-
Means atom has an imbalance of electrical charges due to the gain or loss of electrons.
Ion
-
an atom with more electrons than protons has an overall negative chargerepelling forece Wants to push one of the electrons away from this atom
negative ion
-
Deficiency of electronsIt is exerting and attracting force on the electrons to try to pull one into its atom from another atom
positive ion
-
The flow of electrons from Atom to atom; the basic concept of electricity
current flow
-
materials that can give up or accept electrons easily.
conductors
-
materials that cannot give up or accept electrons easily.
insulators
-
located on the outer/valance ring, loosely held by the nucleus and are free to move form one atom to another when an electrical potential (pressure) is applied.
free electrons
-
atoms with fewer electrons in the valance ring are the best _____, one electron being the best ________ material.
conductors
-
plastic, ceramic,does Not allow current flow because it has no review or very few free electrons, and the electrons it does have, cannot move freely; therefore, prevents the movement of Electrons when an electrical potential is appliedmade up of atoms that have five to eight valance ring electrons.
insulators
-
materials that conduct Electricity more easily than insulators, but not as well as conductors.Silicone
Semi Conductor
-
What kind of material is this based on the electrons in the valance ring.
conductor
-
what kind of material is this based on the electrons in the valance ring.
Insulator
-
What kind of material is this based on the Number of electrons in the valence ring
Semi Conductor
-
Electrons being pushed away from the negative side and pulled to the positive side. this movement is current flow
-
what kind of ion is this?
negative ion
-
what kind of ion is this?
Positive ion
-
Atoms that have four valance ring electrons are considered ______.One electron away from being an insulator or a conductor.if an Electron is added, it becomes an insulator; if an electron is removed, it becomes a conductor.used as a switch to control whether electrons flow throught the material or are stopped by it.
Semiconductors
-
Three Things necessary for the flow of elctrons
- Free Electrons
- A complete pathway, called a circuit.
- A force that makes them move.
-
- In excess of electrons on the negative side of the battery pushes electrons toward the positive side of the battery which is pulling on the electrons as well. The forces called voltage. The current flow is called Amperage.
-
The force that motivates electrons to move through a circuit.
electromotive Force/ Voltage
-
Electrical current is the flow of Electrons, it is natural to say that the direction of current is the direction in which the free electrons move - from negative to positive
Electron theory
-
Before the discovery that electrons are negatively charged, it was thought that the natural way for them to flow was from positive to negative.
Conventional theory
-
What are the four factors that determine the level of electrical resistance
- Type of material
- Length of conductor
- Diameter of the conductor
- Temperature of the conductor
-
measured in Ohms
Electrical resistance
-
Component designed to extract energy from the current flow
Resistor
-
Roads are like wires
Stop lights are like switches
Businesses are like electrical devices where work happens
Cars are like Electrons that deliver the workers to the workplace
Electrical circuit
-
Basic electical circuits
- Power supply
- Fuse
- Switch
- component That performs work
- wires connecting them all together
-
Measured in amps
Flow of Electrons
-
Complex electrical circuit
- Power source
- Circuit protection device
- Control mechanism
- Load
- Connecting wires
-
-
Three basic units of electrical measurement
Volts, amps, ohms
-
Potential or electrical pressure difference between two points in an electrical circuit
Voltage
-
Measures the difference in voltage between two meter leads
Volt meter
-
Unit used to describe how much current flow or how many electrons are flowing at a given point in one second when work is being performed
ampere, amp
-
Unit used to describe the amount of electrical resistance in a circuit or component
Ohm
-
How is resistance measured?
The component or wire must be disconnected from the rest of the circuit. The ohmmeter pushes a small amount of current through the part being tested. The amount of resistance in the component changes the amount of current that the ohmmeter can push through the component. The more current the ohmmeter can push through the component the lower the resistance will read on the Ohmmeter.
-
Pressure (volts) in electrical systems is similar to pressure in water system. The pressure wants to even out.
