Page 1 of 1

DSO138 showing 50 Hz signal even witout connections

PostPosted: Fri Nov 15, 2019 2:18 pm
by luto65
Dear All,
my DSO138 is powered by a 9V transformer that stabilise 50Hz the 220 AC current and delivers 9V DC.
When I connect the provided probe to the DSO138, then I can observe a clear 50Hz signal in the display even without attaching the probe to anything.
Is this "normal" ?