34080945 automotive electronics

Upload: usamedemir

Post on 09-Apr-2018

222 views

Category:

Documents


0 download

TRANSCRIPT

  • 8/8/2019 34080945 Automotive Electronics

    1/29

    1

    CONTENTSPRINCIPLES electrical / electromagnetic

    Atomic structure ................................................ .................................................. ................................... Electri

    city ............................................... 5 .................................................. .................................... 7 voltage, voltage or potential difference .......................................... .................................................. .... Amperage .............................................. 8 .................................................. .............................. Electrical Resistance ............................................... 10 .................................................. ................................. Association of resistance .............................................. 12 .................................................. ........................ OHM Act .............................................. 13 .................................................. ............................................ Magnetism ................................................ 15 .........

    ......................................... ............................................ Electromagnetism ................................................ 16 ....

    .............................................. .................................Induced electromotive force .............................................. 20 .................................................. .................. Self-induced electromotive force .............................................. 21 .................................................. ............ Inductive pulse generator 24 ............................................. .................................................. .............. 25 Impulse Hall ............................................. .................................................. ...................... Piezoelectric Sensor ............................................... 27 .................................................. ............................... Piezoresistive sensor ............................................... 30

    .................................................. ............................. Electromagnetic relay ............................................... 31 .................................................. ............................. Relay Types .............................................. 33 .................................................. ........................................... 35

    2

    The multimeter Description ............................................... .................................................. ............................................. Types of polymers ............................................... .................................................. ...............................

    . Analog multimeters ................................................ .................................................. ............................ ..........

    ..................................... Conventional digital multimeter ..........

    ........................................ ............... .......................

    ........................ Advanced digital multimeter ...........................

    ....................... ...................... Precautions .....................

    ......................... measurement ..........................................

    ........ .................... Ohmmeter measurements polymers ...................

    ........................... .................................................. .

    ...................................... Voltmeter ...............................

    .................. .................................................. ..........

    ...................... Ammeter ................................................................................................... ............................

    Reading Exercises ............................................... .................................................. ............................... 48 49 50 51 41 42 43 44 45 47

  • 8/8/2019 34080945 Automotive Electronics

    2/29

    ELECTRONIC PRINCIPLES ............................................. resistors orresistances .................................................. ........................... ................................................ Fixed resistors .................................................. ................................... ................................................ Variable resistors .................................................. ........................... Special r

    esistance ................................................ .................................................. ......................... Semiconductor diode ................................................ .................................................. ............................ Zener Diode .................................................................. .................................................. ........................ Led LED ............................................... .................................................. .............................. Photodiode ................................................. .................................................. ............................................ Transistor ................................................. .................................................. ............................................ 57 61 63 65 71 74 76 78 80

    3

    The oscilloscope The oscilloscope ................................................................................................ ........................................ Oscilloscope Types ................................................................................................. .............................Controls ................................................ .................................................. ......................................... The display ................................................ .................................................. ............................................. The probes................................................ .................................................. ............................................. Onda Concepts

    .............................................. signal .................................................. ............................................ 104 97 9899,100,101

    Most common forms of wave ............................................. .................................................. ...... Period ................................................ 105 ........................................................................................ Frequency ................................................. .................................................. ................................ Size ................................................. .................................................. .................................. Pulse ................................................. .................................................. ........................................ 108 110115 123

    Automotive Oscilloscopes ............................................... .................................................. .............. Signal injection .............................................. 124 .................................................. ................................... Lambda Signal ............................................... 126 .................................................. .......................................... 127 idle actuator controlsignal two windings .......................................... ............................................ 128

    4

    Atomic Structure The matter consists of infinitesimally small particles called molecules, these

  • 8/8/2019 34080945 Automotive Electronics

    3/29

    in turn are divided into atoms.

    -

    -

    Atoms are made up of protons and neutrons in the nucleus and electrons moving

    elliptical orbits forming the crust. A proton is positively charged (+) and negative electric electron (-). Metals have the property that the atoms that form tend to lose one or more electrons in its last layer, llamndoseles free electrons, which create these holes may be occupied by other free electrons.

    -

    5

    Atomic Structure As the electrons rotate in the orbit farthest from the nucleus are less boundto the atom, it happens sometimes that some of them escape, perhaps by the shock

    of a free electron approaches them at high speed. Then outweighs the positive charge exists in the nucleus, the atom has become a positive ion. Conversely, the envelope can capture additional electrons free electrons. Then outweighs thenegative charge of the electron shell, the atom has become a negative ion.

    -

    -

    -

    -

    + + + +

    -

    -

    + + + +

    + + + +

    -

    No e-> p + No6

    ELECTRICALLY NEUTRAL BODY

    BODY POSITIVE CHARGE

    BODY negatively charged

    No e-= p + No

    No e-

  • 8/8/2019 34080945 Automotive Electronics

    4/29

    VOLTAGE, VOLTAGE OR POTENTIAL DIFFERENCE It is the electric force with which the electrons are pushed through a conductor. The tension appears in the electrical circuits in two ways: induced electromotive force (emf): The tension that generates a power source, as can be a battery, generator, etc ... Voltage drop: The voltage that is lost in the receivers.

    0

    P

    V Comparing the term with a hydraulic circuit, the voltage would correspond to the pressure applied to a fluid so that it travels through a pipe.

    8

    TENSION,DIFFERENCE OF POTENTIAL OR VOLTAGE The unit of measurement is the Volt. The volt (V) is multiple the megavolt (

    MV) and KV (KV) and as submultiples MV (mV) and the microvolt (microvolts).

