| 摘要 |
PURPOSE:To dispense with a large switching element and realize stepped light adjustment with simple constitution by providing a changing-over circuit which changes over a rectification method between full wave rectification and double voltage rectification in a rectification smoothing circuit and changing over the output of a lighting circuit by this rectification method. CONSTITUTION:The AC input of a power source A is rectified at a diode bridge in a rectification smoothing circuit F and smoothed at condensers C1, C2 and input into a lighting circuit B. Then, if a change-over circuit S is closed, the AC input of the power source A is rectified into double voltage, and voltage 2E double the power source voltage E is input into the lighting circuit B, and the output voltage of the lighting circuit B becomes full lighting voltage and a lamp La lights fully. On the otherhand, if the change-over circuit S is opened, the AC input of the power source A changes from double voltage rectification over to full wave rectification and the voltage E of the power source A becomes the input voltage of the lighting circuit B and the lamp La is changed over to lighting at step-adjusted light. Hereby, a switching element having large capacity becomes needless and step light adjustment becomes possible with simple constitution. |
