| 摘要 |
PURPOSE: To prevent an erroneous detection on an apparatus which applies a measuring voltage to an ignition circuit in the secondary winding of an ignition coil and detects the existence of an ionizing current of the ignition circuit by interrupting an operation of a measuring device when a starting sequence is detected. CONSTITUTION: When a thyristor 22 or 23 is triggered by a trigger signal which is output from a trigger unit 6, a discharged electric current of a condenser 15 flows to the primary winding 12 or 13 of an ignition coil, then high voltage is induced at the secondary winding 30 or 31, and a spark is generated at ignition plugs 2 or 3. One edge of the secondary winding 30, 31 are connected with a ground through an measuring device 29 and an ionizing current of the ignition circuit is detected by the measuring device 29. In the occasion, positive control voltage is supplied from the trigger unit 6 to a transistor 63 and a point 62 is connected to the ground. Thereby, on the measuring device 29, an electrification to a measuring condenser 40 is prevented and the measurement of the ionizing current is interrupted. |
