Need help underderstanding graph.

[thermal]

  New to using scopemeter. I made a measurement using the Fluke 124 connected to a 9 volt battery. I was expecting the graph line to be straight when connected but it looks looks a little jagged. Can anyone explain why ? Pictures of measurment attached.

[PA0PBZ]

If you digitize an analog value there will always be a rounding error, that is what you see on the display. And then there is noise, jitter, stability... What you see is perfectly normal.

[thermal]

 :-//Should I see the same jitter when the battery is not connected?

[PA0PBZ]

:-//Should I see the same jitter when the battery is not connected?

They probably have a circuit that detects when the input is zero and then suppress the jitter.
If you look at this official picture from Fluke:



you see the same wiggle...

[thermal]

  How do I determine if the jitter is caused from the scope operation or a problem with circuit being measured ?

[w2aew]

How do I determine if the jitter is caused from the scope operation or a problem with circuit being measured ?

One way that often works (but not always) is to change the vertical scale to a lower V/div setting. If the noise has the same variation in number of pixels, then it's probably the scope.  If the noise occupies more vertical pixels at lower V/div settings, then it's likely your circuit.

Averaging can be used to remove noise that is I correlated to the signal.

[Simon]

If the scope is unconnected then chances are you will pick up a 50Hz sine wave (or a variation depending on circumstances) that comes from the mains supply, 60Hz if your in the US