The Fascinating Evolution of Automotive Wiring
Summary
TLDRThe script traces the evolution of automotive electrical systems over time, from the basic wiring in early 20th century cars like the Model T to the sophisticated digital systems in modern vehicles. It examines key innovations that advanced wiring and connectivity in cars, including improved insulation materials, crimped terminals, aviation-inspired connectors, multiplexed communications networks, and standards for emerging electric vehicle systems. The complex wiring harnesses and networks in today’s cars grew out of incremental enhancements in materials, manufacturing, and design over decades of automotive development.
Takeaways
- 📈 The Ford Model T's electrical system evolved over time from a minimalist starterless design to one incorporating more sophisticated components
- 🔌 Early automotive electrical systems used cloth-covered copper wiring and screw/solder terminals which were unreliable
- 💡 Bullet connectors were an early improvement, allowing quick connect/disconnect of wiring without soldering or screws
- 📏 Crimping terminals became popular in the 1930s as it was faster, more reliable and provided strain relief
- 🔌 Aviation influenced automotive electricals - adopting circular connectors and higher quality insulated wiring
- 🌡 New insulation materials like PVC were introduced to replace less flexible rubber and handle higher temps
- ⚙️ More vehicle electronics in the 50s-70s required multi-pin plastic connectors and dedicated engine wiring harnesses
- 🤝 Serial bus protocols over the 80s-90s enabled advanced diagnostics, multiplexing signals over fewer wires
- 🔋 Hybrid and electric vehicles have required new standards for high voltage systems, connectors and charging
- 📈 Small iterative changes over decades transformed basic automotive electrical systems into today's sophisticated networks
Q & A
What was the first mass-produced electrical system incorporated into the Model T Ford?
-The first mass-produced electrical system in the Model T Ford consisted of basic wiring that integrated a magneto powered ignition system, lighting, a horn, a generator and battery combination that was used to primarily drive the starter motor.
How did early automotive electrical systems exhibit a trajectory towards growing sophistication and complexity?
-Early automotive electrical systems grew more sophisticated and complex by incorporating components like starters, lighting, horns, generators and batteries over time. The Model T Ford launched with a minimalist configuration and gradually added more components found in modern vehicles.
What were some drawbacks of the cloth-covered wiring used in early automobiles?
-Drawbacks of early cloth-covered wiring included deterioration over time leading to shorts and failures, less protection against abrasion and chemicals compared to modern wiring, bulky wire terminals prone to failure from vibration and heat, and susceptibility to contamination and corrosion.
How did crimping terminals help improve automotive wiring reliability?
-Crimping terminals provided a quicker, more reliable method of connecting wires that avoided heat application, ensured consistent and uniform connections, retained flexibility near connections preventing fatigue cracks, and captured insulation providing strain relief.
When were multi-pin connectors first adopted in automotive wiring systems?
-Multi-pin connectors were first adopted in vehicle wiring systems in the 1950s, when vehicles began incorporating more electrical components like radios, power windows and climate control systems, requiring complex wiring harnesses.
How did the use of computers and networking benefit automotive electrical systems?
-The use of computers and networking allowed functions like diagnostics and communication between electronic modules. Multiplexing networks let multiple data channels share one physical channel efficiently.
What are some key differences between networks used for critical versus non-critical vehicle systems?
-Critical systems like ABS and engine management require robust, low latency networks like CAN bus, while non-critical systems can use simpler, lower speed networks. Infotainment uses high speed networks to handle data rates.
How have standards facilitated development of electric vehicle technology?
-EV standards define communication protocols, connectors, charging infrastructure to enable interaction between EVs and charging stations. Safety standards mitigate risks with high voltage systems.
What are some examples of gradual changes that advanced automotive electrical systems over time?
-Changes like new connector and insulation materials, crimping and strain relief techniques, adoption of electronics and multiplexing led to today's sophisticated digital vehicle systems.
How can understanding measurement and analysis concepts help with learning about technology?
-Grasping measurement and analysis builds intuition around quantifying information in meaningful ways, which helps unlock complex technical concepts across many fields.
Outlines
🤩 Early Automotive Electrical Systems
This paragraph provides an overview of early automotive electrical systems, focusing on the Ford Model T. It discusses the evolution of the Model T's electrical system over its production span, highlighting the use of cloth-covered copper wiring, stranded wire for flexibility, soldered ring terminals, and rubber insulation. Key aspects like system reliability challenges and trajectory towards complexity are noted.
