Solid-state stroboscope

EE June 1986 56 Fig. 1. The stroboscope basically consists of a pulse shaper (MMV1), a cylinder selector (IC2 and Si), and a flash section which operates with 24 pulse- controlled LEDs in a special con- figuration. 12V O 12 V 15 4 There is very little doubt that the `running engine", or stroboscope method for car ignition adjustment is much to be preferred over testing with a simple bulb, temporarily con- nected across the ignition coil primary winding; this would seem to be only suitable for the detection of gross malfunctions in the low-voltage ignition circuitry. More importantly, however, the test bulb method can only be performed with the engine switched off, which is an obvious disadvantage as compared with the stroboscope procedure. It should be noted, however, that the construction of a suitable circuit to supply the high-voltage pulse to the neon or xenon discharge tube is a fairly complex matter. The proposed design for the stroboscope, detailed in this article, therefor...