On Sat, Apr 5, 2025 at 05:21 AM, Jay Czaja wrote:
I have a question. What is the best way to measure ripple on the LV supply.
When I checked it the first time, I had the 2247A on an isolation transformer
with my 2245A connected directly to mains AC. I used a x1 probe on my 2245A to
check for ripple and clipped the ground lead of the probe to the chassis of
the 2247A.
No need to use an isolation transformer to float the scope for this measurement. The chassis of the scope is grounded normally, not like old CRT TVs or monitors that mostly had a "hot" chassis.
Just use your other scope, set it to AC coupling and go as low in attenuation to get a readable signal across the power rail being tested. Connect the probe to ground and the tip to the power rail and see how much noise level you measure. You might also want to switch in the 20MHz bandwidth limiter so as to possibly get a more cleaner and relevant display. Ideally use a X10 probe, but X1 should be ok.
