| 摘要 |
PROBLEM TO BE SOLVED: To extend the replacement cycle of a battery, leave an apparatus compatible with intrinsic safety, and suppress increases in cost and apparatus volume.SOLUTION: A power circuit includes battery circuits 1-1, 1-2. Each battery circuit 1-1, 1-2 includes: a battery 2-1, 2-2; a constant voltage drop circuit 3-1, 3-2 for causing a constant voltage drop of a voltage of the battery 2-1, 2-2; a bypass circuit 4-1, 4-2 for selectively disabling the constant voltage drop circuit 3-1, 3-2; and a backflow prevention diode 6-1, 6-2 having an anode connected to an output terminal of the constant voltage drop circuit 3-1, 3-2 and a cathode connected to a positive side power terminal of a load circuit 7. The bypass circuit 4-1 of a service battery circuit 1-1 of the two battery circuits is set on, and the bypass circuit 4-2 of a standby battery circuit 1-2 is set off. |