⚡ Improving Durability and Reliability
This paragraph explores the improvements made to enhance durability and reliability of automotive wiring from the 1930s onwards. Key developments include bullet connectors for reduced failure points, crimped terminals for better connections, spacer terminals for tight spaces, and aircraft-inspired circular connectors for complex systems.
🔌 Revolutionary Plastic Insulation
This paragraph examines the revolutionary introduction of plastic wire insulation in the 1920s/30s and its superiority over previous materials. PVC is highlighted as an early popular choice, offering flexibility in manufacturing and broad temperature/voltage range, though some drawbacks like degradation and toxic fumes when burned are noted.
🤝 Multi-Pin Connectors for Complexity
This paragraph discusses the need for multi-pin connectors as vehicles incorporated more complex electrical systems like radios, wipers etc. The use of inexpensive plastic connectors with nylon shells, spade terminals and locking clasps is outlined, though their durability limitations compared to aviation connectors are acknowledged.
📡 Digital Networks and Multiplexing
This paragraph focuses on the proliferation of digital networks and multiplexing from the 1980s onwards to manage growing electronics complexity. CAN bus is highlighted as an industry standard for inter-module communication. The need for specialized wiring to handle digital signals is also examined.
Mindmap
Keywords
💡Electrical system
💡Multiplexing
💡Insulation
💡Connectors
💡Diagnostics
💡Electric vehicles
💡Stranded wire
💡Crimping
💡Polyvinyl chloride (PVC)
💡Controller Area Network (CAN bus)
Highlights
Early automobiles used cloth-covered copper wiring which was flexible but prone to deterioration
Stranded wire was developed in the 1800s for applications needing flexibility and durability against vibration
Bullet connectors were an early connector system without fasteners, improving durability through vibration resistance
Crimping revolutionized connections by ensuring consistent, durable metal-to-metal contact without solder's rigidity
Circular connectors were adopted from aviation for their durability, ease of assembly, and replaceability
PVC wiring insulation was introduced in WWII, offering abrasion and chemical resistance at a low cost
Multi-pin nylon connectors enabled integration of new electronics like radios and climate control systems
Higher circuit complexity required dedicated signal wires and shielding against electromagnetic interference
Controller Area Network (CAN) bus improved reliability and noise immunity for digital communications
Multiplexing networks allowed multiple controllers to communicate, enabling telematics and diagnostics
High-bandwidth automotive networks use Ethernet or FlexRay as ADAS systems handle video data
Connecting EVs have led to new standards for communications, charging infrastructure, and safety
Despite shifts to electrification, wiring remains critical as improvements enable complex digital systems
Frequent small changes over decades established foundations for today's sophisticated vehicle electronics
Learning by problem solving, not just watching, is key - Brilliant courses unlock this through interactivity
Transcripts
this episode is brought to you by
brilliant this diagram represents the
first mass-produced electrical system in
human history it was incorporated into
the most common variants of the Model T
and it consists of basic wiring that
integrated a Magneto powered ignition
system lighting and the horn and a
generator and Battery combination that
was used to primarily Drive the starter
motor over its 19-year production span
with 15 million units produced the Ford
Model T's electrical system had evolved
drastically initially launched with a
starter lless minimalist configuration
it would gradually incorporate
components that can be found in the
electrical systems of modern vehicles
even from its early Beginnings
Automotive electrical systems exhibited
a clear trajectory towards growing
sophistication and
complexity early automobiles including
the Ford Model T used cloth covered wire
this type of wire consists of a copper
conductor insulated with a layer of
cloth material the cloth insulation was
typically made from cotton or a similar
fibrous material and impregnated with a
varnish or rubber to provide additional
protection against moisture and
wear while solid copper conductor wiring
was commonly used in the vast majority
of applications at the time Automotive
wiring was made of stranded wire
consisting of multiple small wires
stranded wire was developed in the late
1800s to address the limitations of
solid wire particularly in applications
requiring flexibility and durability
especially when exposed to vibration
cloth covered wiring impregnated with
rubber specifically proved to be ideal
for automotive use as its flexibility
made it easier to route through confined
and complex spaces these wiring
assemblies were typically connected to
components via a termination that
consisted of a a solder on ring terminal
that was fixed by screws with longer
spans of wiring being secured with metal
clips and even Stables this technique
was used even on high voltage ignition
wires fully rubber covered wire was also
