Suzuki GS850G Service Manual page 316

FULL-TRANSISTORIZED IGNITION SYSTEM
A fully transistorized ignition
system
is now employed on the GS850G. I t s primary advantages are:
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* Trouble free operation due t o ~liminaiion of contart breaker points which can become contaminat~d.
*
Ignition timing is maintained properly at at! times and require no maintenance.
*
Free from arcing and provides the ignition coil with stable secondary voltage.
*
Excellent vibration and moisture resistance.
Transistor functions can be divided into four main, functions:
1. amplification
3.
oscillation
2. switching 4. modulation
These functions are utilized in the ignition system employed on the GS8SOG.
Transistors are divided into
two
groups, those being of the NPN
and PNP
types,
and
the transiston used
in the
GS850G model is of the NPN
type only, works an amplifier and switching device.
El : BASE
C : COLLECTOR
E : EMlTTE R
Each transistor has three terminals identified as t h e
Base
(B), Collector (C), and Emitter (E), and opera-
tion
is
as follows:
On a NPN type the base is the controling terminal of the transistor operation. On this type, the base
utilizes on!y a positive or incoming signal to do the "ON",
or
"0FF'"itching. The collector is the
terminal where voltage is supplied to the transistor and the emitter i s the terminal for passing this current
for usage when the base has the proper "signal". 'Usually the voltage applied across the collector to the
emitter i s much larger than that needed at the base. This allows a relatively low voltage a t the base to
control large working voltages across the collector t o the emitter.
The transistor ignition system used on the GS850G
is (the Nippon Denso brand
and) consists of a signal
generator, which ernploysa rator and two pick-up coils, the transistor unit, ignition coils, and spark plugs.
SIGNAL GENERATOR:
The signal generator is
mounted on the right
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hand side of the engine in the area commonly
used for the contact breaker points.
It is com-
ow
O N
prised of an iron rotor attached t o a mechanical
advance mechanism and two pick-up coils, with
FUSE
magnets at their bases, affixed to a plate. Each
pick-up coil consists of a coil or wire and
a yoke
or coil and is mounted
180"
apart on the plate.
SIGNAL
As
the
rotor tip is turned past
the coils, AC
GENERATOR
1
B I W ~ ~ ~ ~
COIL
3
I
current is produced and used for switching with-
in the transistor unit.
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The transistor unit controls power to the igni-
tion coils and causes the spark plugs t o fire at
the proper time.