i wanna do a simple temperature sensor mini project. my components including 22k and 10k resistors, 741op-amp and lm35dz temp sensor. i'm using national instrument labview 7.0 software to measure the signal output . but i'm getting the signal output with noise. Now i trying to reduce the noise but i don't know how to design a basic filter. i also don't know how to calculate the value of the capasistor. hopefully someone can tell me abt the calculation and the drawing circuit........

 

Are you sure the noise isn't on the power supply you're using? The LM35 has a relatively low impedance output, so it's not likely to pick up noise. 741's are really poor op amps, but not prone to be noisy without a reason. I would want to see what was causing the noise before trying to filter it out.

Can you post up a schematic of your circuit? That would help.