developed as a more durable insulation
option and while it was Superior in
flexibility and insulative properties
over cloth-based variations rubber
insulation became brittle and cracked
over time especially when exposed to
heat heat light and certain
chemicals early automobiles were
notoriously unreliable and their
electrical systems greatly contributed
to this over time cloth insulation
deteriorated especially if exposed to
moisture in oils leading to a risk of
shorts and electrical failures cloth
insulation also offered less protection
against abrasion and chemical exposure
when compared to Modern insulation the
wine terminals used were bulky and
suffered from failure due to fatigue
caused by vibration and Heat heat
cycling this also caused Threaded
Fasteners to back out breaking
electrical connections these Junction
points were also susceptible to
contamination and corrosion further
diminishing
reliability in the 1930s bullet
terminals were one of the first Fastener
less connector systems to appear on
vehicles bullet terminals consists of a
male component the bullet and a
corresponding female component the
socket or sleeve into which the bullet
fits snugly these connectors are usually
made from soft Metals such as brass or
tin-plated brass which are chosen for
their good electrical conductivity and
resistance to corrosion the exterior of
the connector often features an
insulation sleeve made of vinyl or
rubber to protect the
connection a variant of the concept
called Spade terminals would also be
developed that permitted a connection to
be used in tighter spaces and harsher
physical
environments spay terminals consist of a
flat spade-shaped male connector that
places the mechanical connection to the
outer ends of the terminal via a
barrel-shaped spring light clamp on the
female end while the center of the
terminal forms the primary electrical
connection many versions also
incorporate a third Center locking
mechanism along the terminal's body for
a more positive connection particularly
in high vibration environments the
lowprofile nature of space terminals
allow them to be made into tighter reach
variations such as 90° flag style Spade
terminals the 1930s also saw the
introduction of crimping to terminate
wire terminals crimping involves
mechanically compressing a terminal
around a wire to ensure a metal toetal
contact it offers a quicker and more
reliable method for making connections
especially in production environments
where speed and repeatability are
essential it avoids the application of
heat and when done correctly provides
excellent mechanical strength and a high
degree of resistance to vibration and
pulling forces crimping also ensures a
consistent and uniform connection
reducing the risk of cold joints or
other soldering defects that can lead to
failures it also retains the full
flexibility of the wire near the
connection Point unlike soldering which
can create rigid sections that may be
prone to fatigue and cracking under
stress crimp terminated connections not
only made vehicle wiring far more
serviceable and cheaper to manufacture
but also dramatically increased
reliability through the inherent strain
relief they provided by capturing a
wire's insulation within a crimp the
stresses and strains placed on the cable
are prevented from being transferred to
the conductor dramatically reducing
freeing breaking or pulling out from the
terminal additionally strain relief is
also provided by any sleeves used on the
terminal
Junction towards the end of the decade
aircraft electrical systems were growing
so complex that single Junction
connections were becoming impractical
especially for military use electrical
Aviation components sometimes required a
dozen or more connections all of which
had to be easily disconnected for
service while remaining securely
connected in harsh environments this was
especially critical in combat
situations in the US aircraft
manufacturers would ultimately adopt a
solution that was traced back to the
early days of the motion piture industry
back in the 1920s Studio lighting
required a connector that could not be
accidentally disengaged this need was
met in 1925 with the introduction of a
receptacle and a plug with a mechanical
locking ring called the M series it was
developed by Robert Canon the founder of
Canon electric by the late 1920s
Paramount Studios developed its own
pseries connector for a new sound camera
that utilized a latched locking device
while Fox Studios would introduce its
own threaded coupling ring
variant from these Concepts the threaded
ring circular connector design was found
to be best suited for Aviation and would
be first used on the Douglas dc1
aircraft circular or cylindrical
connectors consist of two mating halves
or shell Each of which contains multiple
pins or socket configurations internal
insulating spacers initially made of
hard rubber support the contacts in
their proper orientation the plug end is
attached to a wiring bundle while the
receptacle is often mounted in a fixed
position such as on a panel or case the
plug consists of a barrel a coupling nut
and a backend termination the barrel
fits inside the receptacle shell and the
coupling nut holds the mated pair
together alignment of pins and sockets
