| 摘要 |
<p>PURPOSE:To avoid the shortage of the time of electric current flow during the power is off and eliminate the shortage of hot water by driving a heat generating element by AND signal of the output of a second comparator which judges and compares the clock counting from the start of energizing by the midnight electric power and the inversion signal of the midnight electric power. CONSTITUTION:A clock counting section 7 is reset by the build-up of the output in a midnight electric power. A first comparator 8 compares the result of the calculation by an arithmetic unit 5 and the value of the clock counting, and when the clock counting value exceeds the calculation value, a signal is outputted to a heater drive circuit 9, and the heater drive circuit latches this signal to drive a heater 2. A second comparator 10 compares the clock counting value with a specified time, if the clock counting value has not reached the specified time, it outputs 'H' signal as an output. The output of an AND circuit to which the output of the second comparator and the reverse signal of the output of the midnight electric power circuit 6 are the inputs is given as a drive signal to the heater drive circuit. On the other hand, a water temperature sensor circuit 4 outputs OFF signal to the heater drive circuit 9 when the water temperature reaches a set temperature to stop the heater.</p> |
