| 摘要 |
PURPOSE:To make it possible to measure and record the time length of the noise exposure which is received by a person in a workship and the like, by outputting a constant current when the microphone current exceeds a preset lower limit level, and displaying the current conducting time. CONSTITUTION:The current output of the microphone 1, which is proportional to the sound pressure, is rectified 2 after amplification 5 and inputted to a current conduction time meter 4 through a variable resistor 11 for adjusting the lower limit presetting level for the input voice pressure, a fixed resistor 11A, and a constant current passing circuit 11B. Then the current conducting time length is displayed. |
