| 摘要 |
PROBLEM TO BE SOLVED: To provide an reliable equipment which can be used under different voltages. SOLUTION: An AC power supply AC is connected to a smoothing capacitor Ci via a diode bridge circuit Di. About an EE-type ferrite magnetic core which constitutes an insulating converter transformer PIT, a central leg portion of the core is shorter than two pairs of outer leg portions to form a gap for loose coupling between a primary winding and a secondary winding. A center tap of the primary winding T1 is connected to the positive side of the capacitor Ci through a choke coil CH. One end of the primary winding T1 is connected to a switching transistor Q1, and a resonance circuit comprising at least an output voltage stabilizing means is connected to the transistor Q1. The other end of the primary winding T1 is connected to a switching transistor Q2 and another resonance circuit comprising at least an output voltage stabilizing means is connected to the transistor Q2 through a switch SW. The switch SW is controlled according to the voltage at the positive side of the capacitor Ci.
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