EH12, EH17, EH25 - Small Engine Discount

2) At the higher engine speed
Rotation of the flywheel generates the current I, as this current flows through the base terminal of the
power transistor, it is activated and the current IZ starts of flow.
As the engine reaches the ignition timing, the ignition timing control circuit for the higher engine
speed is activated and provides the base current Is to the power transistor. This current induces the
coIlector current 16 and will bypass the current I, to shut down the current Ir abruptly because the
power transistor is turned off.
This sudden current change generates a big voltage on the secondary side of the ignition coil and
which will spark the spark plug.
The ignition timing control circuit for the higher engine speed is activated sooner than the control
circuit €or the lower speed and not activated when the engine speed is in a lower range.
(B.T.D.C.)
L
ELECTRONIC ADVANCING FLYWHEEL
MAGNETO SYSTEM
STEP ADVANCING
15'1 , , , ,
500 1000 2000 3000(r.p.m.)
ENGINE REVOLUTION
Fig. 6-2 (b)
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