| 摘要 |
PURPOSE:To make it possible to determine the state of flame by applying a DC voltage across the burner and terminal with polarity being changed alternatingly and analyzing the wave shape of the resultant current by a microcomputer. CONSTITUTION:A voltage is applied across the burner 25 and terminal 26 with polarity being changed alternatingly. When there is flame at the burner 25, a current flows from the terminal 26 to the burner 25 if VA=VCC, and a voltage drop VFR is caused in a resistor 27 to make VB to be a voltage which is lower than VCC by VFR. If VA is at the GND level, VB becomes the GND level because of no flow of current from the burner 25 to the terminal 26 due to the rectifying action of flame. By processing the voltage VB generated by a current sensing circuit by an A/D converter circuit 29 and an analyzing it by a microcomputer 30, the state of flame, burner 25 and terminal 26 can be determined. |
