| 摘要 |
PURPOSE:To observe and monitor the properties of temp. change as an alarm for a thermal failure, by making a short-circuit of electric charge generated by the temp. change by disposing an electrode at the opposite surface of a piezoelectric material of a plain plate and by detecting the amount of temp. change by obtaining ultrasonic pulses in accordance with the amount of temp. change. CONSTITUTION:Electric charge is accumulated is a capacitor C1 or C2 through a diode D1 or D2 in accordance with the polarity of electric charge generated in a piezoelectric ceramic TD, and the accumulated charge is discharged in a monent by a switch S1 or S2. The amount of change of the temperature given to the TD is recognized by detecting ultrasonic pulses at the time of discharge by a piezoelectric element etc. through an acoustic medium and converting to an electrical signal and appreciating this. |
