| 摘要 |
PURPOSE:To improve the preciseness of the titled electronic machinery, by reading a direction from the change in the display state of a magnetic display part in a display apparatus generated when electronic machinery is rotated in a globe magnetic field. CONSTITUTION:A magnetic detection circuit consists of a hole element 1 and an operation amplifier 2 while a conversion circuit consists of a ring oscillator 3, a gate 4 and a counter 5 and a display means consists of a decoder 6, a driver 7 and a liquid crystal display element 8. Hole voltage corresponding to the intensity of the magnetic field obtained from the hole element 1 is subjected to voltage amplification by the operation amplifier 2 and the output thereof is used as the drive power source of the ring oscillator 3. The oscillation frequency of the ring oscillator 3 has voltage dependence and is changed in proportion to drive voltage. The counter 5 counts the oscillation frequency of the ring oscillator 3 while reads the same from the gate 4 by a reading signal GS. As a result, the size of an external magnetic field caught by the hole element 1 is subjected to A/D conversion by the counter 5 to be converted to a pulse number and the pulse signal inputted to the counter 5 is displayed by the liquid crystal display el ement 8. |
