| 摘要 |
PURPOSE:To obtain a stable performance even at low speed by making an electronic timing control circuit function ineffective when power voltage drops to a given value or below. CONSTITUTION:A power voltage drops and an output voltage of an electronic timing control circuit 2 also drops to the power voltage or below at a low rotational frequency which is capable of operating the electronic timing control circuit 2 erroneously, therefore a signal from the electronic timing control circuit 2 is blocked by a zener diode ZD2 and hence is not transmitted to a gate of a firing thyristor 6. In such a case, on the other hand, a signal from pulser coil 3 is applied directly to the gate of the thyristor 6 by way of a resistance R2 and a diode D5 and thus triggers it, therefore a stable firing operation is obtainable at a position before the spark advance. |
