Farad22
Junior Member level 2
How does ground loop voltage changes with ground loop impedance
Hi,
I have a question about ground loops. One thing I don't understand is how an "isolation" resistor can eliminate ground loop problems. Take the following setup:
If a certain voltage (Vg) is induced in the ground loop (for example by 50Hz induction) then the loop current (Ig) is determined by induced voltage and the resistance of the loop, according to Ohm's law. Let's say this induced voltage is 1V. If we only have a ground loop wire impedance of 0.1 Ohm then the ground loop current is 10A. If we put in an isolation resistor (10 Ohms) then the current will be 1V/(10+0.1 Ohms) = 0.1A. So the current in the loop can be reduced, but the induced voltage is the same in both situations. If the ground loop noise voltage (Vg) stays the same then what difference does the isolation resistor makes?
Thanks
Hi,
I have a question about ground loops. One thing I don't understand is how an "isolation" resistor can eliminate ground loop problems. Take the following setup:
If a certain voltage (Vg) is induced in the ground loop (for example by 50Hz induction) then the loop current (Ig) is determined by induced voltage and the resistance of the loop, according to Ohm's law. Let's say this induced voltage is 1V. If we only have a ground loop wire impedance of 0.1 Ohm then the ground loop current is 10A. If we put in an isolation resistor (10 Ohms) then the current will be 1V/(10+0.1 Ohms) = 0.1A. So the current in the loop can be reduced, but the induced voltage is the same in both situations. If the ground loop noise voltage (Vg) stays the same then what difference does the isolation resistor makes?
Thanks