    1 MV = 1,000,000 V

    1 V = 1.000 mV

    1 kV = 1,000 V

    1 = 0.000001 V

    The device can measure the stress is called voltmeter is connected in shunt orin parallel with the circuit whose voltage you want to know. Put another way, the terminals of the voltmeter must join the two points between which a dap or te

    nsion to be measured. 9

    CURRENT STRENGTH INTENSITY is called, the number of electrons circulating in a consumer, when applied to this tension, in the unity of time (seconds).

    I

    The intensity of electric current in the hydraulic circuit corresponding to the amount of water passing through the turbine (producing a work) in unit time, ie the flow.

    The amount of fluid flowing through the canal, will be equivalent to the amount of current flow through a resistance or consumer when you apply a voltage across it.

    10

    CURRENT STRENGTH The unit of measurement is the Ampere. The ampere (A) is submultiples the milliamp (mA) and the microampere (uA).

    1 A = 1000 mA

    1 mA = 0.001 A

    1 A = 1,000,000 uA

  • 8/8/2019 34080945 Automotive Electronics

    5/29

    1 uA = 0.000001 V

    The device can measure the intensity of electric current is called an ammeterconnected in series circuit, ie so that the electric current to pass in its entirety by him. The circuit must be working. 11

    ELECTRICAL RESISTANCE

    flame resistance is the opposition that has a body to the passage of electriccurrent, ie the difficulty encountered by the electrons to move.

    The unit of measurement is the ohm (). The instrument used to measure resistance is the Ohmmeter. Connection: Parallel when you go to take measurements of resistance, must be isolated and disconnected from the mains circuit.

    As a multiple of Ohm is used kilohms (K) and the megohm (M) and is used submultiple milliohms (m) and micromhos ().

    1 M = 1,000,000 ohms = 1.000 ohms 1 kOhm

    1 1 = 1.000 m = 0.000001 12

    ASSOCIATION OF RESISTANCE (I) ASSOCIATION SERIES

    R1

    R2

    R3

    Rt = R1 + R2 + R3 A series circuit is formed by various components mounted in cascade, ie the ou

    tput of a component connected to the input of another, so for all components. The intensity of current through a component, is the same value as that of others, since there is no referral to another part of the circuit. The total resistance of a series circuit is equal to the sum of the partial resistance of its components.

    13

    ASSOCIATION OF RESISTANCE (II) ASSOCIATION IN PARALLEL R1 R2 R3

    1/Rt = 1/r2 + 1/R1 + 1/R3

    Rt =

    X R1 R2 R1 + R2

    A parallel circuit is when you connect two or more components, with two commonpoints, ie in a terminal and go the other will go the other end of each component. The voltage of this type of assembly has the same value in all branches. The current supplied by the generator, shall be allocated in each of the branchesof the assembly. The total resistance that the assembly will always offer less than the resistance is smaller than in the circuit.

    14

    OHM'S LAW"The intensity of electric current in a circuit obtained is directly proportiona

  • 8/8/2019 34080945 Automotive Electronics

    6/29

  • 8/8/2019 34080945 Automotive Electronics

    7/29

    Other bodies such as bismuth, have the property to reject the lines of force,ie they are more easily passing through the air through the body, producing a distortion of the field. These bodies are called diamagnetic.

    19

    ELECTROMAGNETIC When a straight wire through which an electric current is placed near a compass, it deviates from its position, "seeking" the perpendicular to the driver. Increasing the current intensity, the compass takes increasingly more perpendicularposition. This effect is due to electric current creates a magnetic field around it that are analogous to magnets and whose intensity is proportional to theamount of current flowing through the electrical circuit.

    20

    Induced electromotive force Faraday showed that when a driver crosses the lines of force produced by a mag

    netic field is generated in him an induced electromotive force (feminist), whichis directly proportional to the flux cut, and inversely proportional to the time taken to do so.

    That is:

    (Difference Flow) (Time Difference)

    The same effects are observed if instead of bringing in or out of the magnet to the coil, it is this that moves toward or away from the magnet. Changing thepolarity of the magnet, the direction of current in the coil is opposite to that obtained previously.

    21

    Induced electromotive force Consider a circuit consisting of two solenoids, the first, which we call primary coil, powered by a battery and the second, which we call secondary coil and acircuit is closed by an ammeter, as shown in Fig.

    The closing of the switch, the current flowing through the primary coil and the expansion flow in short the secondary winding and induces in it an emf causingan electrical current. Once the flow is fully expanded, ie the maximum value, no change in the secondary flow, therefore the induced current in this is zero.

    22

    Induced electromotive force When the switch opens the magnetic field disappears, resulting in the emergence of a new fem, and causing an electrical current in the opposite direction to the previous. Once the flow has completely disappeared, there is no variation inthe secondary flow, therefore the current is zero.

    Whenever there is a change in flux that cuts the turns of a coil, it induces anemf in this induced, giving rise to an electric current if the circuit is closed. 23

    Self-induced electromotive FORCE

    The inductance is produced in any coil that has a sharp cutoff in the flow ofcurrent. This effect is sometimes the product of interference and disturbances i

  • 8/8/2019 34080945 Automotive Electronics

    8/29

    n electronic circuits.

    24

    Inductive Pulser It consists of a ring gear with an absence of two teeth, called phonic wheel,coupled to the periphery of the wheel or pulley, and a magnetic sensor placed in

    front of it, formed by a coil wrapped around a permanent magnet.

    25

    Inductive Pulser

    26

    Hall Pulser The operation of this generator is based on the physical phenomenon known as the Hall effect.

    A semiconductor is a current path between points A and B, if you apply a magnetic field NS, perpendicular to the semiconductor, generates a small voltage (Hall voltage) between points E and F due to the deviation of the lines current by the magnetic field, when these two conditions occur simultaneously.

