CT accuracy class 5P10 current transformers micro amp current transformer current sensor on PCB micro amp current transformer current transformers micro amp current transformer micro amp current transformer hall effect ct micro amp current transformer hall effect ct sensitive current transformer current transformers current transformers CIS current transformer current sensor on PCB CT accuracy class 5P10 current transformers sensitive current transformer micro amp current transformer micro amp current transformer CIS current transformer detect low levels of earth-leakage current current transformers medium voltage current sensor medium voltage current sensor current transformers sensitive current transformer hall effect ct micro amp current transformer