| 摘要 |
PROBLEM TO BE SOLVED: To provide an incandescent lamp capable of suppressing a rash current into a filament by automatically controlling current flowing into the filament. SOLUTION: An incandescent lamp 10 comprises a resistor member 12 connected in series to a filament 60 and arranged within a bulb 54 and a temperature-sensitive switch 14 arranged in the bulb 54, connected in parallel to the resistor member 12, and having a contact 14b opened and closed by a bimetallic element 14a. The bimetallic element 14a begins to deform due to heating of the filament 60 in response to the start of supply of current, during which time the contact 14b is transferred to a closed condition to establish a short-circuit of the resister member 12 when the temperature of the bimetallic element 14b reaches a predetermined value. In this operation, a rash current into the filament 60 is suppressed, because the current is supplied to the filament 60 through the resistor member 12 in the beginning. The incandescent bulb 10 is lighted bright after the short-circuit of the resister member 12, then this lighting state continues as long as the current is kept being supplied, because the temperature within the bulb 54 is avoided from being lowered.
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