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Chapter 6
Digital Measurements
1 ) Show True or False :1- The accuracy of Analog Multimeter is better then DMM .
(
)
2- The DMM able to select suitable range of input automatically
(
)
3- The main circuit in DMM is A/D converter.
(
)
4- In DMM all measured input is converted to current and then measured (
)
5- The DMM can measure ac and dc current .
)
(
6- In The DMM, the accuracy of AC measurements is better than DC measurements .
7 - The accuracy of ……………. is better than Analog Multimeter .
( Complete )
8 - Range selection is done ………………….
Answer the following question :
2 ) What are the advantages of Digital Multimeter ( DMM ) over Analog
Multimeter?
a) ………………………………………………
b) ……………………………………………..
c) ……………………………………………….
d) ………………………………………………
e) ……………………………………………..
3 ) Mode of Operation:
a) ………………………………………..
b) ……………………………………….
c) ………………………………………..
4 ) Main Sources of Errors
a)
……………………………………..
b)
…………………………………….
c)
………………………………………
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Switching Section
4 – The block diagram shown below represents the DMM :
Complete the main parts
Block
Name
1
2
3
4
5
5 ) Match the Following :
Block
(Stage)
1
Name
Function
Resistance to voltage
Converter
A resistive network to provide a scaling voltage
represents the measured resistance. ]
Voltage divider
The voltage divider is a resistive network to define
automatically the suitable range of measured
voltage.
3
Precision resistor network
to convert I to V
[ A high accurate resistive network,convert the input
( AC / or DC ) current to voltage drop.]
4
AC to DC converter.(
Rectifier circuit )
Convert the AC voltage to DC voltage .
5
Analog to Digital converter
( A / D converter )
Convert the analog signal to digital format to be fed
to display window.
2
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Switching Section
6 ) Complete the BCD and display unit of a DMM to display the decimal
value = 56 on the digital screen.
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Switching Section