| 摘要 |
PURPOSE:To enable detection of gas concentration by detecting the frequency difference between a standard crystal vibrator as a watch standard vibration source and gas detecting crystal vibrator. CONSTITUTION:A standard crystal vibrator 1 is shielded from the external atmosphere. When gas is adhered to the surface of a detecting crystal vibrator 8, its vibrating frequency is altered. The output of a standard oscillator circuit 2 is divided in frequency by frequency dividers 3, 4, counted by a counter 5 and displayed on a display unit 7. The output of a gas detecting oscillator 9 is, on the other hand, divided in frequency by a frequency divider 10. The frequency differences of the outputs of the divider 10 from the standard frequency are produced by comparators 11, 12, and counted by a counter 13 at every one minute by one-period timing pulses P1, which are compared with the value 15 of the counter 13 at one minute before by a comparator 16 to generate an alarm by an alarm unit 17 when the difference is higher than predetermined value. |