    27

    Integrated Hall The Hall integrated circuit acts as a switch, transferring mass to the neutralterminal (or) as often as directed by the semiconductor Hall. For the terminal (or) the control module sends a reference voltage, which the conduction stateof the power stage integrated Hall,fall almost to zero or not.(+) Voltage stabilizer power stage

    Semiconductor Hall

    Amplifier

    Signal Converter

    (O) (-)

    Temperature Compensation

    28

    Hall Sensor applicationPhase Sensor Camshaft Housing

    Corona generating

    29

    Piezoelectric sensors It is a material (Pyrex, quartz ,...) that is sensitive to pressure variations. No pressure sensor loads, have a uniform distribution (1). By acting pressure, spatially moving loads (2), producing an electrical voltage. The greater the pressure, the more intensely they separate the charges. The tension increases.

    In the electronic circuit intensifies the tension built and transmitted as a signal to the control unit. The magnitude of stress is thus a direct measure ofthe pressure prevailing in the system to be controlled.

  • 8/8/2019 34080945 Automotive Electronics

    9/29

    30

    Piezoresistive SENSOR The sensitive element consists of a Wheatstone bridge made of semiconductor resistors screenprinted on a very thin aluminum diaphragm. On one side of the diaphragm acts a reference pressure, while on the other hand, does the pressure to b

    e measured.

    Diaphragm

    Bridge resistance

    Support

    Output Voltage

    Supply voltage

    The control unit maintains a 5 volt power to the sensor. A variation of pressure causes the diaphragm to bow ceramic sensor by varying the value of the resistance of the bridge and also by varying the value of output voltage.

    31

    32

    Electromagnetic RelayA large number of existing power plants are sent in an automobile component called electromagnetic relays or contactors. The relay allows you to send, through alow current circuit (drive circuit) circuit that works with higher current (power circuit). The electromagnetic coil is inserted into the field circuit with a

    very weak consumption in the order of milliamps: current passing through it creates a magnetic field such that a shift from the armor from the rest position tothe position. The truss command acts on the opening and closing of the contacts,allowing current flow to consumers concerned.Driving coil

    30

    Consumer

    A return spring returns the armature to the rest position when the excitation current disappears. 33

    Need RelaysIf an installation that consumes a lot of govern only with the help of a simpleswitch, because their internal contacts are usually not dimensioned to withstanda high current intensity, this would deteriorate rapidly with warming serious consequence would be subject to and leading to significant voltage drops in the installation.Lights Switch

    Battery

    Lights Switch

    Battery

    Relay

  • 8/8/2019 34080945 Automotive Electronics

    10/29

    To avoid this, the relays are used, so that the current flows through the shortest route from the battery through the relay to the headlights. Since the switchon the board until the relay driver is sufficient command of only 0.75 mm2, since consumption is about 150 mA. 34

    Relay Types

    Simple relay of work: In these types of relays, the relay will put together thepower supply to consumers, shareholders via a switch or other control device.

    Type B:30 or March 1987 or May 1986 or January 1986 or January 1985 or 2

    87 or May 1985 or 2

    30 to 3

    Type:30 to 3: Input power. 87 or 5: Power output. 85 or 2: Negative excitement. 86 or

    1: Positive excitement.

    87 or 5

    30 to 3

    85 or 2

    86 or 1

    35

    Working double relay

    In this type of relay current output is produced by two terminals to be excitedonce the relay.

    Type B:87b or May 1930 or March 1987 or May 1986 or January 1986 or January 1985 or 2

    87 or May 1985 or 2

    30 to 3

    87b or 5

    Type:30 to 3: Input power. 87 or 5: Power output. 87b or 5: Power output. 85 or 2: Negative excitement. 86 or 1: Positive excitement.

    87 or 5

    87b or 5

    30 to 3

    85 or 2

    86 or 1

    36

  • 8/8/2019 34080945 Automotive Electronics

    11/29

    Switching RelayActs alternately on two control circuits or power. One is controlled when the contact elements are in working position, while the other one is when the contactelements are in the position.

    Type B:87th or April 1930 or March 1987 or May 1986 or January 1986 or January 1985 or

    2

    87 or May 1985 or February 87th or March or April 1930

    Type:30 to 3: Input power. 87th or 4: Power output at rest. 87 or 5: Power output enabled. 85 or 2: Negative excitement. 86 or 1: Positive excitement.

    87 or 5

    Or April 87th

    30 to 3

    85 or 2

    86 or 1

    37

    Special RelaysThere are a number of special relays for very specific uses, or available to specific terminals.In this small study we present the relays with resistance or diode extinction and blocking diode.

    Resistance relay

    Relay with diode extinction

    Diode Relay with extinction and blocking

    The purpose of the resistance and the diode is to protect the relay control element of potential self-induced currents generated in the excitation coil itself,which could lead to the deterioration of this. 38

    Miscellaneous Applications of RelaysRelay stadia: Double injection relay

    - Coil

    Departures

    50 87 1 TDStart

    Contact

    87b 30

    15 31

    Mass 15 8 12 14 7 4 5 6 13 11 3 2 10 9 1

    Direct positive

  • 8/8/2019 34080945 Automotive Electronics

    12/29

    39

    40

    DESCRIPTION Polymer is called, the device capable of performing multiple (poly) measuremen

    ts (meters), also known by the name of multimeter or test. Within the instrument can distinguish three different measures with which we will perform the mostcommon readings: VOLTMETER AMMETER Ohm Resistance () Voltage (V) DC and AC Current (A) in DC and AC41

