TAPE TENSION ADJUSTING DEVICE

PROBLEM TO BE SOLVED: To increase the change frequency of braking force so as to make tape tension constant almost steplessly by computing on the basis of the length pulse data and outer diameter data of a linear body, and reducing voltage, applied to an electromagnetic brake, stepwise. SOLUTION: An arithmetic circuit 3 takes in a measuring pulse signal 1 related to the length of a linear body to be a tape winding object and a signal from an outer diameter setter 26 while calling data corresponding to the condition of the length and outer diameter of the linear body, previously stored in a data memory 6. Using this data, the arithmetic circuit 3 performs relative operation to obtain digital data. The digital data is converted into analog data by a D/A converter 4 and amplified by an amplifying circuit 8, and then fed to an electromagnetic brake 10 of a tape pad. Voltage applied to the electromagnetic brake 10 is thus reduced stepwise so as to control the tension of a tape to be constant. This brake 10 is of such an electromagnetic brake type that its braking force changes according to supplied input voltage.