1. Automotive Service Modern Auto Tech Study Guide Chapter 8
Pages
Electricity & Electronics
37 Points

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1. ___________________ is the movement of electrons (-) from atom to atom.
Every vehicle system uses some type of electrical or electronic part, so its
important to know as much as possible about electricity
Electricity
Pneumatics
Hydraulics

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2. __________________ are materials that allow electron flow.
They have less than 4 electrons in their outer orbits.
__________________ are materials that do not allow flow.
They have more than 4 electrons in their outer orbits.

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3. The 3 basic elements of electricity & units of electrical measurement are:
________________ (V or E) which is electromotive force, pressure or the
push that causes flow (emf)
________________ (A or I) which is the intensity or rate of electron flow in
a conductive path (amps)
______________ (O or R) which is the opposition to electron flow (ohms)
Voltage
Amperage
Resistance

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4. Two theories have been used to explain how current flows through a circuit.
______ theory states that current flows from positive to negative (+ to -)
______ theory states that current flows from negative to positive (- to +)

6. Automotive Service 5. A circuit is a path for electrical flow.
A circuit must have three things to be complete:
a power _____________: chemical such as a battery or mechanical
such as a generator or alternator
a ________, often called a consumer, which uses the electricity and
often “names the circuit”.
a set of ____________________, such as wiring, metal parts, fuses &
switches as a conductive path
Source
Load
Conductors

7. Automotive Service Consumer – Has Resistance & Names the Circuit
BEST PRACTICE: A circuit must have three things to be complete:
Consumer – Has Resistance & Names the Circuit
Source – Has the Voltage
Conductive Path – Carries the Amperage

8. Automotive Service 6. Circuits can be one of three types:
____________, where all of the consumers are in-line
like links of a chain
___________________, where each consumer has its own leg
arranged like rungs of a ladder
____________ - ________________, which is a
combination of the previous two
parallel
series
series-
parallel

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series
parallel

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In a ______-________ or frame-ground type of circuit, the vehicle’s
____________, ________, and the ____________ block serve as a ground or return path to complete the circuit back to the source (battery).
one - wire
Body
Frame
Engine

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8. __________ ______ is the mathematical relationship between
volts, ohms, and amps in every circuit.
Using V, A, & O, write the 3 basic ohms law equations:
Georg Simon Ohm was born on March 16, 1789 in the city of Erlangen in Bavaria, which is now Germany. He died on July 6, 1854 in Munich, Bavaria, Germany.

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14. Automotive Service 12 Volt Source 12 Volts 6 Volts 0 Volts
If the #921 Bulb has 3 Ohms, the Total Resistance is 6Ω.
If the Total Resistance is 6 Ω, then the Current Flow is 2 Amps.

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V = A x O
A = V ÷ O
O = V ÷ A

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9. A _________ allows a circuit to be turned on or off.
A _______ protects components against amperage overloads due to
short circuits which are accidental low resistance connections that can melt
components.
Fuse, Switch
Breaker, Switch
Switch, Fuse

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10. ______________ links & circuit _____________ protect components against
large amperage overloads.
Fusible Links
Circuit Breakers

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__________ are electro-magnetically operated devices that allow a small
switch to control large current.
Diodes
Relays
Transistors

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12. The term __________ _________ is used to describe electrical components
and circuits that use parts made of semiconductor materials.
**They can control current flow in circuits without moving parts.
Solid State
Base Line
Outta Sight

20. Automotive Service A ______ is a semiconductor device that Diode
allows current flow in one direction only.
Diode
Relay
Transistor
Used to change AC to DC

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______________________ are semiconductor devices that work like a solid
state relays, they will switch electrical flow without the use of moving parts.
Diodes
Relays
Transistors

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A _____________________ absorbs unwanted electrical pulses that
would otherwise cause radio static.
Diode
Relay
Capacitor

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16. Wire size in circuits is determined by the __________ of its metal conductor.
Circumference
Diameter
Length

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__________ wires and test lights are quick test tools used to
diagnose circuit problems
Bumper
Plumper
Jumper

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_______________________, also called DVOM’s, DMM’s, or just VOM’s
are used to measure circuits.
Multi-meters
Tachometers
Scan Tools

26. Automotive Service A _______________ gets connected to a circuit in
parallel to measure EMF or Electro Motive Force
Ohmmeter
Voltmeter
Ammeter

27. Automotive Service An ________________ connects to a circuit in
series or with an inductive pickup to measure current.
Ohmmeter
Voltmeter
Ammeter
Amps

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21. When using the _____________ function of a DMM to measure resistance,
always disconnect the power source from the components being tested.
NOTE: OL or ∞ on an ohmmeter indicates an open circuit.
Ohmmeter
Voltmeter
Ammeter
2kΩ to 12kΩ per foot
on TRVS Plug Wires

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22. A _______ _______ is a diagnostic tool that helps pinpoint problems with
onboard computer systems.
It plugs into a vehicle’s data link connector (DLC) & provides a data stream
of information from the PCM.
Scan Tool
Oscilloscope
Digital Multi-Meter

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