AVR-Chat

Randy,

That green wire is your ground.  All of your ground returns ought to be 
connected to it, as well as the transformer casing which would be 
automatic is you ground the case of your enclosure...assuming you're 
using a metal enclosure.

The white wire, neutral line, is also tied to ground (earth) but at 
either the breaker box or the transformer.  The green wire is always 
your earth ground, at least it's supposed to be.  Never connect your 
earth ground and neutral together at the equipment end of the power main.

You might also want to make sure you separate your analog circuit 
returns from your digital circuit returns (grounds) connecting them 
together only at one point on your circuit board.


REB



Randy & Zonya Ledyard wrote:

>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....
>
>Randy
>
>  
>
>>-----Original Message-----
>>From: James Washer [mailto:washer@trlp.com]
>>Sent: Monday, January 24, 2005 1:24 AM
>>To: AVR-Chat@yahoogroups.com
>>Subject: Re: [AVR-Chat] OT - Grounding Question
>>
>>
>>
>>I'm sure lots of folks will have lots to say about this... but
>>let me just ask a question of you first.
>>
>>When you say "ground from the 100 VAC" do you mean "ground" or
>>"neutral". i.e. Are you using a 3-pronged-ground-lug plug, or the
>>more conventional two-pronged plug, which has no ground, only hot
>>and neutral, and which may or may not be polarized(, and which,
>>even if polarized, may be plugged into an outlet with hot and
>>neutral reversed)
>>
>> - jim
>>
>>On Mon, 24 Jan 2005 00:55:45 -0500
>>"Randy & Zonya Ledyard" <rledyard@bigfoot.com> wrote:
>>
>>    
>>
>>>Basic question about grounding here, couldn't find the answer on several
>>>schematics I looked at, so I thought I'd ask it here, so the
>>>      
>>>
>>experts can set
>>    
>>
>>>me straight.
>>>
>>>I putting together a power supply for my son, to power several
>>>      
>>>
>>of his guitar
>>    
>>
>>>effects boxes, and I had a question about grounding.
>>>
>>>This is a basic transformer/diode bridge/7809 regulator with filter caps
>>>circuit, running off 120 VAC (US)
>>>
>>>Do I connect the ground from the 110 VAC to the ground on the
>>>      
>>>
>>DC side? If
>>    
>>
>>>it's in a metal case, should the case be grounded to the 110
>>>      
>>>
>>VAC side also?
>>    
>>
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