| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To enhance safety by eliminating an unintended conduction state. <P>SOLUTION: By making a resistance load 3a to have a structure with either end of the resistance load 3a separated from an alternating-current power source 1 at the time of nonconduction with the use of two of a first and a second relays 2, 4 fitted at either end of the resistance load 3a for the connection between the alternating-current power source 1 and the resistance load 3a, even if one of the relays or a driving circuit breaks and has its contact to be in a continued closed state, unintended continuous conduction of the resistance load 3a is prevented by releasing the connection between the resistance load 3a and the alternating-current power source 1 through the other relay. In case of conduction with the resistance load 3a by driving the first and the second relays 2, 4 with the use of a microcomputer 11, if the resistance load 3a is to be in a state of continuous conduction due to runaway or latch up of the microcomputer 11, one of the relays can be surely in a nonconductive state. <P>COPYRIGHT: (C)2011,JPO&INPIT</p> |
