[Amps] 60 Hz B+ Ripple

[Jim Brown]

On 12/31/2023 12:52 PM, Wayne, W0ZW wrote:
> As many have suggested, my test set-up was suspect due to a possible
> ground loop.  I repeated the test with a 3-prong to 2-prong adapter on
> the scope power plug to make its chassis floating.  Interestingly, the
> 60 Hz ripple was still present on the measured signal!

Wayne,

Removing the grounding pin is both dangerous and illegal. There is no 
such thing as a "ground loop" -- both by LAW and good engineering 
practice, all grounds MUST be bonded together. Problems blamed on 
so-called ground loops are actually the result of failure to do proper 
bonding.

Study N0AX's ARRL book on the topic, to which I contributed, W6RMK's 
chapter in the ARRL Handbook, which he contributed around 2011, and/or 
the slide deck for tutorial talks I've done at Visalia, Pacificon, and 
to several clubs.

http://k9yc.com/GroundingAndAudio.pdf

A common cause of hum and buzz in systems is getting mains power from 
outlets on different branch circuits. The cure is simple -- bond the 
green wires (or steel backboxes) together in the shack. There must also 
be a common point AT THE OPERATING DESK of every chassis that is part of 
the station, including computers if they're connected to station 
equipment. My slide deck shows how to do this for most computers, 
including laptops.

73, Jim K9YC