| 摘要 |
PURPOSE:To prevent to change the pulse generating input voltage by the ambient temperature, by applying a specific preset divided voltage to a two-way thyristor connected in parallel to a discharge lamp and to a condenser connected in series. CONSTITUTION:To the lighting circuit of a display lamp 114, a nonlinear condenser 134 connected in series, and a two-way thyristor 130 are connected in parallel, and a divided voltage by voltage dividing resistances 154 and 156 is applied to a resistance 134. The dividing ratio of the resistances 154 and 156 is set to make the voltage applied to the condenser 134 less than the highest resistance voltage of the service temperature scope of the condenser 134 when the thyristor 130 is made at a breakover voltage, making it possible to operate the condenser 134 after the thyristor 130 is operated at first, resulting in no change of the pulse generating voltage even though the ambient temperature is lowered, and a condition to raise the pulse generating voltage so as to generate no pulse can securely be avoided. |