must conform to rigid tolerances during
the manufacturing process in order to
avoid bending or breaking during
separation or closure of the two halves
wires are attached to the individual
contact pins by crimping or soldering
and are held in place by either an
interference lock a contact lock or an
insert lock the locking mechanism
determines how the pins are inserted the
shells were usually fabricated from
aluminum or steel and were extremely
rugged and were also polarized to
prevent mismatching and to make assembly
easier the success of these connectors
led to the United States Department of
Defense establishing military
specifications to create a supply of
standardized components with defined
housing dimensions and pin layouts
specifically designed and tested to
withstand the reliability performance
and environmental requirements of the
application for which they were intended
the first of these military
specifications was the a 9534 which
appeared on November 1st 1934 the
specification was superseded 2 years
later
bywc 591 which was was used with various
revisions for the duration of World War
II the growing importance of air power
during the war led to the establishment
of the US Air Force as a separate branch
of the military with a whole new set of
connector requirements in 1949 Mill c515
superseded AWC 591 and became the first
coordinated connector specification
approved for use by all three services
Army Navy and Air Force consider the
progenitor of all connector
specifications milc 515 covered a broad
range of pin contact sizes and voltages
up to 3,000 volt
AC the development and introduction of
synthetic polymers in the 1920s and
1930s marked a turning point for the
electrical industry as a whole Plastics
were found to offer Superior
characteristics over impregnated cloth
and even full rubber wire insulation it
was far more resistant to abrasion
electrical and thermal degradation and
unlike previous installations could be
chemically adapted to a broader range of
applications by altering its physical
properties one of the first and most
popular Plastics to be used for wire
insulation was polyvinyl chloride during
World War II PVC was introduced as a
replacement insulation for rubber as the
US lost access to 90% of the world's
natural rubber Supply its thermoplastic
properties made it very easy to
manufacture as it became more plastic
when heated and rigid again on cooling
it also allowed for the mixing in of
stabilizers plasticizers flame
retardants and lubricants to achieve a
broad range of properties PVC
instulation was designed to be resistant
to a wide range of temperatures from -4
de C to 125° C as well as to abrasion
moisture and Atmospheric agents
including UV rays it can also safely
insulate up to 1,000
volts PVC insulation however when
exposed to hydrocarbons and chlorinated
solvents can degrade or become brittle
leading to insulation failures it can
also become rigid and less flexible at
lower temperatures and when exposed to
fire PVC insulation produces thick black
smoke hydrochloric acid gas and it emits
dioxins which are highly toxic and can
cause health issues and environmental
damage during the 1950s Vehicles began
incorporating radios climate control
systems power windows wipers more
lighting and various other amenities
transforming vehicle wiring into its own
complex subassembly known as a chassis
wiring harness much like with Aviation
multi-pin connectors were needed but the
bulky and costly connectors used in
aviation were not viable for a consumer
product the solution came in the form of
the industry adopting its own range of
less costly plastic based multi-pin
connectors made from nylon these early
connectors were injection molded into a
pair of of rectangular mating shells
that housed Spade terminals that were
set in place by a contact lock on the
terminal body the shells were locked
together by a combination of friction
and a simple clasp that was captured in
an integrated aperture rubber boots were
often used to protect the connection in
exposed areas on a vehicle while these
connectors were far less durable and
were limited in terminal count when
compared to their Aviation counterparts
they were sufficient enough for
automotive use at the time over the next
two decades solid state Electronics
started to appear in vehicle electrical
systems initially within specialized
function components such as voltage
Regulators electronic fuel injection
drivers wipers and lamp and wiper
controls wiring harnesses were growing
denser and far more signaling and
sensing functionality became a part of
this new era of vehicles chassis wiring
harnesses were now designed using a
broad range of wire cross-section areas
insulation materials sheathing and
connector types to specifically
accommodate a section's application
while balancing cost and
reliability the mid 20th century also
saw the introduction of new wire
insulation materials based on propylene
polyethylene tetraethylene
hexafluoropropylene ethylene
tetraethylene polyurethanes polyesters
polyamides and synthetic rubbers that
all offered varying degrees of better
electrical characteristics greater
resistance to temperature abrasion and
hydrocarbons when compared to PVC with
some even allowing for thinner
