| 摘要 |
PURPOSE:To eliminate a voltage drop and noise and to protect a semiconductor pressure sensor from seawater, etc., by providing the semiconductor pressure sensor, a ship speed arithmetic means, and a display part such as a liquid crystal display part in the same housing. CONSTITUTION:A glass plate 14 for protection is fitted in the front surface of a front case 10 and a print panel 15, the liquid crystal display plate 16, a light guide plate 17 for illumination, and a reflecting plate 18 are fitted behind the glass plate 14. The semiconductor pressure sensor 21 as a speed detecting means is fitted to a rear case 11. Then the difference between pressure applied to a measurement pressure application part 22 and the atmospheric pressure strains the diaphragm of the pressure sensor 21 to cause variation in diffusion resistance value. The output voltage of the sensor 21 is supplied to a control circuit part 23 through a lead line. A circuit part 23 functions as a ship speed arithmetic means and processes the output voltage of the sensor 21 as prescribed to calculate a ship speed. Consequently, the signal line between the sensor 21, and speed arithmetic means and display part may be short, and the housing cuts off entering seawater, etc.
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