| 摘要 |
PURPOSE:To obtain an inexpensive burning proportion controller having high accuracy by using the temperature detected at a place near a heat exchanger to the control of duty using a solenoid valve after giving the digital conversion to said temperature through a ladder circuit and a microcomputer. CONSTITUTION:The temperature of supplied hot water is detected by a thermistor 12, and a desired reference temperature is set with free switching at a set temperature part 22. The signal corresponding to the set temperature is amplified by an operational amplifier 23 and supplied to a terminal of the plus side of a comparator 24. Each reference voltage decided by the number of ladders constituting a ladder circuit 25 is supplied to a terminal of the minus side of the comparator 24. The comparator 24 produces a signal at a coincident point with the signal sent from the amplifier 23 and then generates a digital signal in response to the set temperature. The ladders are successively scanned in a microcomputer 13, and the coincident point of signals is confirmed. In this case, the duty is controlled by a digital signal and a solenoid valve 27. |
