AVR-Chat

----- Original Message ----- 
From: Randy & Zonya Ledyard
To: AVR-Chat@yahoogroups.com
Sent: Monday, January 24, 2005 8:25 AM
Subject: RE: [AVR-Chat] OT - Grounding Question


James

I was referring to the "green" ground wire, not neutral - I'm planning on
using a 3-prong plug for the input - the hot and neutral run to the primary
on the transformer, but I'm confused about where the AC ground should go...

Should that AC ground be tied to the case and to the DC ground, or should
the DC ground be isolated from the AC ground?

Also, what about the shell of the transformer, should it be tied to AC
ground, DC ground, or both? This is for audio equipment (guitar effects) if
that makes any difference....

I would connect AC mains earth/ground to DC ground and ground the 
transformer shell. There should be a suitable fuse in the connection to the 
AC mains line (hot). Apart from safety considerations, this should minimise 
mains hum and RF pickup. Get a transformer with an earth/ground screen, if 
possible. All UK supply sockets have an earth connection, and use a 
three-pin fused plug. "Double-insulated" equipment doesn't use the earth 
connection, of course.

Leon 



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