CCNA 1. Networking Basics v3.1.1 Student Lab Manual (796248), страница 6
Текст из файла (страница 6)
The transformer converts theAC voltage to DC voltage for use by the device. Some AC outlets can provide a higher voltage of220V for use by devices and equipment with heavier requirements, such as clothes dryers and arcwelders.Prior to starting the lab, the teacher or lab assistant should have one multimeter available for eachteam of students, and various items for testing voltage.
Work in teams of two. The followingresources will be required:•Fluke 110, 12B, or equivalent multimeter•An assortment of batteries: A cell, C cell, D cell, 9 Volts, 6 V lantern•Duplex wall outlet, typically 120v•Power supply for laptop or other networking electrical deviceThe following resources are optional:•A lemon with a galvanized nail stuck in one side and a piece of uninsulated copper wire stuck inthe opposite side•Solar cell with leads attached•Homemade generator, wire wound around a pencil 50 times and a magnetStep 1 Select the Proper Voltage ScaleThe method of selecting the voltage scale will vary depending on the type of meter. The Fluke 110has two separate positions for voltage, one position with a wave over it for AC and one position witha solid and dashed line above it for DC.
With the Fluke 12B, move the rotary selector to the V symbolfor voltage, black V, in order to be able to measure voltage. Press the button that has the VDC andVAC symbol to select between direct current (DC) and alternating current (AC) measurements.direct current measurements: The screen will show a V, for voltage, with a series of dots and aline over the top.
There are several scales available depending on the voltage to be measured. Theystart from millivolts to voltages up to hundreds of volts. Millivolts is abbreviated mV = 1000th of avolt. Use the Range button to change the range of DC voltage to be measured based on whatvoltage is expected to be measured. Batteries less than 15 volts can typically be measuredaccurately with the VDC scale and 0.0 range. DC voltage measurements can be used to determine ifbatteries are good or if there is voltage coming out of an AC adapter. These are common and areused with hubs, modems, laptops, printers, and other peripherals.
These adapters can take walloutlet AC voltage and step it down to lower AC voltages for the device attached or can convert theAC voltage to DC and step it down. Check the back of the adapter to see what the input, AC, andoutput voltages, AC or DC, should be.alternating current measurements: The screen will show a V, for voltage, with a tilde (~) after it.This represents alternating current. There are several scales available depending on the voltage tobe measured.
They start from millivolts to voltages up to hundreds of volts. Millivolts is abbreviatedmV = 1000th of a volt. Use the Range button to change the range of AC voltage to be measuredbased on what voltage is expected to be measured. Voltage from power outlets 120v or greater cantypically be measured accurately with the VAC scale and 0.0 range. AC voltage measurements areuseful in determining if there is adequate voltage coming from an AC outlet to power the equipmentplugged in.2-3CCNA 1: Networking Basics v 3.1 - Lab 3.1.2Copyright 2003, Cisco Systems, Inc.Step 2Use a Fluke 110, 12B or equivalent multimeter to measure the voltage of each of the following. Besure to turn the meter off when finished.Item to Measure the Voltage OfSet Selector andRange Scale toVoltage ReadingBatteries: A cell (AA, AAA), C cell, D cell,9 Volts, 6 V lanternDuplex wall outlet (typically 120v)Power supply (converts AC to lower AC or DC) forlaptop, mobile phone, or other networking electricaldevice(Optional) A lemon with a galvanized nail stuck inone side and a piece of uninsulated copper wirestuck in the opposite sideReflectionWhy might it be important to measure voltage when troubleshooting a network?___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________3-3CCNA 1: Networking Basics v 3.1 - Lab 3.1.2Copyright 2003, Cisco Systems, Inc.Lab 3.1.3 Resistance MeasurementObjective•Demonstrate the ability to measure resistance and continuity with the multimeter.BackgroundThe digital multimeter is a versatile testing and troubleshooting device.
This lab covers resistancemeasurements and related measurements called, continuity. Resistance is measured in Ohms,indicated by the Greek letter Omega or Ω. Copper wire conductors such as those commonly used innetwork cabling, normally have very low resistance or good continuity when checked from end toend. If there is a break in the wire, it is called “open,” which creates very high resistance. Air hasnearly infinite resistance, indicated by the infinity symbol or ∞.The multimeter has a battery inside. The battery is used to test the resistance of a wire conductor orwire sheathing insulator. When the probes are applied to the ends of a conductor, the battery currentflows and the meter measures the resistance encountered. If the battery in the multimeter is low ordead, it must be replaced or the multimeter will not be able to take resistance measurements.With this lab, test common networking materials to become familiar with them and their resistancecharacteristics.
