| 摘要 |
PROBLEM TO BE SOLVED: To provide a portable light in which a light emitting diode employed as its light source reduces the intensity gradually as the voltage of the battery lowers. SOLUTION: By inserting a constant current diode corresponding to the standard current of a light emitting diode to be used in place of ballast resistor inserted in series with light emitting diode, a constant current is maintained to suppress the change in the quantity of the light regardless of the drop of voltage. |
