if the current changed from 1A to (1+1/1000)A, what value will be displayed on the ammeter?

Andy_ToK
anyone？
Thanks