getting fluctuation in read analog input A)

Hi I am measuring air pressure from air pressure sensors. So, I am getting output from the air pressure sensors & then from the amplifier. but the output is fluctuating in terms of voltage. Can anyone help me to get prooper reading from Analog pin?

It may help if you can post details of your sensor and amplifier wiring. In the meantime perhaps you can check for electrical interference or maybe temperature sensitivity.