Aston Martin V8 Vantage, Руководство по ремонту

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Wiring and Circuit Protection (18.01)
Electric Distribution/Electronic Control (18.00)
18-1-10 Workshop Manual October 2005
Motor
Diodes
The simplest way of describing a diode is ‘a non return
valve’. The current will flow through the diode from the
anode to the cathode, due to the construction of it though
current cannot come back. Diodes are used to reduce the
possibilities of ‘back feed’. This is where current comes
through the circuit the wrong way for one reason or another.
Below is the circuit symbol for a diode.
Light Emitting Diode (LED)
The light emitting diode (LED) works on the same principal
as the diode. The main difference is that in the
manufacturing process one of the materials is replaced by
another. This replacement material has certain properties
that when a certain voltage passes through it glows.
Transistor
A transistor in simplistic terms is a switch with no moving
parts. The ‘switching’ is controlled by electronics and
currents etc. rather than a physical switch being operated.
Below is the circuit symbol for it. The example shown below
is one of the most common basic type used called a
‘Bipolar’.
Field Effect Transistor (FET)
A field effect transistor (FET) is, in simplistic
terms, a switch with no moving parts. The
‘switching’ is controlled by electronics and
currents etc. rather than a physical switch
being operated. The main difference
between this and the type of transistor shown above is this
one operates using a magnetic field.
Earth / Ground
For an electrical current to ‘flow’ around a circuit it has to
start from a power source and go to an earth / ground. If
there are any breaks in this circuit then current will not flow,
this is called an ‘Open circuit’
There are 2 types of earth, Signal Earth and Chassis Earth,
these are referred to sometimes as a Quiet Earth and Noisy
Earth respectively.
Some sensors for example specify a Signal / Quiet Earth.
While components such as pumps and motors can have a
Chassis / Noisy Earth. The reason behind this is that pumps,
motors and the like can generate ‘electrical noise’ by the
way of their operation. Some of this ‘electrical noise can be
transferred through wires, it is this ‘electrical noise’ that can
have an adverse effect on sensor signals and affect the
control readings.
Keeping Signal / Quiet and Chassis / Noisy
earths separate reduces the effect of ‘electrical
noise’ being transferred from component to
component.
This symbol is a standard symbol for earths.
On the circuit diagrams some earths are shown as eyelets
with the description of Earth-**** next to it, the earths also
comply with the 4 digit C number. An example of this is
shown below.
= Anode
Cathode
Anode
Cathode
LED Colour
Arrow Symbol
indicating light
emission