| 摘要 |
PURPOSE:To detect the capacity of liquid with a simple constitution by originating a sound wave to the surface of the liquid and counting the time until the wave is reflected and returns, and detecting the rest of the liquid based on the time. CONSTITUTION:A pulse generator 13 is put in operation and a vibrator 11 for transmission is driven with its pulse through a driving circuit 14 to send the ultrasonic wave to the surface of the liquid. An FF circuit 18 is set through the operation of the pulse generator 13 to turn on a gate circuit 21, so a counter 22 starts counting a clock from a clock signal generator 19. When the sent ultrasonic wave is reflected by the surface of the liquid and received by a vibrator 12 for reception, a gate circuit 16 is turned on and the FF circuit 18 is reset, so the gate circuit 21 is turned off to stop the counting operation of the counter 22. An arithmetic circuit 24 calculates the rest of the liquid according to the counted value of the counter 22 and displays it on a display device 25. |
