| 摘要 |
A method for generating an electrical signal and a sensor device (10) for executing the method. The signal is generated because of a change in a fluid-filled space. A sensor element (12) of the sensor device (10) detects the heat transfer over time between the sensor element (12) and the fluid. The sensor element (12), which has a temperature-dependent electrical conductivity and to which a voltage has been applied, is brought to a temperature which lies outside the range of the fluid temperatures. In the passive phase, the fluid is brought to a constant passive temperature by a heat transfer between the sensor element (12) and the surroundings. The sensor device (10) provides a constant passive output voltage. A heat transfer between the sensor element (12) and its surroundings takes place in the active phase by changes in the fluid-filled space. The sensor device (10) provides an active output voltage, which is different from the passive output voltage. When a difference between the output voltages is exceeded, the signal is generated. The device can be used for triggering the flushing action in sanitary installations, and for keeping a level constant, for example in aquarium installations.
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