| 摘要 |
<p>PURPOSE:To make a changing work of a substrate itself unnecessary, and to profitable workability and cost, by executing temperature control corresponding to each use by a single substrate. CONSTITUTION:A bridging circuit is constituted of resistances 3-6 and a thermistor 7. A comparator 2 inputs unbalanced voltage of the bridging circuit concerned, and outputs it to a relay 1A. (-) input voltage which becomes reference voltage of the comparator 2 is decided by fixed resistances 4, 5 and 6, and a variable resistance 12, this voltage is varied by operation of a variable terminal 12A of the variable resistance 12, and a set temperature in case of temperature control of a combusting circuit can be made variable. When the fixed resistance 5 is made to have a lower resistance value than the resistances 4, 6 and the variable resistance 12, a reference voltage value of the comparator 2 becomes almost equal to both in case when a set temperature is fixed and in case when it is variable, and it is unnecessary to change the fixed resistances 4, 5 and 6. Accordingly, the fixed set temperature and the variable set temperature can be used properly by changing them easily, by only attaching and detaching a jumper wire and the variable resistance 12 selectively.</p> |
