A new non-contact digital speed sensor is presented using soft iron an
d Metglas 2605SC amorphous ribbon. This sensor uses the change in the
magnetic flux produced when a rotational iron bar comes between a perm
anent magnet and the gap of the soft iron or amorphous core. The ampli
tude and frequency of the signal are directly proportional to the spee
d of the iron bar. The soft iron speed sensor has been found to be fav
orable compared to the amorphous sensor. It has the advantages of line
arity, accuracy and wide range.