Basic_Electrical_Engineering_4th_edition
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ELECTRICAL ENGINEERING |
Current supplied by the battery |
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10 |
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15 |
A |
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4 + 4/3 |
16 |
8 |
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Current through 2 Q resistor |
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15 |
4 |
5 |
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- X |
- = |
- A |
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8 |
6 |
4 |
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Total current through |
AB 5 + |
4 |
4 A |
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is |
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5 |
25 |
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- = |
- |
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The Norton's equivalent circuit, therefore is |
2 Q |
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4 |
A |
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2 Q |
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25 |
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Fig. E 2.1 5.2 |
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through |
branch is |
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Therefore, current |
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425ABx 2=1 |
S25 = 3.125 A |
2.9 MAXIMUM POWER TRANSFER THEOREM
Sometimes in electronics circuits it is desirable to transfer maximum power through a source to a load e.g. impedance matching is carried out in a loud speaker so that maximum sound could be heard. However in power system maximum power transfer is never tried as huge amount of power in terms ofMW are transferred from source to the load and the efficiency of transfer is 50% as will be seen shortly ifpower transferred is based on maximum power trans fer criterion. Also under this, the terminal voltage becomes half of the source voltage and hence this results in poor voltage regulation, therefore, maximum power transfer criterion is never considered in power system.
We will consider the theorem both for d.c. and a.c. circuits. d.c. circuits :
Fig. 2.10 Maximum power transfer-d.c. circuit.