Automotive Service Modern Auto Tech Study Guide Chapter 8 Pages 97 ­ 110 Electricity & Electronics 37 Points

Automotive Service 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

Automotive Service 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.

Automotive Service 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

Automotive Service 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 +)

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

Automotive Service 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

Automotive Service 6. Circuits can be one of three types:

____________, where all of the consumers are in­line 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

series

parallel

series­ parallel

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series

parallel

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Automotive Service 7. In a ______­________ or frame­ground 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

Automotive Service 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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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.

12 Volt Source

12 Volts

6 Volts

0 Volts

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V = A x O

A = V ÷ O

O = V ÷ A

Automotive Service 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

Automotive Service 10. ______________ links & circuit _____________ protect components against

large amperage overloads.

Fusible Links

Circuit Breakers

Automotive Service 11. __________ are electro­magnetically operated devices that allow a small

switch to control large current.

Diodes Relays

Transistors

Automotive Service 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

Automotive Service 13. A ______ is a semiconductor device that

allows current flow in one direction only. Diode Relay

Transistor

Used to change AC to DC

Automotive Service 14. ______________________ are semiconductor devices that work like a solid

state relays, they will switch electrical flow without the use of moving parts.

Diodes Relays

Transistors

Automotive Service 15. A _____________________ absorbs unwanted electrical pulses that

would otherwise cause radio static.

Diode Relay

Capacitor

Automotive Service 16. Wire size in circuits is determined by the __________ of its metal conductor.

Circumference Diameter Length

Automotive Service 17. __________ wires and test lights are quick test tools used to

diagnose circuit problems

Bumper Plumper Jumper

Automotive Service 18. _______________________, also called DVOM’s, DMM’s, or just VOM’s

are used to measure circuits.

Multi­meters Tachometers Scan Tools

Automotive Service 19. A _______________ gets connected to a circuit in

parallel to measure EMF or Electro Motive Force

Ohmmeter Voltmeter Ammeter

Automotive Service 20. An ________________ connects to a circuit in

series or with an inductive pickup to measure current. Ohmmeter Voltmeter Ammeter

Amps

Automotive Service 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.

2kΩ to 12kΩ per foot on TRVS Plug Wires

Ohmmeter Voltmeter Ammeter

Automotive Service 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 Multi­Meter

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