[Help] Basic Filter....

Thread Starter


Joined Sep 25, 2007
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........:p


Joined Apr 20, 2004
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.