| 摘要 |
PURPOSE:To detect fault of a thermistor or circuit break by incorporating hot water oriented thermistor and overheat protection thermistor into a bridge and by detection of a potential difference at the midpoint of a bridge circuit. CONSTITUTION:A bridge is formed by serial circuits consisting of a hot water oriented thermistor 3, resistors 20, 17 and 18 and the bridge connected to a comparative amplification circuit 14 forms a hot water oriented thermistor circuit, and an overheat protection thermistor circuit is formed by a serial circuit composed of an overheat protection thermistor 6, a resistor 21 and a transistor 16, of a serial circuit consisting of a hot water oriented thermistor 3 and a resistor 20 and of a comparative amplification circuit 15. Numeral 1 represents a power source, 11 a keep-relay 13 which makes and breaks a contact 12 and numeral 13 a burner control circuit. |
