Full­wave cir­cuit con­nect­ed with red L.E.D for­ward bi­ased (to grid sup­ply), with the an­ode con­nect­ed to the M.E.N stake and the cath­ode con­nect­ed to a sec­ond dis­tant earth stake.
Dur­ing low pow­er leak­ages (from the grid/M.E.N stake) it can be no­ticed that on­ly one L.E.D has enough en­er­gy to light.