| 摘要 |
<p>PURPOSE:To improve control characteristics by modulating the operation point of the differential circuit of a thermostat by a comparator which determines a duty ratio. CONSTITUTION:The thermostat 1 is formed of a deviation amplifier 2 and the differential circuit 3 and the contact 18 of a relay 17 is made and broken to drive and control a refrigerator 9. In this case, the differential circuit 3 has the comparator 11 which generates the duty cycle and compares a saw-tooth wave generated by the saw-tooth wave generating circuit 12 with the detected value of an ambient temperature sensor 13 to input the comparison output to the comparator 5 of the differential circuit 3 through a diode 14 and a resistance 15. Consequently, the comparator 11 generating the duty cycle varies the potential of the differential circuit 3 to causes the transition of its operation point, thereby reducing the width of control temperature substantially.</p> |
