basic electrical systems theory and repair
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Basic Electrical Systems Theory and Repair. Chapter 29 Page 387. So, Where is Electronics in a Car. Everywhere Antilock brakes, engines, emissions, dash, fuels system, transmissions, tires, suspension, windows, safety systems, lighting. ----Well, I could go on and on and on. The Basics. - PowerPoint PPT PresentationTRANSCRIPT
Basic Electrical Basic Electrical Systems Theory Systems Theory
and Repairand RepairChapter 29Chapter 29
Page 387Page 387
So, Where is Electronics So, Where is Electronics in a Carin a Car
EverywhereEverywhere Antilock brakes, engines, Antilock brakes, engines,
emissions, dash, fuels system, emissions, dash, fuels system, transmissions, tires, suspension, transmissions, tires, suspension, windows, safety systems, lighting.windows, safety systems, lighting.
----Well, I could go on and on and ----Well, I could go on and on and on. on.
The BasicsThe Basics
AtomsAtoms
Negative
Positive
Conductors and Conductors and InsulatorsInsulators
ConductorsConductors
Conductors
A good conductor must not have more than four electrons in the outer valence ring of an atom. Copper is one of the best conductors; along with aluminum and gold, conductors have one electron in the outer valence ring.
InsulatorsInsulators
Insulators
A good insulator must have more than four electrons in the outer valence ring of an atom. Rubber, glass, and porcelain are the best insulators with many electrons in the outer valence ring.
Electrical FlowElectrical Flow
Electron MovementElectron Movement
This is what we are taught!Positive to Negative
This is the way it really is!Negative to Positive
Wiring is coated with PVC, a flexible Wiring is coated with PVC, a flexible plastic to insulate the copper wiring. plastic to insulate the copper wiring.
Color ChartColor Chart
Circuit RequirementsCircuit Requirements== A full circle is providedA full circle is provided
Source
(Battery)
12 v
Complete path
Load
(light)
+
_
Switch
Source – Battery or voltage supplyLoad – Electrical components, lights, radio, etc.Complete path for electron flow – Wires and connections
Circuit DevicesCircuit Devices Controls DevicesControls Devices
Protection DevicesProtection Devices
Fuses and Circuit Breakers Protect form Overloads
Switches for on and off
Fuses and Circuit Fuses and Circuit BreakersBreakers
Other Symbols
Electrical TermsElectrical Terms
VoltageVoltage- Also called Electromotive - Also called Electromotive Force, Pressure of electricity or the Force, Pressure of electricity or the amount of force it takes to move amount of force it takes to move electrons. Measured in electrons. Measured in voltsvolts..
Current-Current- The movement or flow of The movement or flow of electrons, measured in amperes or electrons, measured in amperes or ampsamps for short.for short.
ResistanceResistance--Anything that impedes or slows the flow of electrons. Measured in ohms.
More Electrical TermsMore Electrical Terms
AC – Alternating Current (shop AC – Alternating Current (shop lights and equipment)lights and equipment)
DC – Direct Current (Auto battery DC – Direct Current (Auto battery and most systems)and most systems)
Auto voltage used is normally Auto voltage used is normally between 12 and 15 voltsbetween 12 and 15 volts
Circuit TypesCircuit Types
Series
Parallel
Combination
Series CircuitSeries Circuit
Series CircuitsSeries Circuits
• Series circuits provide only one path for electron flow through a circuit.
• When one component fails, the remaining components quit working.
Light
12 v
Light
Light
Parallel CircuitParallel Circuit
Parallel CircuitsParallel Circuits
• Parallel circuits provide two or more paths for electron flow through a circuit.
• When one component fails, the remaining components are not affected.
12 v Lights
Combination
The simplest type is to use a switch The simplest type is to use a switch in the first part of the circuit (series) in the first part of the circuit (series) and the rest of the circuit is wired in and the rest of the circuit is wired in parallel.parallel.
12 v Lights
Ohm’s LawOhm’s Law
Greg Simon Ohm (1787 – 1854)
Ohm’s Law: It takes one volt to push one ampere of current through one ohm of resistance.
