| 摘要 |
<p>PURPOSE:To avoid the shortage of conduction time due to the service interruption of midnight electric power, by providing a comparator generating an output when the counting unit of a clock has exceeded a predetermined time. CONSTITUTION:A comparator (2) 10 outputs when the count of a clock has exceeded 7hr. An AND circuit 11 inputs the output of the comparator (2) 10 and the converting output of a midnight electric power detecting circuit 6 and the output thereof resets the counting unit 7 of the clock. When service interruption occurs within 7hr after starting the conduction of midnight electric power, the converting input of the midnight electric power detecting circuit is inputted into one input terminal of the AND circuit 11; however, an AND condition is not established since the result of comparison in the comparator (2) 10 has not arrived at 7hr of the count of the clock and the reset signal of the counting unit 7 of the clock is not generated. Therefore, the count of the clock may be continued even when the supply of the midnight electric power is started again transfer, whereby the shifting time of the conduction of a heater 2 may be secured correctly.</p> |