    Types of polymersClassification of polymers in terms of its technology. ANALOG

    Polymer DIGITAL Conventional Automotive Specific

    42

    Polymer ANALOG The analog multimeters, today, are no longer used because of its lower resolution and more complex reading. They are sensitive to reverse polarity, and their reading is affected by vibration. On the other hand, are more reliable whenmeasurements that vary rapidly in time.43

    CONVENTIONAL DIGITAL Polymer The indication is done through measurement of digits displayed on a liquid crystal display. The measurement is more accurate, but turn slower. Withstand higher intensities are more accurate when the measurement is carried out under di

    fficult working conditions, and vibrations. Provides protection elements and circuits that make it locks if you have selected a wrong scale. If the polarityis reversed probes, displayed the sign (-) negative result.44

    CONVENTIONAL DIGITAL PolymerDisplay On / Off Switch VCD: TensionDC

    ADC: IntensityDC

    VAC: TensionAC

    AAC: IntensityAC

    OHM Range Selector: COM Resistance Control: input socketfor all measures

    mA input socketfor measurements up to 0.2 A. Fuses

    10A: input socketfor measures to 10A.Sin fuse protection

  • 8/8/2019 34080945 Automotive Electronics

    13/29

    V-: input socketmeasures voltage / resistance

    45

    ADVANCED DIGITAL Polymer They are geared almost exclusively to the automotive world. Besides all the

    measurements that can be performed with a conventional multimeter with advancedmuch wider field, for example, FREQUENCY (Hz) Temperature ( C) RPM (rpm) Duty cycle (% DWELL)46

    MEASUREMENT PRECAUTIONS When we measure resistance, resistance to ensure that the measure is not undertension and disconnected from any facility. Start from the highest level andgo down to get an accurate measurement. We should not touch the probes with your fingers, because the internal resistance of the body can vary the measurement. When we measure voltage, first we'll make sure this type, AC or DC. Start the measurement from the highest level and go down to get an accurate measurement.

    When measuring current, we must take into account that the fuse protection isonly valid up to 0.2 Amps for higher intensities the other terminal is generally used without any protection. 47

    Polymer Ohm MeasurementApplication: Measure the resistance and continuity of a circuit or component andthe isolation of the same with respect to ground.

    CONTROL OF RESISTANCE48

    Polymer WITH VOLTMETER MEASUREMENTSApplication: The measurement is done in parallel. Measure the voltage coming toan item, as well as the voltage drop that has an electrical circuit.

    V

    VOLTAGE CONTROL OF FALL

    49

    Polymer MEASURES WITH AMMETERApplication: The measurement is done in series. Measure the intensity of currentdrawn by a circuit.

    A

    CONSUMER CONTROL50

    READING EXERCISE (I) Ohmmeter Set the selector to obtain the most accurate reading. 4K7

    51

    READING EXERCISE (II) VOLTMETER

    Set the selector to obtain the most accurate reading.

    52

  • 8/8/2019 34080945 Automotive Electronics

    14/29

    READING EXERCISE (III) AMMETER Set the selector to obtain the most accurate reading. 4K7

    53

    READING EXERCISE (IV) CONTROL OF DIODES

    Set the selector to perform the test correctly.

    54

    READING EXERCISE (IV) CONTROL OF DIODES Set the selector to perform the test correctly.

    55

    +

    56

    Resistors ResistorsResistor is called the component made especially for offering a specific electrical resistance. On the contrary, the resistance is the ohmic value resistor. However, in the colloquial language and practice the word resistance is used to designate the resistor. For this reason, we used the nomenclature of resistance. Ina resistor are three important characteristics that define their working conditions and use: Resistance. Tolerance. Rated. The classification of the heating is carried out according to different criteria. We agree with the use of ourfield of work, classify them according to their ability to modify its ohmic value in fixed and variable. 57

    Resistance Characteristics

    Resistance:Is the ohmic value of a resistor (resistance) commercial and not generally exactly the right choice. So we must distinguish the concepts of nominal value, whichis provided by the manufacturer and the actual value of the resistor.

    Tolerance:It's the difference between the value of real and nominal resistance. This can be defined as the range between the maximum and minimum resistance. Within these,any resistance value is considered suitable for use. Not all the resistors haveto work under the same conditions or on the same circuits. So there are two types of tolerances: Standard tolerances: 20%, 10% 5%. Precision Tolerances: 2% 1%, 0.5% 0.1%.

    Rated Power:It indicates the ability to dissipate heat is directly related to its size, thelarger, more powerful. The most common power commercial resistors: 1 / 4 W, 1 /3 W, 1 / 2 W, 1 W, 2 W and 4 W. Wound resistors are an exception, since their maximum powers are much higher: 100 W, 250 W, 400 W and 500 W.

    58

    Color CodeObserving a commercial resistance, in most cases it is observed that the ohmic value of resistance, such as manufacturing tolerance are indicated by a color code, which is read from left to right.

    3rd 4th Gaza Strip

    1st 2nd Gaza Strip

  • 8/8/2019 34080945 Automotive Electronics

    15/29

    The first step in determining the resistance value is read your tolerance, which is indicated by the last group. Later, we see the color of the first stripon the left that indicates the value of the first significant figure, the secondsegment, second and third significant figure, the number of zeros that are after the first two digits. 59

    Color Code ChartNOTE FRINGEBlack Brown Red Orange Yellow Green Blue Violet Gray White Gold Silver No Color

    A 1 Cifra0 1 2 3 4 5 6 7 8 9 -

    Figure B 2nd0 1 2 3 4 5 6 7 8 9 -

    C Multiplierx1 x 10 x 100 x 1000 x 10 000 x 100 000 x 1,000,000 x 0.1 x 0.01 -

    D Tolerance 1% 2% 5% 10% -

    60

    Fixed ResistorsThey are manufactured with a fixed ohmic value, determined and standard, which is indicated, as already seen, in the body of resistance. According to their manufacture, can be bonded resistance differences, carbon film resistors, metal filmresistors and wirewound resistors. All of them have some peculiarities that make its operation to be used in some circuitsPainting ceramic support layer

    Winding Resistance

    Terminal

    Carbon Resin

    Coal resin Resistance

    Resistance of chipboard

    61

    Example of Application in the AutomobileThere are variables resistance applications in the car, not only are present internally in the various control units, but also form part of certain electrical circuit.Circuit fan speed selector carrier.Joint strength and motor

    Battery Power

    MO TThe selection of the various links of resistance, makes the motor supply voltagevaries, getting to vary the speed of it.

