Capacitive discharge ignition system with shunt track on printed circuit board

摘要

A capacitive discharge ignition system, comprisesBR ```a step-up transformer (T), a capacitor (3) connected in series with the primary winding (5) of the transformer between terminals for receiving an energising voltage, and a control circuit (1) for controlling the charging of the capacitor, and for controlling the discharging of the capacitor through the primary winding to induce a high tension voltage in the secondary winding of the transformer for application to one or more spark gaps. The system comprises a printed circuit board (PCB) upon which at least some components of the control circuit are mounted. The printed circuit board has at least one conductive region (25) which in operation is coupled to the high tension voltage, and a shunt track (30) connected to one of said terminals or to a reference voltage terminal. The shunt track is adjacent, to but spaced from, the said at least one conductive region (25) for diverting to the said one of the terminals or to the reference voltage terminal any high tension current which flows from the said at least one conductive region to the shunt track. The shunt track (30) has a smoothly curved periphery to minimise its impedance at high frequency.