| 摘要 |
<p>PURPOSE:To set a long-period timer and also to change set time range easily by providing a method of switching and setting a division ratio of a variable oscillation frequency through time-constant operation and a detachable scale plate for operation-degree display of a time constant. CONSTITUTION:The oscillation period of oscillation circuit 34 is varied by adjusting variable resistance 39 of time constant circuit 40 and its output is applied to divider circuit 35. Lines 41 and 42 are grounded through jumper lines 18 and 19 and a division ratio is set by switching depending upon their combination. An output from circuit 35 is counted by counter circuit 36 and when its count value reaches a preset value, transistor 25 conducts by its output to drive relay 26, thereby controlling an external load. Further, time elapse display unit 45 is connected to circuit 36 and elements 16 are lightened in sequence in accordance with the count value of counter 46. Variable resistance 39 employs a rotary system and its rotary axis is provided with a scale plate for time display. This scale plate can be replaced in accordance with division-ratio setting of circuit 35. Consequently, the set-time range of the timer can easily be changed.</p> |
