| 摘要 |
PROBLEM TO BE SOLVED: To provide a power unit which can control a plurality of devices, even when the size or cost of the unit is not increased. SOLUTION: A fluorescence lamp FL is turned on at a high frequency, by applying a high-frequency AC upon the lamp FL in accordance with the resonance characteristics of a choke coil L2 and a capacitor C7, in such a way that the AC voltage of commercial AC power supply (e) is full-wave rectified by means of a full-wave rectifier 3 and smoothed by means of a capacitor C3, and field effect transistors Q1 and Q2 are controlled by outputting rectangular waves from a microcomputer 8. The output of an inverter circuit 4 is changed with a control signal inputted to a signal-inputting circuit 9. Since the control signal corresponding to the control signal inputted to the signal inputting circuit 9 is outputted from a signal-inputting circuit 15 via a buffer circuit 16, it becomes unnecessary to turn the current of the control signal into a heavy current. Since the length of, for example, the signal line used in one device for connection can be shortened, the adverse effect of the distortion of signal or the resistance on the signal line can be prevented, and the control by means of the control signals can be made positively. |