    Selector

  • 8/8/2019 34080945 Automotive Electronics

    16/29

    62

    Variable ResistorsThese types of resistors are called potentiometers, be possible to modify the ohmic value through a mobile device called a cursor. These values range from zeroto a maximum, depending on the characteristics of the resistive material used and the constructive characteristics.

    Fixed Value

    Schematic representation

    Variable value

    Variable value

    It is often used as a rheostat, producing variable voltage drops or voltage divider, with the output voltage proportional to the resistance cursor that represents your position. 63

    Example of Application in the AutomobileThrottle position sensor. Fin flow.Throttle position sensor

    Signal

    +

    All these sensors are potentiometers try reporting to their respective control units through a variable voltage depending on its position.

    64

    Special Resistance

    Resistive change their characteristics with the variation of certain physical quantities such as temperature, light, stress, etc.

    Light-sensitive resistors:Commonly known as LDR (light dependent resistor), light-dependent resistance. They are constructed of materials that become drivers, the light energy influenceon them (cadmium sulfide). Thus, the higher the light energy, the lower the ohmic value of resistance.

    LDR resistors have a value of several megohms (10 M). When exposed to light, its resistance drops to a few ohms (75-300 ). 65

    Temperature-sensitive resistorsThere are two types of temperature-sensitive resistors: the negative temperaturecoefficient (NTC) and positive temperature coefficient (PTC). NTC resistors arecharacterized by varying their ohmic value inversely with temperature. Thus, higher temperatures have less resistance. PTC resistors are characterized by varying their ohmic value in direct proportion to temperature. Thus, at a lower temperature with more resistance.

    NTC PTC

    Several types of thermistor

    66

    Example of Application in the AutomobileThe main application of temperature-sensitive resistance is like water temperatu

  • 8/8/2019 34080945 Automotive Electronics

    17/29

    re sensors, fuel, air, etc. They are used in any type of circuit as air conditioning, injection, suspension, etc. PTC is also used as resistance heating lambdaprobe, butterfly box, intake manifold, etc.Temperature Sensor motor. Air temperature sensor throttle position sensor

    PTC heating

    67

    Voltage sensitive resistorsThe abbreviation of the resistance is sensitive to tension VDR (voltage dependent resistor). Grams are usually constructed of silicon carbide, shaped in small cylinders or discs. These elements are nonlinear resistors whose ohmic value decreases with increasing applied voltage terminal. Elements are commonly used as voltage stabilizers and particularly to protect mobile contacts such as switches,relays, etc..

    Several types of varistors or VDRs

    68

    Magnetoresistive resistorsThis is a magneto-resistive resistor whose characteristic is ohmic value that varies depending on the magnetic field lines (magnetic flux) that passes through.o o

    In the car this type of resistance does not act alone but is integrated into a sensor, which in turn includes an electronic sensor. An example of this is used a

    s a magnetoresistive sensor system sensor wheel ABS braking system. Implanting apulse generating wheel, equipped with a hint of exploration. 69

    Magnetoresistive resistorsIn the immediate vicinity of magnetic areas, magnetic field lines run verticallyon the trail of exploration. According to its polarity, are directed toward oneor the other side of the track. Under scanning the track passes very close to the sensor, magnetic field lines also cross the sensor and affect its strength.

    An electronic circuit, integrated in the sensor, converts the resistance changesat two different levels of current. That means that the current drops to increase the resistance of the sensing element under the guidance are magnetic field lines that cross. The current intensity increases as resistance is reduced by a reversal of the direction of the field lines and vice versa. 70

    Semiconductor DiodeThe diode is an electronic component made of semiconductor materials (germaniumor silicon), whose peculiarity is that only lets the electric current in one direction. Its symbol is the one, and comprises a positive terminal and a negativeanode called called cathode. Outwardly have a band to indicate the direction ofpassage.Anode Cathode Anode Cathode

    Yes No

    If

    In a hydraulic metaphor, the diode behaves like a valve.

  • 8/8/2019 34080945 Automotive Electronics

    18/29

    71

    If we connect the positive terminal of a battery to the negative anode and cathode of a diode, the diode is said to have been biased. Increasing the bias, increases the current passing through the diode, but if this polarization becomes excessive, it breaks the crystal structure of the diode being disabled.

    To set the current step is necessary to establish a minimum voltage of about 0.6to 0.75 V, called the threshold voltage or barrier.

    If we connect the positive terminal of the battery and the negative cathode to the anode of the diode, it is said that the diode is reverse biased. Increasing the reverse bias that can drill and destroy.If a diode is subjected to reverse voltage, it leaves a small circular current,which is called leakage current is negligible

    72

    Application of Diodes

    Logically within the various control units is unipresente, but the diode is alsoused when you want the current to flow in only one direction in part of the installation or especially as a bridge rectifier in the alternator rectifier circuit load.

