A writing device includes a writing pen and a light emitting diode display panel. A pattern generator circuit 10 stores and provides data patterns and respective position control data. The sensor circuit is also capable of temperature compensation because temperature changes of a reference voltage and a reference voltage match a temperature change of an output signal of an amplifier circuit which is caused by a temperature change of an output signal of a Hall element. The external tuner outputs the TV broadcast program which is scheduled to be recorded to the line input of the recorder, on the basis of the registered command. Then said shroud is withdrawn up to disengaging said hook from said housing. Thus, by turning off packages of the power MOSFETs disposed on an outer side of the main circuit loop and turning on packages of the power MOSFETs disposed on an inner side of the loop, the parasitic inductance of a main circuit is reduced, so that the switching loss can be reduced and efficiency in a light load can be improved.