BACKUP TYPE ABSOLUTE VALUE ENCODER

PROBLEM TO BE SOLVED: To reduce the power consumption of a battery at the time of backup and to prevent the decline of noise resistance performance at the time of normal use. SOLUTION: This encoder is provided with a magnetoresistive element 2 for detecting a multi-rotation amount, a main power source for supplying a voltage to the magnetoresistive element 2 at the time of a normal operation and a backup power source 5 for supplying the voltage to the magnetoresistive element 2 at the time of a power failure. In this case, the voltage higher than the one of the backup power source 5 is supplied from the main power source 4 at the time of the normal operation. Thus, the power consumption of the battery at the time of the backup is reduced and the noise resistance performance at the time of the normal use is improved.