    Electronic Regulator

    Rotor

    Stator

    Bridge Rectifier

    Alternator

    73

    Zener diodeLike a normal diode, current will pass when it is directly polarized. But when it is reverse biased, the diode conducts, letting all the reverse current to reach a certain tension, called the Zener voltage and the voltage kept constant.Anode Cathode Anode Cathode

    6.8 VIf only from Zener voltage VZ Only from VZ If

    Faced with a biased, the zener diode functions as a normal diode.

    74

    By connecting the zener diode reverse biased, the diode behaves like a normal diode, as long as the applied voltage is less than the zener voltage.

    V: 4 V

    Vz: 6.8 V

    If we maintain the reverse bias zener and increase the voltage to exceed the val

    ue of the Zener voltage, we observed that the diode allows current flow, tryingto get across it there is a voltage difference equal to the Zener voltage.

  • 8/8/2019 34080945 Automotive Electronics

    19/29

    V: 8 V

    Vz: 6.8 V

    Zener diodes are used in various electronic circuits such as limiters and voltage stabilizers. 75

    Led LEDThese are diodes that emit light when current flow, there are of different sizeand color, we must be careful to respect the polarity because if you place willnot look backwards as a diode that is, to distinguish the polarity of the pin islonger than the other to tell which is positive. The LED (Light Emisted Diode)for smooth operation must be connected between 1.7 to 2.5 V, and he has to travel a current of about 10 mA. If you are subjected to more tension ends up meltingand if set to a lower voltage that emits light is poor. To connect to a sourceof 12 V is placed in series resistance of about 1 kOhm.12 V Anode Cathode

    +

    No Yes + lights

    1 kOhm

    Cathode identification Notch

    76

    There are models of two-color LEDs, LED differentiating bi-pin and two bi-colorLED of three pins. In the two-pin bi-color LEDs, depending on the polarity thatexists in his whiskers will turn red or green.

    Green

    Red

    In the three-pin LED color depends on the diode for the flow of electrical current, if current flows through both at the same time appears orange as a mixture of both. We actually have three colors.K

    Green

    Red

    K

    77

    PhotodiodeThe photodiode is a semiconductor designed so that the light that strikes it allows an electric current in the external circuit. The photodiode is an optoelectronic detector or photodetector, which allows switching and dimming the electriccurrent in an external circuit in response to a variable light intensity. The photodiode develops a function opposed to an LED and photodiode that converts optical energy into electrical energy.Anode Cathode

    If the light intensity depends

  • 8/8/2019 34080945 Automotive Electronics

    20/29

    Faced with a bias, the photodiode acts as if it were a normal semiconductor diode.

    78

    Faced with a reverse bias, the photodiode allows passage of current proportionalto the intensity of light it receives. If the light intensity is small, the cur

    rent step is less, if instead the light intensity is large, the current step islarger.

    The photodiode is used in the automobile and light sensor control unit for the air conditioning. The sensor reports the level of incidence of sunlight in the vehicle, enhancing the climate under the impact of these on the vehicle. 79

    TransistorYou can say that in general the transistors are electronic devices with two junctions and three terminals, whose main function is the amplification, ie the power to control a high current through the variation of a much weaker power. According to the succession of the crystals that form the transistors, we can find two

    different types of transistors: NPN and PNP type. Both a type and the other consists of three terminals called base, collector and emitter.

    PNP Transistor typeCollector Emitter Collector Emitter

    P

    N

    P

    Base

    Base

    80

    NPN TransistorCollector Emitter Collector Emitter

    N

    P

    N

    Base

    Base

    Using the transistor:The transistor can work in the following conditions: Driving States Court TurnsTo understand the different behavior of the transistor we will support a hydraulic analogy. 81 Saturation

    Working principleIn the hydraulic analogy of water flow through the duct EC (emitter-collector) d

    epends on the positioning of the trap, which in turn is driven by the flow EB (emitter-base), then the flow between the duct EC (IC) is proportional to the conduit between EB (IB).

  • 8/8/2019 34080945 Automotive Electronics

    21/29

    E

    IC

    C

    IB

    E

    ++

    C

    BFor current flowing through the base pressure in the Issuer must have more potential (more pressure) than in the Base. The higher the potential (pressure) in E

    greater the base current and the greater the current through CE. 82

    B

    Working principleIf the potential (pressure) of the base is bigger than the Issuer in the hatch would be closed preventing the passage of CHD. We note that has a small increasein current through the base produces a large increase in current through CE.

    E

    +

    C

    +B

    83

    Transistor operationThe Issuer is where the arrow and he runs all the current IE = IC + IB.

    PNP Type:TransmitterIE IC

    Collector Emitter

    P

    N

    Collect P r Base

    IB

    Base

    NPN:Transmitter

  • 8/8/2019 34080945 Automotive Electronics

    22/29

    IE IC

    Collector Emitter

    N

    P

    Base 84 r N Collect

    IB

    Base

    Transistor operationWhen the transistor operates in saturation, its operation is much like a relay.When pressing the button, it creates a base current, limited by the resistance,which causes the drive transistor and turn on the lamp.

    85

    86

    PNP Type

    87

    88

    NPN Type

    89

    When the transistor operates in active leadership says it is working in amplifier, ie it determines the current between the emitter and collector, regulating the flow of base:

    IC = * IBPNP Type:

    IC: Current collector

    IB: Current

    ase. B: gain of the transistor.

    90

    NPN Type

    91

    Darlington TransistorThe transistor "Darlington" in its appearance, not much different from a normaltransistor since it has three electrodes: emitter, collector and

    ase. Inside has two transistors mounted in cascade, ie the output of the first transistor is the input of the second transistor, with their respective

    ias resistors.The switch sets the current through the

    ase of T21, creating a collector current that polarizes T22

    ase and causing the main current flow

    etween collector an

    d emitter of darlington.

