| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide an inexpensive ignition coil which prevents a spark plug from generating sparks owing to an ON voltage with a simple structure of lower energy loss. SOLUTION: A Zener diode 13 is electrically connected to the lower tension side of a secondary coil 12 so as to employ an ON voltage as its reverse voltage. When a switching signal applied to the base of a switching transistor 20 is set ON, a primary coil 11 gets energized to generate in the secondary coil 12 an ON voltage which is applied to a spark plug 21. The withstand voltage of the Zener diode 13 is set to 500V and the ON voltage is set below 1.18kV to prevent the spark plug 21 from generating sparks at moments other than predetermined ignition timing. The smaller size of the Zener diode 13 because of its flake, bare chip type permits its mounting on a substrate in an igniter.</p> |
