2. Be familiar with the usage of Multi-meters,
Oscilloscopes and Function Generators
Perform Measurements of electrical
quantities using measuring instruments
Test diodes and connectivity
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3. Introduction
Multimeter
Voltage Measurement
Current Measurement
Resistance Measurement
Diode Testing
Continuity Test
Function Generator
Oscilloscope
Practical Tasks
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4. 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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6. 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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10. 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).
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11. 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.
http://serc.carleton.edu/sp/compadre/interactive/examples/19095.ht
ml
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13. Measure the voltage across the batteries
using a multi-meter:
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14. Record your readings on the following table.
The true value is the value written on the
battery
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15. 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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16. 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.
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17. 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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19. 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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20. 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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23. Measure the resistance across different
resistors using a multimeter and color code
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24. 2. Record your readings on the following
table
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25. 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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26. Items Required:
Resistors (200Ώ), multi-meters
Electricity & Electronics Constructor, EEC470
Basic Electricity and Electronics Kit EEC471-2
Power supply unit
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27. Construct the simple circuit shown below. Use 200 Ώ
resistor values.
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28. 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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29. At each step measure the current flowing in the
resistor. Record your reading in the following
table:
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30. 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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31. 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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32. 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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34. 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.
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35. 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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37. 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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38. Purpose: Function generator
is used to produce different
waveform such as:
Sine
Square
Triangular
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39. 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).
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40. Main Control Keys: The function generator
has many control keys to control the:
waveform shape
amplitude
frequency
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41. The following table shows function generator
main keys and their usage.
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42. 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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43. Main Control Keys: Oscilloscope has many
control keys to scale the:
amplitude
periods of the displayed waveform.
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44. The following table shows some oscilloscope
main keys and their usage.
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45. Items Required:
Function Generator
Oscilloscope
speaker
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50. 1. Connect the function generator and
oscilloscope as shown below.
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51. 2. 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:
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52. 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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53. Time/division scale = -----------------------------
No. of divisions = -----------------------------
T (Period) = -----------------------------
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54. 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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