Electrical Workshop Module 4:

Study of Measurement &Test Equipment

(2-weeks)

Institute Of Applied TechnologyATE 1012Grade 10

Eng. Rose Hasan

Eng. Rose Hasan

Module Objectives

Be familiar with the usage of Multi-meters, Oscilloscopes and Function Generators

Perform Measurements of electrical quantities using measuring instruments

Test diodes and connectivity

Module Contents

Introduction Multimeter

Voltage Measurement Current Measurement Resistance Measurement

Diode Testing Continuity Test Function Generator Oscilloscope Practical Tasks

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Introduaction Measuring and Test Equipment are used to:

measure electrical quantities test electrical components generate different types of signals to test the

response of the circuit to that signal. Measuring and test equipment can be used

to: troubleshoot electrical problems in many

industrial and household devices such as batteries, lamps, motor controls and wiring systems

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Eng. Rose Hasan

Measurement & test equipment functions

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Multimeters

Purpose: A multi-meter is an electronic measuring instrument that combines several functions in one unit. It is used to: measure voltage, current and resistance

and to test diodes and connectivity

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Multimeter Functions

MultimeterTypes: There are two

types of multimeters: analog & digital

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Multimeter circuit symbols

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Digital Multimeter Measurements: Voltage Measurements

Voltage Measurement (Voltmeter): To measure the DC voltage across electrical components in a circuit, follow these steps: Select on the digital multi-

meter's setting switch on the largest voltage range.

Connect the positive (RED) (+) lead to the part of the circuit that is connected to the positive (+) side of the supply (battery).

Digital Multimeter Measurements

Connect the negative (BLACK) (-) lead to the part of the circuit that is connected to the negative (-) side of the supply (battery).

Switch on the multi-meter by pressing "POWER" button. Then select the best range that will give you the most accurate results.

Record the reading and the unit that are displayed in the multimeter's display.

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http://serc.carleton.edu/sp/compadre/interactive/examples/19095.htmlhttp://www.physics-chemistry-interactive-flash-animation.com/electricity_electromagnetism_interactive/multimeter.htm

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Practical Tasks: Activity1: Battery Tester Items Required:

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Battery Tester, Steps:

Measure the voltage across the batteries using a multi-meter:

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Results:

Record your readings on the following table. The true value is the value written on the battery

Results:

3. Compare the measured value with the true value of the voltage written in the battery. Is the measured value close to the real value? If no, state why? ______________________________________

4. You can test a battery using Multi-meter by: (a) Voltage measurement (b) Connectivity test (c) Diode Test

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Digital Multimeter Measurements: Current Measurements

Current Measurements : To measure the DC current flowing in electrical circuit, follow these steps: Plug the BLACK (-) probe into the

COM input jack and the RED (+) probe into the mA or A input jack.

Adjust the digital multi-meter for current measurements .

Switch off the power in the circuit.Eng. Rose Hasan

Eng. Rose Hasan

Digital Multimeter Measurements: Current Measurements

Break the circuit between elements where the current to be measured.

Insert the probes of the multi-meter in the place where do you break the circuit.

Switch on the multi-meter. Select the best range that will give you

the most accurate results. Record the reading and the unit that are

displayed in the multi-meter's display

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Steps to measure current

Digital Multimeter Measurements: Resistance Measurements

Resistance Measurements (Ohmmeter): To measure the resistance of a resistor, follow these steps: Turn Off the power to the circuit and

remove the components to be tested. Select on the digital multi-meter's

setting switch on the lowest resistance range.

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Resistance measurement using multimeter

Plug the BLACK (-) probe into the COM input jack and the RED (+) probe into the Ώ input jack.

Connect the probe tips across the component you want to measure its resistance

Switch on the multi-meter and select the best range that will give you the most accurate results.

Record the reading and the unit that are displayed in the multimeter's display.

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Activity 2: Resistance Measurements

Items Required:

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Steps: Measure the resistance across different

resistors using a multimeter and color code

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Results:

2. Record your readings on the following table

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Results:

3. Compare the value of resistance measured by the multi-meter and color code. Are the values close to each other?

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Activity 3: Voltage and current Measurements Items Required:

Resistors (200Ώ), multi-meters Electricity & Electronics Constructor,

EEC470 Basic Electricity and Electronics Kit

EEC471-2 Power supply unit

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Steps: Construct the simple circuit shown below. Use 200 Ώ

resistor values.

