| 摘要 |
A capacitor (C1) of an ignition circuit (3) is charged by an output at a positive half cycle of an exciter coil (104), and the electric charge of the capacitor (C1) is discharged through a thyristor (Th1), whereby an ignition operation is carried out. When the level of a detected value (Vb) of the output voltage at a negative half cycle of the exciter coil coincides with the level of a reference voltage (Vr), a transistor (Tr4) is conducted so as to generate a reference signal. A measurement of an ignition timing calculated by a microcomputer is started at a reference signal generating position, and when an ignition timing is measured, an ignition signal is sent to the thyristor (Th1) to thereby start an ignition operation. The reference signal generating position is maintained constant by changing a reference voltage (Vr) in accordance with the output voltage and output frequency of the exciter coil. <IMAGE> |
