Temperature and humidity measurement meter

摘要

PURPOSE:To obtain an inexpensive small-sized temp./humidity measuring device having long switch life, by connecting a polarity reversal circuit, which is connected to the input terminal of an impulse oscillation circuit, to the control terminals of analogue switches for temp. and humidity. CONSTITUTION:When control signals different in polarity being the output signal and input signal of a polarity reversal circuit 17 are applied to the control terminals of a temp. analogue switch 13 and a humidity analogue switch 14, toggle operation for turning the temp. analogue switch 13 On and turning the humidity analogue switch OFF is performed. The impulse signal from an impulse oscillation circuit 18 can be applied to the control terminals of the temp. and humidity analogue switches 13, 14 by changing over the switch connected to the impulse oscillation circuit 18. Therefore, signals different in polarity are applied to the temp. analogue switch 13 and the humidity analogue switch 14 and temp. and humidity can be automatically subjected to change-over display.