FATIGUE TESTING MACHINE

摘要

PURPOSE:To apply all the time the amplitude of a fixed value to a test chip by reading out the amplitude change of the test chip by a photodetecting element group and operating and correcting an output signal value in a vibration fatigue testing machine having an oscillator and a vibrator applying its vibration to the test chip. CONSTITUTION:Current generated in an ultrasonic wave oscillator 12 is loaded to an ultrasonic wave vibrator 4 through an amplifier circuit 17, a power driving circuit 20 and a waveform shaping circuit 23 to induce vertical vibration due to the ultrasonic waves in the test piece 3. A light emitting element 1 and a photodetecting element 2 are formed so as to sandwich the test piece 3. Since an output signal value of the photodetecting element 2 is reduced at the vibration of the test piece 3, a real amplitude value B of the test chip 3 is detected from the difference between said output signal value and an output signal value of the photodetecting element 2 at the zero amplitude. An amplitude comparator 8 compares the value B with a set amplitude value A and inputs its output to a phase correcting circuit 13 by adding a phase advancing signal 14 or a phase delaying signal 15 to the output in accordance with the size of the compared result or without adding any signal to correct the amplitude of the test piece 3.