-
1 amp equals 6.28 billion piles of Electrons, each pile containing a billion electrons.
-
Current flow (amps) in an electrical circuit is like water flowing through a pipe.
-
Resistance (ohms) in an electrical circuit is like a restriction in a water hose.
-
-
The supply side is the positive side of The circuit, and the return site is the negative side of the circuit
What theory is this?
Conventional theory
-
Refers to the wires and components that originate at the positive post of the battery and then at either a switch or a load whichever occurs first
The power or feed side of a circuit
-
Term used by technicians to indicate the portion of the circuit that returns current flow to the negative side of the battery
Starts at the negative post of the battery and ends at either a load or a switch
Ground
-
Loose or dirty ground connections create a point of high _____ in the circuit. Resulting in Lower current flow and excessive voltage drop.
Resistance
-
Vehicles with brick lights flashing along with or opposite to turn signal lights.
Issue encountered where electricity finds alternative paths to ground
-
Two fundamental types of current flow
- Direct Current (DC)
- Alternating Current (AC)
-
Produced by a battery,
maintains the same positive and negative polarity
current flows in one direction only
Direct Current
-
What are the characteristics of DC
- Fixed polarity of the applied voltage
- The flow of charges in only one direction
-
The type of current in your home electricity supply
AC
-
AC is produced in what is called a
Sine wave
-
Measurement of frequency and indicates the number of cycles per second
Hertz
-
AC is used in vehicles to
Alternators use it to create current flow to charge the battery and run the electrical accessories
-
How can AC be effectively put to use in the DC electrical system
AC is first transformed to DC before it leaves the alternator.
-
- Wave forms
- direct Current
- Alternating current
-
why is AC used in the electric motors on most hybrid vehicles
Those motors generally require high amounts of electrical power and because AC is more efficient than DC AC is more advantageous for that application
-
In general, electrical components are designed to work on?
Either AC or DC, but not both.
Dc motor will not work on AC, and vice versa.
-
The technician can explain the difference between direct and alternating current.
- DC and AC are Two forms of electricity that are produced differently and have different uses DC electricity is the simpler form it starts in one place and then flows in the same direction to its destination. Ac electricity flows in One Direction for a period of time then changes direction over and over again continuously.
- In Modem Automotive applications, ac electricity is generated by the alternator using electromagnets. Ac electricity is converted to DC or rectified, by diodes in the alternator before being supplied to the vehicle's electrical systems or being stored in the battery.
-
Continuity, Open, short, and High Resistance (Voltage Drop)
Often used to describe a circuits or components condition.
-
Achieved one in electrical circuit has a continuous and uninterrupted electrical connection and is thereby capable of conducting current and working as designed
Continuity
-
Means there is a break in the circuit and current cannot flow past the break
No continuity
-
how can circuit continuity be measured with a digital voltt ohmeter
Using the ohms setting between two points in the circuit
-
Even though a circuit has continuity what might still be wrong with it?
Although the circuit has continuity, it may have only one small strand of wire instead of the original 6 to 50 strands it had
-
Describes a low voltage circuit that does not have a complete circuit and therefore cannot conduct current
Open
-
Can be used to describe a fault in a circuit
open
-
How is a multimeter or a test lamp used to test for an open circuit?
By placing one end on the positive and testing for continuity
-
An open circuit has infinite _____.
Resistance
-
Describes a circuit fault in which current takes a shorter path in terms of resistance through an accidental or unintended route
short
-
Causes abnormally high current flow in the circuit and May cause the circuit protection devices such as fuses or circuit breakers to open the circuit
Short
-
how would you describe the condition of this component?
short circuit
-
describe a short to ground
Circuit has an unintended path directly from a powered wire to ground
bypasses the load
-
Describe short to power
The circuit has an unintended path directly to a power source
bypasses a switch
-
What is the third type of short?
From a switch ground wire directly to ground
-
What are some types of electrical faults?
