| 摘要 |
PURPOSE:To make free the range of alarm setting and at the same time unnecessiate an alarm display element by comparing the input through a phase conversion circuit with a limit setting voltage and controlling the saw-toothed wave generating circuit. CONSTITUTION:By logical product of a rectangular wave oscillating circuit 8 and the reset output of a reset terminal 9 a phase inversion circuit 13 is controlled. When the input voltage from the terminal 1 is high, the node 2 is always at a low level and the output of a time constant circuit 14 for generating saw tooth form wave through a comparator 4 for which the limit voltage is set becomes a low level. When the input voltage falls, and the reset signal from the terminal 9 is of high level, the output of the circuit 14 rises according to the time constant. It is the same with a node 3 and a time constant circuit 14' and LED1, LED2... are all turned out and then lighted successively or all lighted and then turned off successively according to an input voltage that is over or below a specified value, and the alarm display is displayed by using LED1 that are lighted according to a low level input voltage of the reset output without using a specialized element. Further, the range of alarm can be freely set by changing the limit voltage of the comparator. |
