Abstract: An ignition system breaker point assembly for an internal combustion engine to be mounted on the engine adjacent a rotating engine shaft is disclosed and includes an electrically insulating cam supported on the engine shaft for rotation therewith and an electrically insulating housing containing a movable contact member and a stationary contact member with a portion of the movable member extending from the housing toward the cam surface to be actuated by the cam for making and breaking electrical contact. The stationary contact may be adjusted from outside the housing for varying the breaker point gap and a spring may be included within the housing providing continuous electrical and mechanical contact with the movable contact member, urging that movable contact member toward the stationary contact member and the portion of the movable contact member which extends beyond the housing toward the cam. Desirably, the cam comprises an eccentric annulus of a self-lubricating electrically insulating material.

Abstract: An ignition system of the contactless interrupt type for an internal combustion engine is disclosed with a control circuit including a pair of solid state semiconductor devices with one connected to the other in a controlling relation. The ignition system has a high voltage transformer with a secondary winding coupled to a spark plug and a primary winding shunted by the controlled one of the pair of semiconductors. A current flow is induced in the primary winding and then interrupted near its maximum value by rendering both of the semiconductor devices nonconducting. The controlling semiconductor may be a gate controlled switch or so-called gate turn-off device while the controlled semiconductor may be a power transistor.