| 摘要 |
PROBLEM TO BE SOLVED: To provide a power unit which is compact and low-cost to the possible extent, while protecting the load of an electronic apparatus etc. from an overvoltage.SOLUTION: The power unit includes: an input part which inputs an AC current; a rectifier circuit for rectifying the input AC current into a DC current; and an overvoltage protection circuit 200 connected to the input part. The overvoltage protection circuit 200 includes: a fuse 210 connected in series with a power line L1; and a triac 220 which forms a current path P between power lines L1, L2, in response to the application of overvoltage. When an upper-limit overvoltage is applied, the rating currents of the fuse 210 and the triac 220 are selected so that the triac 220 is operated in a short-circuit mode. |