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Steps:

Connect the multi-meter to the power supply.

Make sure that the variable dc control knob is fully counter clockwise, and then switch on the power supply.

Increase the applied voltage in 2 V steps from 0 V up to 5 V.

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Results:

At each step measure the current flowing in the resistor. Record your reading in the following table:

Resistance Measurements (Ohmmeter):

To measure the resistance of a resistor, follow these steps: Turn Off the power to the circuit and remove

the components to be tested. Select on the digital multi-meter's

setting switch on the lowest resistance range.

Plug the BLACK (-) probe into the COM input jack and the RED (+) probe into the Ώ input jack.

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Steps:

Connect the probe tips across the component you want to measure its resistance

Switch on the multi-meter and select the best range that will give you the most accurate results.

Record the reading and the unit that are displayed in the multimeter's display.

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Diode Testing: To test if the diode is functioning or not,

follow these steps: Adjust the digital Multi-meter for diode-

testing . Connect the positive lead (Red) (+) to the

anode (A(+)) and connect the negative lead (BLACK) (-) to the cathode (K(-))

Switch on the multi-meter. For a diode in a good condition the reading will be ≤ 300 mV for Ge diode and ≤ 700 mV for Si diode.

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Results:

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Steps & Results: Now connect the (RED) (+) lead to the

(K(-)) and (BLACK) (-) lead to the (A(+)) For a diode in a good condition the reading will

be for both types.

Continuity Test:

To test if two points are electrically connected, follow these steps: Turn Off the power to the circuit Adjust the digital Multi-meter for

continuity-testing and Switch on the multi-meter.

When the probes aren't touching, the display shows "1“.

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Continuity Test:

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Continuity Test: When you touch

the tips of the probes together, the display changes to a three digit mode. The multi-meter will also emit a beep.

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Diode Activity

http://www.wisc-online.com/objects/ViewObject.aspx?ID=AMT2104

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Function Generator

Purpose: Function generator is used to produce different waveform such as: Sine Square Triangular

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Function Generator (Purpose) It is used to test and examine the

response of an electrical circuit to that signal. (i.e. the motor response to a square or

triangular signal).

Function Generator

Main Control Keys: The function generator has many control keys to control the: waveform shape amplitude Frequency

http://www.physics-chemistry-interactive-flash-animation.com/electricity_interactive.htm

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The following table shows function generator main keys and their usage.

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Oscilloscope

Purpose: Oscilloscope is a device that is used to display different waveforms simultaneously (i.e the input and output of an amplifier).

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Main Control Keys: Oscilloscope has many control keys to scale the:

amplitude periods of the displayed waveform.

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Function Generator

The following table shows some oscilloscope main keys and their usage.

Activity 4: Oscilloscope and function generators Items Required:

Function Generator Oscilloscope speaker

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Measuring Voltage & Time period

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What is the name of this testing equipment ?

Oscilloscope

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Oscilloscope Screen ( Axis)

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http://physics-zone.com/lab_oscfunctiongen.html

Oscilloscope Lab Worksheet

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Lab ActivitiesSteps:1. Connect the function generator and

oscilloscope as shown below.

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Steps2. Set the function generator to give 5v pk and 1 kHz.3. Select channel A on the oscilloscope. Set the volt/division

scale to 5v and time/division to 250 us (μs).4. Amplitude Measurement: measure the pk-pk voltage

of the waveform as seen in the following:

Cont. Steps

Volt/division scale = -----------------------------

No. of divisions = -----------------------------

Pk-Pk voltage = -----------------------------5. Period Measurements: measure

the period of the waveforms seen in figure

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Eng. Rose Hasan

Cont. Steps

Time/division scale = -----------------------------

No. of divisions = -----------------------------

T (Period) = -----------------------------

Future Plan

Be prepared for a Quiz next Class in module #4.

Do Homeworks 1 & 2 (From my Wiki).

Next Class: Start with Module #5

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