| 摘要 |
PROBLEM TO BE SOLVED: To restore a power source circuit without exchanging a protective device with another, when a load returns to a normal state by restoring the state of a restorable fuse by isolating an AC power supply switch, when the restorable fuse blows out. SOLUTION: When a large current exceeding the capacity of a restorable fuse 5 flows transiently to a power source circuit due to a surge current, etc., caused by the discharge in-tube, etc., of a cathode-ray tube, the fuse 5 blows out to protect the power source circuit. Consequently, the power at an AC power input terminal 1 is not supplied to a rectifying and smoothing circuit 2, and the output voltage of the circuit 2 abruptly drops to zero. When the fuse 5 blows out, a protective circuit 6 isolates a switch 4 by detecting the output voltage drop of the circuit 2 caused by the blown-out fuse 5. When the switch 4 is isolated, the power at the AC power input terminal 1 is not supplied to the fuse 5, and when a fixed period of time has elapsed, the blown- out fuse 5 returns to the original continuity state.
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