| 摘要 |
<p>PURPOSE:To detect the abnormal state for recording and reproducing by providing a discharging circuit which controls the base potential of a PNP type transistor (TR) and a circuit which outputs an abnormality occurrence signal on a basis of presence/absence of the current supplied from the collector terminal of the PNP type TR. CONSTITUTION:If a current does not flow to a coil 17al because of, for example, disconnection of the coil 17al and information is not normally recorded during the recording operation, a self-induced electromotive force is not generated in the coil 17al and the electric charge stored in a capacitor 9a is discharged continuously through a constant current source 11a. Consequently, the base potential of a PNP type TR 9a is reduced and the PNP type TR 9a is made conductive, and a current is supplied to an amplifying part 3 from a voltage source VDD through the PNP type TR 9a, and the abnormality occurrence signal is supplied to a control circuit which controls recording information to report the occurrence of abnormality. Thus, the abnormality is detected surely even during the information recording operation.</p> |
