Abstract: An ignition system for an internal combustion engine comprising a battery, an ignition coil having a primary and secondary winding, a variable impedance element whose impedance is temperature dependent coupled between the primary of the ignition coil and the battery, and a set of distributor points coupled between the primary and secondary windings of the ignition coil and ground. The variable impedance element prevents deterioration of the ignition efficiency as the temperature of the ignition coil goes up, and can also prevent the temperature of the ignition coil from raising to a point wherein the ignition coil is damaged.

Abstract: There is provided an ignition system in which a light path is arranged so that the light output of a light emitting element is received by a photoelectric element, and this light path is made and broken intermittently to generate ignition signals. A plurality of weights or rockers are provided to intercept the passage of light in the light path. The weights are moved outward and inward by the centrifugal force which varies in accordance with the engine speed, and in this way the time interval during which the light is intercepted is varied. The duration of the light intercepting period is varied so that the dwell angle is increased as the engine speed increases. Consequently, even at the high engine speeds, the primary current in the ignition coil is not easily decreased thus preventing the decrease in the secondary voltage, and moreover the function of a centrifugal spark advance mechanism can be concurrently performed.