Ignition system for IC engine - has auxiliary switch out of phase with main switch to ensure decay of prim. current of ignition transformer

摘要

The ignition system has a switch (2) connecting the first end of the primary of the ignition transformer to the d.c. supply. An auxiliary switch (13) connects the second end of the primary via a diode (16) to the same pole of the d.c. supply and is operated out of phase with the main switch i.e. then the main is open, the auxiliary switch is closed. The auxiliary switch ensures that the current in the primary dies away. A second diode (17) connects the primary's first end to the second pole (earth) of the d.c. supply. Alternatively, the main and auxiliary switches may both be open at the same time, in which case a transistor circuit is incorporated to achieve the wanted current decay.