insulation walls though these more
advanced insulations were used only when
needed due to
cost ethylene Tetra flu ethylene wire in
particular was adopted by Motorsports
alongside milspec circular connectors
due to its electrical properties
chemical inertness and exceptional
impact strength known as Tezel wire its
thin but tough insulation allowed for
less bulkier but extremely durable
wiring harnesses that could withstand
the extreme environments of
racing in the 1970s stricter fuel
efficiency regulations in the United
States forced car manufacturers to
improve engine efficiency and reduce
emissions when combined with the
exploration into the performance
benefits of fuel injection by European
manufacturers the progressive adoption
of electronic engine management systems
would occur over the next decade these
changes had a dramatic impact on wiring
complexity with electrical systems now
incorporating dozens of sensors and
control
mechatronics from this multi-pin
connectors were now capable of
containing up to 100 connections with
the pin and socket design becoming
standard similar to Aviation connectors
these use contacts made of precision
stamped and folded thin sheets of of
brass or copper Alloys that are formed
into cylindrical pins along with a
respective matching socket their mating
shells are generally rectangular though
more complex shapes are common with
equally various forms of integrated
keying for orientation pin and socket
connectors tend to use a combination of
contact locking and varying forms of
insert locking such as wedge locks this
was particularly important not just for
Positive Locking and ease of harness
assembly but also to distribute tension
forces evenly across the connector
body commonly made from either
polyamides polybutylene theerapat ABS or
nylon the Precision injected molded
shells employ one or more locking
mechanisms to secure the halves together
ranging from clasps to external locking
clips and even robust assembly Force
limiting locking mechanisms for larger
connectors much like their mspec
counterparts silicone or viton seals and
wire gaskets are also utilized to
weatherproof both The Mating and wire
termination end of the
connector with the proliferation of
digital engine management in the 1980s
chassis wiring harnesses now had to
contend with a new function the
transmission of digital signals and
highly susceptible analog sensor signals
this becomes problematic with relatively
inexpensive PVC insulations because of
its higher dialectric constant
dialectric constant indicates how
readily a material polarizes in an
electric field materials with a high
dialectric constants store more energy
but this can cause signal attenuation
and Distortion at high frequencies
additionally signal lines have to
operate in the electrically noisy
environments created by the ignition and
charging system and must be able to
handle cross talk from other Lines
within dense wiring
bundles to address address this wire
insulation materials such as
polyethylene and cross-link polyethylene
are favored for their low dialectric
constants offering minimal signal loss
at high frequencies for highly sensitive
signals such as in ABS sensors or nox
sensors signal lines are sheathed often
with grounded aluminum foil shielding to
mitigate the effects of electromagnetic
interference throughout the 1990s
computerization became integrated with
Automotive Electrical systems with
network topology slowly being adopted by
most
manufacturers in this model electronic
controllers were assigned to each
vehicle system and between them
multiplexing signal protocols allowed
for multiple channels of data to be
exchanged over a single physical
channel the First multiplex systems used
basic serial protocols derived from
Industrial Systems such as rs232 rs485
and rs s 422 these protocols rely on a
predefined fixed bit rate and some
connection management data to directly
transmit a stream of bits the simplest
form of this is known as single-ended
communication where a bit is represented
by a voltage level relative to ground
while this only requires a single signal
wire and is simple to implement its bit
rate is limited due to noise
susceptibility balanced serial
communication improves proves this by
using two signal wires that are often
Twisted together one carries a positive
signal and the other carries an inverted
signal any noise induced on the
transmission line affects both signals
equally allowing the receiver to
effectively cancel out the Noise by
subtracting the inverted signal from the
positive one this method improves noise
immunity and enables reliable faster
communication over longer distances when
compared to single-ended serial
communication in the the early 1980s
various Automotive serial communication
protocols emerged such as Kline line
j1850 which used pulse width modulation
and SE used by General Motors these
protocols facilitated Diagnostics and
intermodule communication but lacked
speed and
flexibility in 1986 controller area
network bus protocol or can bus was
released at the Society of Automotive
Engineers conference in Detroit
Michigan the developed by Bosch canbus
is known as a multimaster serial bus as
it permits multiple nodes to communicate
with each other over the same channel
