| 摘要 |
PROBLEM TO BE SOLVED: To provide a small-sized power source circuit for lightening an LED with an AC source in which circuit heat generation is little, at a low cost. SOLUTION: Instead of a current limiting resistor of an AC power source 1, capacitive reactance of a capacitor 12 or inductive reactance of a coil 18 is used. A current-limited AC is rectified with a rectifier circuit 11, and lightens an LED 2. A constant voltage element 13 is connected in parallel with the LED 2. A rush current into the capacitor 12 generated at a phase when a power source is closed is bypassed, or a high voltage generated from the coil 18 is limited, thereby protecting the LED 2 from an excessive current. |
