Demagnetizing power source

Claim 1

A demagnetizing power source for supplying direct current from a rectifying circuit to a exciting coil which current has its polarity changed over alternatively by a polarity changing-over circuit and its change-over cycle gradually decreased to produce an attenuation alternating field for demagnetization in said exciting coil, comprising a memory circuit for storing a plurality of demagnetization patterns and sending actuating signals to said polarity changing-over circuit, an address setting circuit for sending address assigning signals assigned by a initial address selecting means for selecting said demagnetization pattern according to demagnetization starting signals to said memory circuit, a clock pulse generating circuit, a counter circuit for receiving clock pulses from said clock pulse generating circuit and time assigning signals from said memory circuit assigned by address assigning signals of said address setting circuit to produce ripple carry when the number of said clock pulses reach a predetermined value specified by the time assigning signal and an address changing signal generating circuit for receiving said ripple carry and sending the address changing signals respectively to said address setting circuit and said counter circuit to advance the output address assigning signal sent from said address setting circuit t 0 said memory circuit towards sequentially succeeding address assigning signals according to the selected demagnetization pattern and apply the succeeding time assigning signals produced from said memory circuit to the input of said counter circuit, whereby the quiescent condition is set by quiescent signals sent from said memory circuit to said address setting circuit after performing one selected demagnetization pattern.