[Phil Allison]

"Ian Bell"

First it is not a ripple - it is not repetitive. Secondly, it is shortish
but sudden changes of a few mV so the scope does not really need a
response down to 1Hz. Lastly, the scope is a Rapid Electronics 7020A 20MHz
dual channel (which is a re-branded Pintek) and its -3dB point is quoted
as 20Hz.


** Very unusual for a scope to have that much roll off at 20 Hz, most are
3dB down at 3 to 6 Hz in "AC " mode.

In any case, leave the scope input set to " DC " and fit your own isolating
cap in series with the probe - a 0.1 uF, 400 volt film type will give
a -3dB point at 1.6 Hz, or 0.16 Hz if you use a 10:1 probe.




...... Phil