| 摘要 |
PROBLEM TO BE SOLVED: To provide the lighting device system which prevents costs from rising high, concurrently prevents the device from being large in size, and makes its leaking current small. SOLUTION: The AC voltage of a commercial AC power supply (e) is rectified by an all wave rectification circuit by means of all wave rectification so as to be smoothed by a smoothing capacitor C2 for allowing a fluorescent lamp FL to be lighted by means of high frequency with transistors Q1 and Q2 alternately switched by a control circuit 6. In a high frequency noise prevention circuit 3, the noise voltage of a noise source for radio frequency which is an obstacle to a television receiver, is thereby reduced after due consideration on stray capacity interspaced with the ground. The high frequency noise prevention circuit 3 allows leaking current by the stray capacity cx1 through cx5 of a discharge lamp lighting device 2 to be made smaller by a common mode choke Tr, and thereby prevents the occurrence of electrical shock. Since the capacity of capacitors C11 and C12 is roughly several ten times as large as the stray capacity Cx1 through Cx5, the stray capacity Cx1 through Cx5 is very small as compared with the capacity of the capacitors C11 and C12, imbalance is thereby canceled, and the common mode choke Tr is prevented from being saturated. |
