| 摘要 |
PROBLEM TO BE SOLVED: To lessen the influence of floating capacity by wiring in an ignition detector using a switching power source, by making the output of the switching power source which has an oscillatory transformer sine waves or roughly sine waves where the frequency and the voltage values are severally within the specified value range. SOLUTION: The output of a switching power source which has an oscillatory transformer 12 is made sine waves or roughly sine waves within the range of 10KHz to 30KHz for frequency and 150V±30V (300V±60V in terms of peak vs. peak value) by single-side peak value for voltage value. By doing it this way, the influence of floating capacity 40a and 40b is lessened, and it becomes possible to maintain the voltage of AC 100V or over at the place of electrodes 31a and 31b for detection of ignition, and even if the lengths of wirings 32a and 32b become long to about 1m, the voltage between the gate and source of depletion type of FET's 21a and 21b for detection of ignition becomes negative by the rectification of a flame current at ignition, and the FET's 21a and 21b are turned off, and the ignition detecting action can be kept.
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