robustly and without conflict canbus
employs two wires that carry opposite
bit States or a differential signal to
easily filter out noise the
specification also defines a messaging
protocol that encapsulates interm module
communication into frames with Advanced
features such as prioritized message
transmission and error detection by the
mid1 1990s it would be adopted by the
industry as the standard for in-vehicle
digital Communications with the standard
evolving over time to support higher
data rates and larger payloads by the
mid 2000s dozens of subsystems were now
common on vehicles with vastly different
requirements critical systems such as
ABS airbags traction control and engine
management require low latency robust
links while basic chassis electrical
systems can operate efficiently on low-p
speeded simpler Communications
infotainment systems in comparison
require High data rates but are not
critical because of this variability
modern vehicles Now operate multiple
networks with some even using fiber
optics to facilitate High data rates and
noise immunity a typical mid-2000s
vehicle configuration for example would
employ a can bus Network for critical
systems a single-ended low-speed serial
bus such as Lin for non-critical chassis
electrical control and human interface
and a fiber optic protocol such as most
for transmitting digital audio data
throughout an audio
system vehicle service and Diagnostics
has also benefited by the use of
multiplexing networks by allowing the
direct access to the control systems
within a vehicle from a singular
interface though this comes at the cost
of expensive diagnostic tooling training
and Reliance on manufacturers for
proprietary
Hardware as Advanced Driver assistance
systems or Adas began to appear in
vehicles high bandwidth links that are
capable of handling video data added a
new layer of vehicle networking two
common Technologies used for this are
standard ethernet adapted to vehicle use
and flexray high-speed deterministic bus
Network a can bus like system that is
designed for time critical applications
in
vehicles with the introduction of hybrid
and electric vehicles an entirely new
realm of evolving standards have emerged
that Encompass various aspects of EV
wiring including the design installation
and performance requirements of high
voltage wiring harnesses cables
connectors and Associated components
standards such as ISO
15118 IEC
62196 and IEC 61851 Define communication
protocols connectors and charging
infrastructure specifications to
facilitate seamless interaction between
EVs and charging stations additionally
standards like I 63110 and ISO
6469 establish safety requirements for
high voltage cables and electrical
systems in EVS to mitigate risks
associated with electrical
hazards the automotive industry is
experiencing a profound transformation
navigating the shift from traditional
combustion engines to electric power
while balancing performance and the
allore of driver experience with the
potential rise of autonomy however
despite this potential Paradigm Shift
one constant Remains the critical role
of wiring in
vehicles it's the little Progressive
changes over time that pushes an
industry forward the Automotive
Electrical industry is a perfect example
of this small changes in materials and
Designs over the decades laid the
foundation for the incredibly
sophisticated digital Vehicle Systems of
today and at the heart of any
advancement is the process of testing
and measurement building a strong grasp
of measurement and Analysis can be
complicated but there's a free and easy
way to get started immediately that's
where brilliant.org comes in
brilliant.org is my go-to tool for
diving head first into learning A New
Concept it's a website and app built off
the principle of active problem solving
because to truly learn something it
takes more than just watching it you
have to experience it brilliant is
constantly developing their courses to
offer the most visual Hands-On approach
possible to make mastering the key
Concepts behind today's technology
effective and engaging a great starting
point I highly recommend is brilliant
measurement course in this series of
lessons you'll unlock your sense of
perception and learn how to quantify
information in new more meaningful ways
using an intuitive set of exercises that
will change your perspective with
brilliant you learn in depth and at your
own pace it's not about memorizing or
regurgitating facts you simply pick a
course you're interested in and get
started if you feels stuck or made a
mistake and explanation is always
available to help you through the
learning process to try everything
brilliant has to offer free for a full
30 days and start learning stem today
visit brilliant.org newmind or click on
the link in the description below the
first 200 of you will get 20% off
brilliant's annual premium
subscription
浏览更多相关视频
Experience the future of autonomous vehicles, powered by 5G and Edge technology.
Stehen Hybrid-Autos vor dem Aus? - Bloch erklärt #239 I auto motor und sport
La fabbrica ELETTRONICA che tutto il mondo ci invidia 🇮🇹 | Dentro alla TEXA
EV Electrical Systems BASICS!
History of Embedded Systems [year-4]
SEJARAH PERKEMBANGAN ALAT TRANSPORTASI
5.0 / 5 (0 votes)