Grounding systems II

Ground Loop

In = Induced noise current Vn = noise voltage

Vn = In * Rs

• Definition : A ground circuit allowing ground currents to flow in a loop causing two problems.

• When noise voltage is induced due to magnetic coupling, the resulting induced current causes voltages in the signal.

• The return current may take a path further away from the signal current and create a radiating loop.

• Solution : Use a shielded cable and do not use the shield as a return conductor. (i. e. use either a twisted shielded pair or a tri axial cable.)