Unintended high resistance in a circuit
-
Causes a reduction in current flow in the circuit as well as a dropping voltage at the resistance
Unintended high resistance
-
Causes in overheating condition at the area of resistance, Which can melt wire insulation or plastic connectors
Unintended high resistance
-
Condition caused by a number of faults including corroded or lose harness connectors, wire that is too thin for the circuit current flow, incorrectly connected terminals, and poorly soldiered joints
Unintended high resistance
-
how is this a short to ground?
- Ask a teacher because I'm not sure
- Maybe something to do with the PCM slash TCM
In this case the circuit has an unintended path directly from a powered wire to ground. Example, if the wire from the brake switch to the brake light rubs through the wire insulation on a sharp edge of a body panel the bare wire may make contact with the metal panel and cause a short to ground when the brake pedal is pressed. A short ground causes increased current flow and will typically blow the circuit fuse
-
Explain a shorts of power
- The circuit has an unintended path directly to a power source
- An example is two wires in a harness that have melted together one that applies power to the blower motor and one that feeds power from the brake light switch to the brake lights in this example turning on the ignition switch would cause the brake lights to come on because power would be sent to the blower fuse and then, due to the short in wiring, to the brake lights.
-
Explain a short from a Switz ground wire directly to ground
This can happen on circuits like fuel injectors, where the switch provides a ground for the injector. If the wire between the injector and the switch shorts out to ground, the injector will continuously spray fuel, even if the switch is open.
-
What are some of the characteristics of an unintended high resistance in a circuit?
- Causes a reduction in current flow in the circuit as well as a drop in voltage at the resistance
- These result in the in the intended circuit device not operating effectively or at all.
- Can also also cause an overheating condition at the area of resistance, which can melt wire insulation or plastic connectors.
- This condition is caused by a number of faults, including corroded or loose harness connectors, wire that is too thin for the circuit current flow, incorrectly connected terminals, and poorly soldered joints.
-
AS-62: Short Circuit: The technician can demonstrate an understanding of the processes used to locate a short circuit in an electrical electronic system.
Two types of short circuit can occur in electrical systems. Short to ground electrical current finds its way to the ground before it was intended, usually due to compromised wiring insulation that allows wiring to touch the metal vehicle body. In a short to power, a circuit is exposed to voltage flowing in another circuit, generally also due to broken wiring insulation. The effect of either type of short will depend on the layout of the circuit and where the short occurs in relation to the load.
The most common indicator of a short circuit is a fuse blowing due to excessive current flow. Traditionally diagnosing the location of the short has required being able to segment the circuit by by disconnecting fuses, component switches, or harness plugs and checking individual sections of the circuit for integrity. Electronic short circuit finders are now available that send an electrical signal along the circuit. A receiver is run along the circuit until it stops receiving a signal at which point the location of the short has been found
-
Technician tip: Resistance and Heat
Because current flowing through a resistance causes heat, you can sometimes locate the high resistance in the circuit just by feeling the wires and connections. For example, if one of the battery posts is corroded between the post and the battery cable, a voltage drop will be present when the starter is engaged. If you operate the starter for several seconds and then feel each battery terminal, the 1 with excessive resistance will be warmer than the other terminal.
-
To locate Unintended voltage drop, what conditions must be present?
There must be excessive resistance, and the circuit must be activated.
-
A voltage drop in a circuit indicates that?
There is resistance present and current is flowing or trying to flow through the resistance.
-
A high resistance in the main battery cable to the starter motor causes . . .
The starter to crank the engine over slowly or not at all.
-
An unintended voltage drop in the headlight circuit reduces the available voltage for the light causing the lights to . . .
be dim
-
A voltage drop can be measured in a circuit by placing a voltmeter
Across two different points in a circuit while the circuit is being operated
-
Explain what is going on here
To measure the voltage drop in the main positive battery cable to the starter motor, the volt meters black lead is placed on the positive battery lead, and the red lead is placed on the main battery lead of the starter motor; the voltage drop is then read on the meter while the engine is cranked. If excessive, the table or connections would have to be replaced or repaired.
|
|