    The advantage of this transistor is due to its high gain, since the

    ase current

  • 8/8/2019 34080945 Automotive Electronics

    23/29

    needed to drive the emitter-collector circuit, is much smaller than in the caseof assem

    ly of a single transistor. In this way, applies to virtually all the emitter current to the load through the collector. 92

    Example Application of TransistorsElectronic RegulatorThe exciting current is controlled

    y the transistor (T3) that closes or opens t

    he circuit or canceling letting this current. The regulated voltage control is achieved through the transistor (T1), the zener diode (Dz) and a voltage dividerformed

    y resistors (R1) and (Rz). While the generator stopped, closing the switch (I), the terminal voltage of the alternator will

    e the

    attery, and the voltage at point "B" with respect to point "A" will

    e lower than the zener (Dz) , there

    eing no driver in it, and therefore not included in the transistor (T1), this situation gives rise to a current set of sign (+) at the

    ase of the transistor (T2), allowing the passage of current through thereof. The current flowing through the transistor (T2) is the

    ase current of the transistor (T3), so this also leads.

    93

    Example Application of TransistorsTouch circuit

    reaker15

    and c

    and

    c and

    c 30 86 85 87

    87th

    31

    94

    95

    THE OSCILLOSCOPE A Polymer either analog or digital, reports only the mean values or effective,as you work your way precludes further point to point the signal is applied.

    The oscilloscope can display the forms and variations over time of signals applied to its inputs.

    96

    THE OSCILLOSCOPE The oscilloscope is a measuring instrument on a screen that presents a graphicimage of an electrical signal. This image shows how the signal changes as timegoes on The image is drawn on a screen that plays a coordinate axis (voltage /time). This allows to determine the time and voltage values of a signal, so as frequency, pulse rates, duty cycles (DWELL, RCO or cicle dusty, etc.).97

    TYPES OF OSCILLOSCOPEOSCILLOSCOPE ANALOG: Works

    y direct application of the voltage is measured at a

    n electron

    eam that runs the screen

    Oscilloscope La

  • 8/8/2019 34080945 Automotive Electronics

    24/29

    DIGITAL OSCILLOSCOPE: Take samples of the signal at discrete intervals of time,stored in its memory as points of the waveform. Using this information the oscilloscope waveform reconstructed on the screen.98 Digital Oscilloscope

    CONTROLS

    A series of controls on the front panel to adjust the image size, monitor themovement and measure its value

    VERTICAL HORIZONTAL CONTROL CONTROL

    Time Base. They act on the sweep speed of the spot on the screen.

    Adjust the level of tension, ie the input sensitivity.

    Attenuate or amplify the signal and change the image size so that it can adapt to the screen and is plainly visi

    le.99

    DISPLAY The screen or display area is a liquid crystal (LCD) that forms a matrix of hundreds of dots (pixels) which, when properly polarized change their transparency, the contrast

    etween opaque and transparent are the track Waveform Display Grid

    Zero Online Reference

    Tension Division

    Time per Division

    100

    THE PROBES A pro

    e is a pro

    e of high quality, designed to transmit a signal without noise or interference capture.

    Generally shielded ca

    les with metal mesh and are internally compensated witha low capacity, and otherwise distort the measures of high frequency signals. There attenuator pro

    es that reduce the input voltage

    y a factor of 10, 100 or1000 times, so that the oscilloscope can record much higher voltages which can

    e measured directly.

    101

    INPUT CONNECTIONS oscilloscopes typically provide two inputs (channels) safety pin 4 mm shielded(input B input A red and gray) and a security entrance for 4 mm

    anana plug common (COM). Input A: You can always use the entry to red for all unique entries measurements are possi

    le with the measuring instrument.Wiring Panel pro

    esOoh! Admittedly, I have again forgotten

    I've said time and again that

    Input B: To take measurements at two different signals can

    e used with gray inp

    ut B input A red.

    treat me with care!

  • 8/8/2019 34080945 Automotive Electronics

    25/29

    COM: You can use the

    lack terminal to COM as a single mass measurements of lowfrequency and continuity measurements, capacity and diodes.

    102

    THE PROBES

    To avoid electric shock or fire, use only one connection COM (common), or ensurethat all connections to COM are the same potential (refer to the same mass)

    103

    CONCEPTS OF SIGNALWAVE TensionSignal that is repeated over time

    WAVE CYCLEPortion of wave that repeats

    WAVEFORMGraphical representation of a signal that shows the time on the horizontal axisand voltage on the vertical axis104

    Time

    MOST COMMON FORMS OF WAVESSINE WAVE: The voltage from the mains for domestic use, the one created

    y an alternator

    efore

    eing corrected or a Lam

    da pro

    e.

    Sine Wave

    Damped sine wave105

    MOST COMMON FORMS OF WAVESSQUARE WAVE: It is the signal that can generate a Hall sensor, phase sensor, speedometer, etc. V wave generated

    y a Hall sensor power

    t106

    MOST COMMON FORMS OF WAVESCOMPLEX WAVE: Those that can

    e a com

    ination of several, like those given in the primary and secondary ignition. V wave generated

    y the secondary ignition

    t107

    Concepts: PERIOD The signal period is the time it takes for a wave to make a complete cycle.

