[Amps] Re Direct rectification of AC mains to derive the amp, VDD, supply

Jim Brown jim at audiosystemsgroup.com
Fri Sep 20 22:14:50 EDT 2013


On 9/20/2013 9:19 AM, peter chadwick wrote:
> I can still see the neutral float about 1 to 2 volts above ground on occasion such as when using, washing machine, tumble drier, both ovens and three cooker rings simultaneously.

The 1-2 volts is the result of Ohm's law, not the short earth rod. Earth 
is very lossy, so it's a high resistance path. To convince yourself of 
this, drive a couple of rods ten feet apart and measure the resistance 
between them.

By law, load current must flow in the neutral, not on the ground. The 
1-2 volts difference between neutral and ground is the IR drop due to 
that load current.

73, Jim K9YC


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