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Basic Electronic Components An electronic component is any basic discrete device or physical entity in an electronic system used to affect electrons or their associated fields. Electronic components have two or more electrical terminals (or leads) aside from antennas which may only have one terminal. These leads connect to create an electronic circuit with a particular function (for example an amplifier, radio receiver, or oscillator).

Classification Components can be classified as passive, active, or electromechanic. 

Active components rely on a source of energy (usually from the DC circuit, which we have chosen to ignore) and usually can inject power into a circuit, though this is not part of the definition. Active components include amplifying components

such

as transistors,

triode vacuum

tubes (valves),

and tunnel

diodes. 

Passive components can't introduce net energy into the circuit. They also can't rely on a source of power, except for what is available from the (AC) circuit they are connected to. As a consequence they can't amplify (increase the power of a signal), although they may increase a voltage or current (such as is done by a transformer or resonant circuit). Passive components include two-terminal components such as resistors, capacitors, inductors, and transformers.



Electromechanical components can carry out electrical operations by using moving parts or by using electrical connections

Active Components An active device is any type of circuit component with the ability to electrically control electron flow (electricity controlling electricity). In order for a circuit to be properly called electronic, it must contain at least one active device.

Diodes

Conduct

electricity

easily

in

one

direction, among more specific behaviors.

Various types of Light-emitting diode

Transistors Transistors were considered the invention of the twentieth century that changed electronic circuits forever. A transistor is a semiconductor device used to amplify and switch electronic signals and electrical power.

Integrated circuits

An electronic circuit formed on a small piece of semiconducting material, performing the same function as a larger circuit made from discrete components.

Display technologies Current:



Filament lamp (indicator lamp)



Vacuum

fluorescent

display (VFD)

(preformed characters, 7 segment, starburst) 

Cathode ray tube (CRT) (dot matrix scan, scan

(e.g. radar),

arbitrary

radial

scan

(e.g. oscilloscope)) (monochrome & colour) 

LCD (preformed

characters,

dot

matrix)

(passive, TFT) (monochrome, colour) 

Neon (individual, 7 segment display)



LED (individual, 7 segment display, starburst display, dot matrix)

Vacuum tubes

A vacuum tube is based on current conduction through a vacuum.

Power sources Sources of electrical power: 

Battery –

acid-

or

alkali-based

power

supply 

Fuel cell – an electrochemical generator



Power supply – usually a main hook-up



Photo voltaic device – generates electricity from light



Thermo electric generator – generates electricity

from

temperature gradients 

Electrical generator – an electromechanical power

source

Passive Components Components incapable of controlling current by means of another electrical signal are called passive devices. Resistors, capacitors, inductors, transformers, and even diodes are all considered passive devices.

Resistors A resistor is electrical

component

a that

passive

two-terminal

implements

electrical

resistance as a circuit element. Resistors may be used to reduce current flow, and, at the same time, may act to lower voltage levels within circuits. Capacitors Capacitors store and release electrical charge. They are used for filtering power supply lines, tuning resonant circuits, and for blocking DC voltages while passing AC signals, among numerous other uses.

Magnetic (inductive) devices Electrical components that use magnetism in the storage

and

release

of

current: 

Inductor, coil, choke



Saturable Inductor



Transformer

electrical

charge

through



Magnetic amplifier (toroid)



Motor / Generator



Solenoid



Loudspeaker and microphone

Protection devices Passive components that protect circuits from excessive currents or voltages: 

Fuse – over-current protection, one time use



Circuit breaker – resettable fuse in the form of a mechanical switch

Antennas Antennas transmit or receive radio waves 

Elemental dipole



Yagi



Phased array



Loop antenna



Parabolic dish



Log-periodic dipole array



Biconical



Feedhorn

Electromechanical Terminals and connectors Devices to make electrical connection 

Terminal



Connector

Cable assemblies Cables with connectors or terminals at their ends 

Power cord



Test lead

Switches Components that can pass current ("closed") or break the flow of current ("open"): 

Switch – Manually operated switch.



