| 摘要 |
PURPOSE:To maintain the largest lag angle quantity constant by enabling a signal supply control transistor switch to be held in a shut-out condition without sending big short-circuit electric current to a signal coil which gives a control signal to the primary electric current control switch of an ignition coil. CONSTITUTION:An ignition position control circuit 20, controlling a thyristor 3 serving as the primary electric current control switch for an ignition coil 1 in an ignition circuit 5, is composed by providing a signal coil 23, which generats a control signal synchronizing with the engine speed, and a signal supply circuit, consisting of a resistance 26 and a diode 27 which generate a control signal different from that of the signal coil 23. A collector of a signal supply control transistor Tr28 is connected to one end of the resistance 26, while a semiconductor switch 30 for a base electric current by-pass is connected to the base of said collector. Further, voltage comparison circuits 53, 59 are provided for comparing the terminal voltage of lag angle control condensers 41, 42 charged through constant-current circuits 20A-20C with reference voltage and placing those control signals from the signal supply circuit on ON/OFF state. |
