a trip unit having a current leading element , an anchor having an up and a down position , and an oscillator having a first position and a second position . the oscillator in the first position permits the anchor to move into the down position , and the oscillator in the second position blocks the anchor from moving into the down position . additionally , a magnetic yoke surrounds the current leading element and the anchor . a magnetic flux flowing through the magnetic yoke moves the anchor into the down position . a magnetic yoke surrounding the current leading element and the oscillator provides a magnetic flux flowing through the magnetic yoke moves the oscillator into the first position , or into the second position .