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correct shield grounding? - RF Cafe Forums
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| Lostcause
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Post subject: correct shield grounding?
Posted: Thu Sep 29, 2005 5:14 am
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Joined: Thu Sep 29, 2005
4:56 am
Posts: 3
Location: North West UK
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Hello Gentlemen (& Ladies of course).
Newbie
to the world of RF and need any pointers you can
give.
I am building an amp and have introduced
shielded wire for the input and power cables and
wondered how or even if I should ground the shield
to anything?
The case is aluminium and earthed
to the mains. The input and grounding wires are,
again, shielded up to their connection to the PCB
and the potentiometer. I have made seperate compartments
for the transformer and regulation circuits.
Should I leave the shielding or ground it to the
case or, or, or?
Any help would be much appreciated.
Thanks
Lee
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IR |
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Post subject:
Posted: Thu Sep 29, 2005 8:09 am
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| Site Admin |
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Joined: Mon Jun 27, 2005
2:02 pm
Posts: 413
Location: Germany
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Hello Lee,
You should apply your voltage
supply to the amplifier through
Feedthrough
connector. This connector is a LPF that filters
out any noises that are present in the supply rails.
The connector is screwed to the case, and should
be located close to the output of the amplifier
in order not to add noise to the sensitive input.
The shielding of the wires should be connected
to the aluminium case. You should form a perfect
(As much as possible) ground plane from the input
of the amplifier to its output. The GND of the supply
voltage should be in the same potential to this
ground plane, therefore you should connect it too
to this ground plane. It is a good idea to make
different compartments for the regulator, amplifier
and transformer and by that to decrease potential
coupling between these elements.
I hope
this helps.
_________________
Best regards,
-
IR
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Guest |
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Post subject:
Posted: Thu Sep 29, 2005 8:18 am
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Thanks IR, good feedback!
Should I look out for
grounding 'loops' and only ground them at one end?
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IR |
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Post subject:
Posted: Thu Sep 29, 2005 8:29 am
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| Site Admin |
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Joined: Mon Jun 27, 2005
2:02 pm
Posts: 413
Location: Germany
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You welcome!
Grounding loops usually appear
in system with more than one ground e.g. in Mixed-Signal
systems. If I understood your circuit, you use only
an RF amplifier; therefore, you should connect all
grounds point to the same ground plane and these
points will be in the same potential, so essentially
there is only one ground.
_________________
Best regards,
-
IR
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Posted 11/12/2012
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