*Look at page 394 for more.
Ohm’s LawOhm’s Law
E
I R
E = Voltage (Electromotive Force)
I = Current (Intensity)
R = Resistance (Ohms)
E = IR
I = E/R
R = E\I
Ohm’s LawOhm’s LawE
I R
E = IR
I = E / R
R = E \ I
4 ohms
3 amps
12 volts
E = IR
12 = 3 X 4
I = E / R
3 = 12 / 4
R = E / I
4 = 12 / 3
MagnetismMagnetism
Laws of magnetism:
1. Like poles repel each other.
2. Unlike poles attract each other.
3. The attractive force increases as the distance between the magnets decreases.
N SN S
N S S N
Magnetic FieldsMagnetic Fields
MagnetismMagnetism
Magnetic Field-
Occurs when a current is flowing through a conductor.
Electromagnets-
Artificially creating a magnetic field. A coil of wire with a voltage applied.
ElectromagnetsElectromagnets
M
Solenoid or Relay
Starter
Switch
Battery
ElectromagnetsElectromagnets
ResistorsResistors
A Few More TermsA Few More Terms
SemiconductorsSemiconductors- Can act as both - Can act as both insulator and conductor.insulator and conductor.
DiodeDiode- an electronic one way check - an electronic one way check valve, it allows flow one way but valve, it allows flow one way but doesn’t allow it to reverse the other doesn’t allow it to reverse the other way.way.
TransistorTransistor- electronic relay. Its very - electronic relay. Its very fast, and no moving parts.fast, and no moving parts.
Basic TestsBasic Tests
MetersMeters Analog and DigitalAnalog and Digital
Digital Volt-ohm Meter (DVOM) or Digital Multimeter (DMM)
MeasurementsMeasurements
Voltage TestingVoltage Testing
Voltage CheckVoltage Check
Testing Voltage After Testing Voltage After SwitchSwitch
Open = wire broke or fried wire
Circuit TestCircuit Test
1
2
2
1 = 12 v
2 = 12v
3 = 12v
3
Continuity TestingContinuity Testing
Ohmmeter TestOhmmeter Test
Diode CheckDiode CheckDiode is a one way street only. Reversing the multimeter leads will tell us if the voltage is allows one way and is stopped the opposite way. If it doesn’t do this toss the diode.
.000 one way and 1. the other.
Testing Device with Testing Device with Ohmmeter Ohmmeter
with Power Removedwith Power Removed
Continuity Should be .000 if Good
Infinity Should be 1. if Bad
Testing AmpsTesting AmpsNeed to change red probe lead to Amp on meter
Test Light Test Light
Test LightTest Light
Using a Jumper WireUsing a Jumper Wire
Bypassing Ground
Bypass a Switch with Bypass a Switch with Jumper WiresJumper Wires
Circuit DefectsCircuit Defects
Open
Incomplete or broken circuit. The circuits quits working.
Short
Two wires unintentionally connecting with each other. Could cause more than one component to operate.
Circuit DefectsCircuit Defects
Ground
When a positive and negative wire contact each other. Could cause sparking and extreme heat due to high current flow. Very low resistance blows fuses, circuit breakers, or fusible links.
Circuit DefectsCircuit Defects
Open Circuits
Circuit DefectsCircuit Defects
Short Circuits
Circuit DefectsCircuit Defects
Ground Circuits
Your Job.Your Job. Complete chapter Questions 1-15 Complete chapter Questions 1-15
(review) and 1-10 (ASE-style). Page (review) and 1-10 (ASE-style). Page 401-402401-402
Write on a separate paper and write out Write on a separate paper and write out the complete question and your answer. the complete question and your answer. ( do not write the other answer options). ( do not write the other answer options).
Complete the chapter worksheet (I will Complete the chapter worksheet (I will give it out). You may write on it. give it out). You may write on it.
File all items in your note book.File all items in your note book. Notebooks will be graded in the future.Notebooks will be graded in the future.