Test circuit for IC engine ignition system - has ignition suppressed until counter is synchronised with master cylinder

摘要

The test circuit, for an IC engine ignition circuit, has a counter synchronised to the engine ignition sequence. A blocking circuit (21) prevents ignition being suppressed in any one cylinder of the engine until the counter (19) has been synchronised with the ignition sequence. Only after the counter has been synchronised can testing proceed. The blocking circuit is controlled by a triggering signal from a master cylinder. This triggering signal is applied to the base of a transistor switch (22) that charges a capacitor (33).