PURPOSE: To ensure the ignition by an arrangement in which if a power source switch is once opened and again closed, the spark electrical discharge is stopped without fail at a moment close to a set time.
CONSTITUTION: When a power source switch 3 of a DC-DC converter 1 is closed and a voltage of DC current for the timer actuation which is higher than the voltage of a battery 2 is supplied, a voltage from a condensor 26 which is charged in a time period determined by a CR time constant of a resistor 25 and the condensor 26 is applied between anode A and cathode K of PUT22. This will cause the PUT to be closed, and a predetermined voltage is applied to a gate G of a switching element 21, causing the switching element 21 to be closed. Then, the base voltage of an oscillating transistor 4 is controlled by a voltage between anode A and cathode K of a second switching element to terminate the oscillation. As a result, the spark electrical discharge at discharge electrodes 11 is stopped.
UEDA HIROSHI
NAKA CHIYUUJI
