Re: Analog signal conditioning

> Here is the problem: I need to measure a remote resistance
> of 0 to 500 ohms with the AD input on a Pic 16F877A. what
> ever I do, it has a lot of jitter on the reading. A super
> cheap Harbor Freight Ohmmeter works fine.



Look at the signal at the measurement point with an
oscilloscope.
It may have mains hum on it and the cheap DMM will be a dual
slope (long  integral) with mains frequency rejection (slope
length timed for mains cycle rejection or multiple cycles).
If mains hum is an issue then heavy filtering may assist.


        Russell


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