First learn to use the resistance setting on the multimeter. Note the continuity featureas small resistances are measured. The instructions provided are for the Fluke 110 and 12B. Othermeters will function in a similar way.1-3CCNA 1: Networking Basics v 3.1 - Lab 3.1.3Copyright 2003, Cisco Systems, Inc.Prior to starting the lab, the teacher or lab assistant should have one multimeter available for eachteam and various networking-related items for testing resistance.
Work in teams of two. Thefollowing resources will be required:•Fluke 110 Series or 12B multimeter (or equivalent)•1000 Ohm resistor•10,000 Ohm resistor•Pencil for creating graphite paths on paper•Category 5 jack•0.2m, or approximately 6 to 8 inch, section of Category 5 UTP solid cable•BNC terminated coaxial cable•Unconnected DB9 to RJ-45 adapter•Terminated Category 5 UTP patch cableStep 1 Select the Resistance Scale on the MultimeterFluke 110:Resistance Measurements: Move the rotary selector to the Omega symbol for Ohms (Ω) in order tomeasure resistance. Use the Range button to change the range of resistance to be measured basedon what resistance is expected.
The screen will show ohms(Ω), kilohms (KΩ= thousands of Ohms)or megohms (MΩ= millions of Ohms).Continuity Measurements: Move the rotary selector to the Beeper Sound symbol to the left of theOhms symbol. The Beeper Sound symbol is the setting to measure continuity. When there are lessthan 20 Ohms, the beep will sound. The beep means that the continuity is good. The continuitysetting is used when there is a need for a good path for electricity, but no need for the exact amountof resistance.Fluke 12B:Resistance Measurements: Move the rotary selector to the Omega symbol for Ohms (Ω).
TheOmega symbol is the setting to measure resistance. Press the button with the Ohms symbol on it toselect resistance mode instead of continuity. The screen should not show a diode symbol, a smallblack triangle pointing to a vertical bar. Use the Range button to change the range of resistance tobe measured based on what resistance is expected.Continuity Measurements: Move the rotary selector to the Omega symbol for Ohms (Ω).
TheOmega symbol is the setting to measure resistance. Press the button with the Ohms symbol on it toselect continuity mode. The screen will show a diode symbol, a small black triangle pointing to avertical bar. A diode is an electronic device that either passes or blocks electrical current. Whenthere is good continuity the beep will sound. Good continuity means low resistance.
The continuitysetting is used when there is a need for a good path for electricity, but no need for the exact amountof resistance.Step 2Check the following resistances. Turn the meter off when finished or the battery will drain.Item to MeasureSet Selector andRange Scale toResistance Reading1000 Ω Resistor10 kΩ Resistor2-3CCNA 1: Networking Basics v 3.1 - Lab 3.1.3Copyright 2003, Cisco Systems, Inc.Graphite marking from apencil on a piece of paperCategory 5 jack0.2 m section of Category 5UTP solid cableTouch red and black probecontacts togetherA human body (touch thetips of the probes with thefingers)BNC terminated coaxialcableUnconnected DB9 toRJ-45 adapterTerminated Category 5 UTPpatch cableReflectionWhat purpose might the multimeter serve in maintaining and troubleshooting a computer network?___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________3-3CCNA 1: Networking Basics v 3.1 - Lab 3.1.3Copyright 2003, Cisco Systems, Inc.Lab 3.1.5 Series CircuitsObjective•Build series circuits.•Explore the basic properties of series circuits.BackgroundOne of the basic concepts in electronics is a circuit.
A Circuit is a continuous loop through whichelectrons flow. Throughout networking there are references to ground loop circuit, circuit versuspacket switching, and virtual circuits, in addition to all the real circuits formed by networking mediaand networking devices. One of the fundamental electrical circuits is the series circuit.
Mostnetworking devices and networks are built from very complex circuits that are beyond the scope ofthe lessons included in this course. However, the process of building some series circuits will helpwith the terminology and concepts of networking. This lab also helps increase the overallunderstanding of some of the basic electrical circuit building blocks.Prior to starting the lab, the teacher or lab assistant should have one multimeter available for eachteam of students and various items to create circuits. Work in teams of two. The following resourceswill be required:1-3•Fluke 110, 12B or equivalent multimeter•Light switch•Wire cutters or wire stripper•Copper wire•Two 6v light bulbs with bulb bases or LEDs with resistors•6v lantern batteryCCNA 1: Networking Basics v 3.1 - Lab 3.1.5Copyright 2003, Cisco Systems, Inc.Step 1 Measure the Resistances of all devicesMeasure the resistances of all devices and components, except the lantern battery.
![](https://s.studizba.com/z.php?f=/templates/si/i/noavatar.png&w=100&h=100&t=1"){kind=avatar}