    PERIOD10 ms x 4 divisions = 40 msec

    108

    EXERCISE 1 Indicate the period of the following waveforms3 divisions

  • 8/8/2019 34080945 Automotive Electronics

    26/29

    5 divisions

    2 ms x 3 divisions = 6 ms

    5 ms x 5 divisions = 25 ms109

    Concepts: FREQUENCY Frequency is the num

    er of wave cycles that occur in a given time, usually in1 second. ie: Frequency = 1/Periodo First calculate the "Period"PERIOD 10 msec x 4 divisions = 40 msec

    Su

    stituting in the formula Period Frequency:

    f = 1 / p

    f = 1/0.040 sec

    110

    Frequency = 50 Hz

    FREQUENCY UNITS The unit of frequency is Hertz (Hz). One Hertz equals one cycle per second (1ciclo/seg). The Hertz has in turn decimal multiples,

    eing the most widely used multiples the kilohertz (kHz) and Megahertz (MHz). 1 KHz = 1000 Hz 1 MHz = 1,000,000 Hz 1 kHz 1 Hz = 0.001 Hz = 0.000001 MHz111

    Exercise 2 Calculate the frequency of the following waveforms

    3 divisions

    5 divisions

    Period = 2 ms x 3 = 6 ms div 1/0.006seg = Frequency = 166.6 Hz

    Period = 5 ms x 5 div = 25 ms = 1/0.025seg Frequency = 40 Hz112

    FREQUENCY UNITSHave you noticed how ......? The period in seconds, is the frequency in Hertz From Period in milliseconds, is the frequency in kilohertz From Period in microseconds, is the frequencyin megahertz

    113

    Exercise 3 Draw the waveform of the screen on the left, on the right, taking into accountthe time

    ase

    114

    Concepts: RANGE (I) The signal amplitude is the height or distance that has the waveform with resp

    ect to the zero reference line. Width:2 volts x 6 divisions = 12 Volts

  • 8/8/2019 34080945 Automotive Electronics

    27/29

    115

    Concepts: RANGE (II) The amplitude of a sine wave is usually given as the rms value, which equals approximately 70.7% of the maximum peak value.

    1. Peak to Peak Voltage 10 volts x 6 = 60 V div

    Fe

    ruary 1 March 4

    2. Maximum Peak Voltage 10 volts x 3 div = 30 V 3. Minimum Peak Voltage 10 voltsx 3 div = 30 V 4. Effective Voltage 30 volts x 0.707 = 21.2 V116

    EXERCISE 4 Indicate in the waveform following its various parameters.

    RANGE2 x 6 volt div. = 12 volts

    FREQUENCYPeriod = 10 ms f = 1 / p, f = 1 / 0, 010 sec

    f = 100 Hz117

    EXERCISE 5 Indicate in the waveform following its various parameters.

    Peak to Peak Voltage 2 volts x 6 div. = 12 volts peak voltage 2 volts x 3 div. Peak Voltage = 6 volts at least 2 volts x 3 div. Effective Voltage = 6 volts 6 volts x 0707 = 4.2 volts Frequencyf = 1 / p = 1 / 0, 004seg = 250 Hz

    118

    OSCILLOSCOPE CONNECTIONS OF EXERCISE 6The circuit shown in the figure, has a rate of 1mseg operation, ie, the switch changes its position in that interval. Draw the signal to detect the oscilloscope, indicating the connection drawing. Determines the scale of tension and time too

    serve the signal accurately.

    119

    OSCILLOSCOPE CONNECTIONS OF EXERCISE 7The circuit shown in the figure, has a rate of 1mseg operation, ie, the switch changes its position in that interval. Draw the signal to detect the oscilloscope, indicating the connection drawing. Determines the scale of tension and time toaccurately o

    serve the signal

    120

    OSCILLOSCOPE CONNECTIONS OF EXERCISE 8The circuit shown in the figure, has a rate of 1mseg operation, ie, the switch changes its position in that interval. Draw the signal to detect the oscilloscope, indicating the connection drawing. Determines the scale of tension and time toaccurately o

    serve the signal

    121

    OSCILLOSCOPE CONNECTIONS OF EXERCISE 9Draw the signal to detect the oscilloscope, indicating the connection drawing. D

  • 8/8/2019 34080945 Automotive Electronics

    28/29

    etermines the scale of tension and time to accurately o

    serve the signal circuitshown in Figure, has a rate of operation of 1mseg, ie, the switch changes its position in that interval.

    122

    Concepts: PULSE

    Occurs when detects the momentary activation of an item, for example, the flash of a lamp Many actuators in the vehicle receives a pulse train at a fixed frequency, to modulate their functioning.V12V

    f = 1 / p60% 40%10 ms 20 ms

    f = 1 / 0, 01 sect / ms

    0V

    Period = 100%

    f = 100 Hz

    Modulation is o

    tained

    y varying the duty cycle (DWELL) of a fixed frequencysignal, ie modifying the activation and deactivation time within the period.123

    Automotive OscilloscopeIn the oscilloscopes used in automotive, usually appear on the screen numericall

    y different magnitudes selected through a menu.

    124

    EXERCISE 10 The next waveform shows that Duty Cycle, Dwell, and RCA have.

    25% D 75% D

    40% D 60% D

    125

    SIGNAL INJECTIONInjection relay

    ECU

    Amplifier

    30 Battery

    Ignition key

    The electrical injectors are controlled

    y the ECU

    y negative excitement, there

    fore,

    e in the terminal where you connect the oscilloscope126

  • 8/8/2019 34080945 Automotive Electronics

    29/29

    SIGNAL LAMBDA ()To ana

    yze this signa

    we se

    ected a sma

    base vo

    tage and a

    arge time base. L

    ambda probe generates a votage of 100-900 mV, and its period is approximate

    y 1

    sec at an engine speed of about 2000 rpm

    127

    SIGNAL CONTROL OPERATOR OF TWO COILS IDLETo ana

    yze this signa

    , use a two-channe

    osci

    oscope. Observe the onset times

    (Dwe

    ) from each of the coi

    s, they must be opposed.

    128