| 摘要 |
<p>PURPOSE:To obtain a duty detection output stably even when the magnetic characteristics of a saturable reactor vary. CONSTITUTION:A magnetic multivibrator circuit 21 oscillates invariably at a period T=4.n.phim/Ec, where Ec is a coil impressed voltage and phim is saturated magnetic flux. When the polarity of a primary current flowing through a primary coil 32 is equal direction to that of a secondary current flowing through a secondary coil 33 by the primary coil 32, the secondary current decreases and a tertiary current flowing through a tertiary coil 32 increases to the contrary. A connection point 37 is connected to a common emitter transistor (TR) 53 through the resistance 52 of a duty detecting circuit 23, and a DC voltage Vcc is impressed to the collector of the TR53 through a resistance 54. The DC voltage Vcc is divided by resistances 58 and 59 to apply an optionally set discrimination level V1 to the other input of a comparator 60, whose output based upon the discrimination level V1 is supplied to a driven device 26 through resistances 61 and 62. The DC voltage Vcc is divided by resistances 63 and 64 to apply an optionally set discrimination level V2 to the other input of a comparator 65. The output of the comparator 65 based upon the discrimination level V2 is supplied to the driven device 26 through resistances 66 and 62.</p> |
