| 摘要 |
PURPOSE:To easily detect the reverse insertion of a disk by detecting the index hole of a floppy disk by a reverse insertion detector provided symmetrically about a center line passing through the center of the floppy disk when the floppy disk is inserted into a device. CONSTITUTION:If the floppy disk is inserted with its index hole 5 in the opposite direction, this insertion is detected and a spindle motor is driven to rotate the disk 2. Then, when the hole 5 reaches the position where an LED 20 and a phototransistor TR 21 are provided, light emitted by the LED 20 is photodetected by the TR 21 through the hole 5. At this time, the TR 21 turns on to supply electric power to the TR 21 from a DC power source +VCC. Consequently, the input side of an inverter 22 falls to a low level, so a high potential is supplied to the base of an NPN type TR Q. Consequently, the TR Q turns on and a disk opposite-direction display indicator 33 illuminates to indicate the disk 2 is inserted reversely.
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