[RFI] Common Mode Line Filter

[Jim Brown]

On 8/10/2014 10:03 PM, David Cole wrote:
> Which forces me to ask...  What does the power company call common mode?

The voltage between neutral and green.

Thanks to a "Pin One-Like Problem" in most equipment, common mode often 
trash leaves equipment on the green wire, which radiates it. The Green 
wire SHOULD be bonded to the chassis at the point of entry, but it often 
is not. Instead, it goes to the circuit board, and may eventually find 
the chassis. Sometimes it fails to hit the chassis because paint is in 
the way. This is "The Pin One Problem."

In virtually all commercial line filters, the green wire bypasses the 
filter, so the filter does nothing to kill common mode current.

73, Jim K9YC