Keypad – Array of pushbutton switches



Circuit breaker – Switch opened in response to excessive current: a resettable fuse

Mechanical accessories 

Enclosure (electrical)



Heat sink



Fan

APPLICATION OF ELECTRONICS IN AUTOMOBILES USE OF ELECTRONICS IN THE AUTOMOBILE Electronics are being used now in the automobile and probably will be used even more in the future. Some of the present and potential applications for electronics are 1. Electronic engine control for minimizing exhaust emissions and maximizing fuel economy 2. Instrumentation for measuring vehicle performance parameters and for diagnosis of on-board system malfunctions 3. Driveline control 4. Vehicle motion control 5. Safety and convenience 6. Entertainment/communication/navigation Historically, the first electronics (other than radio) were introduced into the commercial automobile during the late 1950s and early 1960s. However, these features were not well received by customers, so they were discontinued from production automobiles. Two major events occurred during the 1970s that started the trend toward the use of modern electronics in the automobile: (1) the introduction of government regulations for exhaust emissions and fuel economy, which required better control of the engine than was possible with the methods being used; and (2) the development of relatively low cost per function solid-state digital electronics that could be used for engine control and other applications. In order to give the evolution of electronics in automobiles a suitable perspective, it is helpful to consider the history of automotive electronics. Apart from auto radios, some turn signal models, and a few ignition systems, there was very little use of electronics in the automobile until the early 1970s. At about this time, government-mandated emission regulations, fuel economy, and safety requirements motivated the initial use of electronics. The dramatic performance improvements and relatively low cost of electronics have led to an explosive application of electronics in virtually every automotive subsystem. The relative cost/benefit of electronic subsystems in automobiles is largely affected by the production volume. (Some 15 to 16 million new cars and light trucks are sold in the United States each year.) Such a large

production volume significantly lowers the unit cost for any electronic system relative to aerospace volumes.

Systems of Automobile

The E N G I N E The engine in an automobile provides all the power for moving the automobile, for the hydraulic and pneumatic systems, and for the electrical system. A variety of engine types have been produced, but one class of engine is used most:

the internal combustion, piston-type, 4-stroke/cycle, gasoline-fueled, spark-ignited, liquid-cooled engine. Nevertheless, modern electronically controlled engines have much in common with this example configuration. For example, the vast majority of modern engines are 4-stroke/cycle, gasoline fueled, spark ignited, normally aspirated, and water cooled. The major components of the engine include the following:  Engine block 

Cylinder



Crankshaft



Pistons



Connecting rods



Camshaft



Cylinder head



Valves



Fuel control system



Ignition system



Exhaust system



Cooling system



Electrical system

Electronics play a direct role in all aspects of controlling engine operation, including the fuel and air flow control, ignition, exhaust and evaporative emission systems, and diagnostic and maintenance operations as well as many other secondary functions. In the earliest days of government regulation, electronic controls were applied to existing engine designs. However, as electronic technology evolved, the engine mechanical configuration was influenced (at least indirectly) by the electronic controls that were intended to be applied.

IGNITION SYSTEM To produce power, the gasoline engine must not only have a correct mixture of fuel and air, but also some means of initiating combustion of the mixture. Essentially the only practical means is with an electric spark produced across the

gap between a pair of electrodes of a spark plug. The electric arc or spark provides sufficient energy to cause combustion. This phenomenon is called ignition. Once a stable combustion has been initiated, there is no further need for the spark during any engine cycle. Typically, the spark must persist for a period of about a millisecond (one thousandth of a second). The ignition system itself consists of several components: the spark plug, one or more pulse transformers (typically called coils), timing control circuitry, and distribution apparatus that supplies the high-voltage pulse to the correct cylinder.

GOLDEN GATE COLLEGES MECHANICANICAL ENGINEERING DEPARTMENT

BASIC ELECTRONICS IN

AUTOMOTIVE

ENGR. NESTOR VISAYA

BACAL, DAN RAY BADILLO, NORMEL