Transcript Implementing Logic Using Electronic circuits

Exploring Engineering
Chapter 9, Part 2
Logic and Computers
Implementing Logic Using
Electronic circuits
“This endless circulation of the
electric fluid may appear paradoxical,
But it is no less true and real, and you
may feel it with your hands.”
Allessandro Volta 1745-1827
Electric Circuits
Ohm's Law:
V Where:
I
R I is current in ampers,
V is voltage in volts
R is resistance in ohms ()
Power in an electrical circuit
Where:
P is power in watts
V is voltage in volts
I is current in ampers
Where:
I is current in ampers,
V is voltage in volts
R is resistance in ohm
Power in an electrical circuit
P V  I Where:
P is power in watts
V is voltage in volts
I is current in ampers
Electric Circuits Switch
Logic
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Switch open = input logic state 0
 Switch closed = input logic state1
 Lamp off = output logic state 0
 Lamp on = output logic state1
OR analogue circuit
B
A
L
• Lamp L off (state 0) unless either A or B closed
•This is an OR operation.
 Can you draw a circuit with an AND operation?
NOR (not or) Logic Function
Input A
Input B
Output
 Switch
not pressed = input logic state 0
 Switch pressed = input logic state 1
 Lamp off = output logic state 0
 Lamp on = output logic state 1
Relay Logic
Relay NOR Circuit
A input
B input
Battery
• Relay coil not energized = input logic state 0
•Relay coil energized = input logic state1
•Lamp off = output logic state 0
•Lamp on = output logic state1
Vacuum Tubes
Transistors
Inside Transistors
Transistor NOR Circuit
Output
Input A
Input B
Battery
•Gate Voltage 0 volts = input logic state 0
•Gate Voltage 5 volts = input logic state 1
•Output Voltage 0 volts = output state 0
•Output Voltage 5 volts = output state 1
Integrated Circuits
Only 7/16" wide and containing two transistors,
this unassuming integrated circuit was
nevertheless the first. It was mounted on a bar
of germanium and was demonstrated by TI on
September 12, 1958.
Complex Integrated Circuits
 Millions
of transistors
can be combined on
a single chip to
create a Central
processing Unit
 Integrated Circuits
can be fabricated to
act as storage for
program instructions
and data.
THE CPU
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The CPU (Central
Processing Unit) is the
complex integrated circuit
that makes something a
Intel 4004 chip
computer.
The CPU is the part of the
computer that processes
information, performs
Input
arithmetic calculations, and
makes decisions based on
information values.
The instructions and
information used by the CPU
are stored in computer
memory.
Permanent
Storage
CPU
Processor
Temporary
Storage
O
PC Motherboard
The Hardware/Software
Connection
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The hardware consists of the physical part of
the computer: CPU chips, RAM and ROM
chips
 The software is the program instructions used
by the CPU chip.
 The hardware function of the computer can
be changed by changing the software.
Embedded Systems
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An embedded computer is a special purpose
computer frequently used to control hardware
devices.
 Examples: microwave oven, automobile
engine control computer.
Examples of Embedded
Systems

Personal items such as personal digital assistants
(PDAs), mp3 players, mobile phones, videogame
consoles, digital cameras, DVD players, GPS
receivers, and printers.
 Many household appliances, such as microwave
ovens, washing machines and dishwashers, are
including embedded systems to provide flexibility,
efficiency and features.
 Advanced HVAC systems use networked thermostats
to more accurately and efficiently control temperature
that can change by time of day and season.
 Home automation uses wired- and wirelessnetworking that can be used to control lights, climate,
security, audio/visual, etc., all of which use
embedded devices for sensing and controlling.
Computers in Cars
All cars manufactured today contain at least one
computer. It is in charge of monitoring engine emissions
and adjusting the engine to keep emissions as low as
possible. The computer receives information from a
many different sensors, including:
The oxygen sensor
The air pressure sensor
The air temperature sensor
The engine temperature sensor
The throttle position sensor
The knock sensor
The oxygen sensor
Computers in Cars
Depending on how expensive your car is, there
can be all sorts of other computers. For example:
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There is probably a computer controlling the automatic
transmission
If the car has anti-lock brakes, there is a computer reading the
wheel speed and controlling the brakes
Many air bag systems have their own computers
A car with keyless entry or a security system has a computer for
these systems
Advanced climate control systems often have computers
Some cars now have motorized seats and mirrors that can
remember the settings for multiple drivers, and these contain
computers
Any radio or CD player with a digital display contains a computer
of its own
Cruise control systems use computers
Embedded Computers in Cars
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SPEECH TECHNOLOGY
LIGHTING SYSTEM
ELECTRONIC-MEMORY SEAT
ELECTRIC WINDOWS
MIRROR CONTROL
PREMIUM AUDIO SYSTEM
DOOR MODULE
CLIMATE CONTROL
VEHICLE-T0-ROADSIDE
COMMUNICATIONS
RAIN SENSOR
ONE-WAY DATA PAGER
DIGITAL RADIO
HIGH-INTENSITY DISCHARGE
LAMPS
NAVIGATION/GPS
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ALARM SYSTEMS
TRIP COMPUTER
HEAD-UP DISPLAY
ANALOG AND DIGITAL
INSTRUMENTATION
RIGHT-OF-CLUSTER DISPLAY
CRUISE CONTROL
INTERNET
INTEGRATED CELL PHONE
CENTRAL-BODY CONTROLLERS
CENTRAL LOCKING
REMOTE KEYLESS ENTRY
TRANSMISSON CONTROLLER
ENGINE CONTROLLER
IMMOBILIZATION
Embedded Computers
Typical Car Computer
The computer from a Ford Ranger
Future Cars
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Future car technology is now wide open. For instance, with
peak oil looming and future shortages of fossil fuels imminent
there has been much emphasis lately on cars that run on
alternative fuels.
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In the longer term, future car technology will most likely involve
cars that run on hydrogen, electricity, air, nitrogen, or even
nuclear power.
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In 1958 the first nuclear automobile was the Ford Nucleon. The
Ford Nucleon was a concept vehicle that was supposed to be
powered by a small nuclear reactor at the rear of the vehicle
fueled by radioactive material. No working prototypes were ever
built.
Summary
 Boolean
algebra is the short-hand
language used for logic
 Just
three operators AND, OR and
Negation
 Binary
is the language of computers
 Boolean
operators have electrical
analogues that are the template for
computers