| 摘要 |
<p>PURPOSE:To realize a constant control of temperature regardless of an increase/ decrease of load for a temperature controller of an electric blanket or the like, by connecting each point of connection of plural temperature detecting circuits consisting of a series circuit of a heat-sensitive element and a resistance to an input terminal of a comparator via a change-over switch. CONSTITUTION:Impedance elements 23, 24 and 25 of the heat-sensitive elements or the like are provided close to loads 35, 36 and 37 which function as the heat generating conductors; and the number of power supply loads can be increased or decreased when necessary by change-over switches 26, 27 and 28. These impedance elements are connected in series toresistances 20, 21 and 22 and then to a power source, and these points of connection are connected to an input terminal of a comparator 31 via the switches 26, 27 and 28. The output of the comparator 31 drives a relay 34 via a transistor 32 to supply the power source to the load. As the ratio between the impedance element and the resistance is controlled to a constant value, the set temperature does not change regardless of the number of the connected loads.</p> |
