| 摘要 |
PURPOSE:To insert the parallel circuit of a diode and a current control resistor between the emitter of a power transistor and a primary coil for preventing the excessively-early ignition due to the backward induction voltage generated in the primary coil. CONSTITUTION:When a fly-wheel 1 starts, the variation of magnetic flux occurs to a primary coil 3, and currents I2 and I1 flow in the order of mention. When a thyristor 11 has made continuity at a proper time (ignition time) while current I1 is flowing, power transistors Tr9a and 9b turn off to cut off current I1. Then, high voltage is induced in a secondary coil 4, and spark is generated on an ignition plug 7. If backward voltage is induced in the primary coil 3 at this time, a limited amount of the current I2 by a resistor provided in the parallel circuit of a diode 10 and a current control resistor 20 flows to the primary coil 3 from the base of the transistor Tr9b through a corrector so that the ignition generation of the ignition plug 7 can be prevented. |
