| 摘要 |
A barometer of the evaporation or hypsometer type comprising an enclosed cylindrical bulb partially filled with a working fluid, a first temperature measuring device positioned in the bulb for measuring the temperature of the working fluid therein, a relatively thin extended tube connected to and extending upward from the bulb, a second temperature measuring device positioned on the tube at a position away from the bulb for measuring the temperature of the working fluid at that location, an electrical heater associated with the bulb for bringing the working fluid to the evaporation temperature, a mechanism for transmitting ambient pressure to the inside of the tube-bulb combination and preventing escape of working fluid connected to the upper end of the tube, electrical means connected to the heater for providing a heating current thereto, control means connected to the second temperature measuring device and the electrical means for controlling the level of heating current provided to the heater, and output means connected to the first temperature measuring device for providing an output voltage, said voltage being related to the ambient barometric pressure.
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