| 摘要 |
PURPOSE:To count number of passers or frequency of passage by providing a counting circuit which counts and displays the passing frequency of bodies at prescribed intervals of time and also the sum of passing frequencies in a day, for example. CONSTITUTION:When modulated light 4 emitted from light emitting element 3 is shut out by man 30, modulated light 4 arriving at photodetector 6 decreases suddenly and this decrease in photodetection quantity is detected by level detecting circuit 10, whose output signal is sent to output circuit 11. The signal of output circuit 11 is led to counting circuit 16, which counts the frequency in output and the count result is displayed on display part 17. With output (alpha) of frequency dividing circuit 23 of control part 21, the storage and display of counting circuit 16 and display part 17 are reset. Next, operating access circuit 27 with such button 30 makes it possible to display the memory value of memory circuit 19 on display part 28. This constitution makes the detector count the number of passers, frequency of passage, etc. |
