| 摘要 |
A 10 kHz multivibrator comprising two NOR gates , sets a monostable circuit whose capacitive element is the humidity sensor. The output pulse width is a function of the humidity. A linearisation circuit is coupled by a three-wire cable to an analyser with an A/D convertor driving a seven-segment display. - Above 50% humidity the signal is amplified by a differential amplifier, with comparators operating an LED when it is outside the 60-90% range. A one-minute delay circuit with two differentiating stages drives a Schmitt trigger . Another comparator supplies a synchronising circuit contg. two bistables , the latter acting as a memory for its output.
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