| 摘要 |
PROBLEM TO BE SOLVED: To obtain a desired voltage.SOLUTION: When an output voltage of a 12V power supply circuit 80b becomes a prescribed voltage or more, for example, DC 6V, after power activation, a transistor 84 of a relay drive circuit 83 is operated and current flows in a coil 82L of a relay 82. When the current flows in the coil 82L, a contact part 82S is switched from an opened state to a closed state by electromagnetic force of the coil 82. Accordingly, since both ends of a thermistor 76 shot-circuits, the thermistor 76 becomes invalid. In this way, when the relay 82 is driven, an electric circuit is switched from an electric circuit that passes only the thermistor 76 to an electric circuit that passes a parallel circuit of the thermistor 76 and the contact part 82S. In the electric circuit that passes the parallel circuit of the thermistor 76 and the contact part 82S, almost all current passes the contact part 82S, and current that passes the thermistor 76 is little (almost zero).SELECTED DRAWING: Figure 6 |
