A voltmeter is used to determine the voltage acrossa resistive element in the circuit of Figure P2.77. The instrument is modeled by an ideal voltmeter in parallel with a
a.
b.
c.
d.
(a)
The voltage across R4 with and without voltmeter for the given value.
Answer to Problem 2.77HP
Without the voltmeter
With the voltmeter:
Explanation of Solution
Given information:
The given circuit is shown below.
Calculation:
Assuming that voltmeter is ideal in parallel with 120-ohm resister.
First develop an expression for VR4 in terms of R4 ,using current division
Therefore,
Hence,without the voltmeter
Now find the voltage drop across
With the voltmeter:
(b)
The voltage across R4 with and without voltmeter for the given value.
Answer to Problem 2.77HP
Without the voltmeter
With the voltmeter:
Explanation of Solution
The given circuit is shown below.
Calculation:
Assuming that voltmeter is ideal in parallel with 120-ohm resister.
First develop an expression for VR4 in terms of R4, using current division.
Therefore,
Hence, without the voltmeter
Now, it is must find that the voltage drop across
With the voltmeter:
(c)
The voltage across R4 with and without voltmeter for the given value.
Answer to Problem 2.77HP
Without the voltmeter
With the voltmeter:
Explanation of Solution
The given circuit is shown below.
Calculation:
Assuming that voltmeter is ideal in parallel with 120-ohm resister.
First develop an expression for VR4 in terms of R4, using current division.
Therefore,
Hence, without the voltmeter
Now, it is must find that the voltage drop across
With the voltmeter:
(d)
The voltage across R4 with and without voltmeter for the given value.
Answer to Problem 2.77HP
Without the voltmeter
With the voltmeter:
Explanation of Solution
The given circuit is shown below.
Calculation:
Assuming that voltmeter is ideal in parallel with 120-ohm resister.
First develop an expression for VR4 in terms of R4 ,using current division
Therefore
Hence without the voltmeter
Now it is must find that the voltage drop across
With the voltmeter:
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Chapter 2 Solutions
Principles and Applications of Electrical Engineering
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