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
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.
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
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 +)
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
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
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 seriesparallel
series parallel
7. 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
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.
12 Volts 6 Volts 0 Volts 12 Volt Source 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.
V = A x O A = V O O = V A
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
10. links & circuit protect components against large amperage overloads. Fusible Links Circuit Breakers
11. are electro magnetically operated devices that allow a small switch to control large current. Diodes Relays Transistors
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
13. A is a semiconductor device that allows current flow in one direction only. Diode Relay Transistor Used to change AC to DC
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
15. A absorbs unwanted electrical pulses that would otherwise cause radio static. Diode Relay Capacitor
16. Wire size in circuits is determined by the of its metal conductor. Circumference Diameter Length
17. wires and test lights are quick test tools used to diagnose circuit problems Bumper Plumper Jumper
18., also called DVOM s, DMM s, or just VOM s are used to measure circuits. Multi meters Tachometers Scan Tools
19. A gets connected to a circuit in parallel to measure EMF or Electro Motive Force Ohmmeter Voltmeter Ammeter
20. An connects to a circuit in series or with an inductive pickup to measure current. Ohmmeter Voltmeter Ammeter Amps
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
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