INC 111 Basic Circuit Analysis

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INC 111 Basic Circuit Analysis

• Week 6
• Other Techniques

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Special Techniques

• Superposition Theorem
• Thevenins Theorem
• Nortons Theorem
• Source Transformation

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Source Transformation
When we do not need to know the current and the
voltage inside the box, we can interchange the
circuit inside without affecting other parts in
the circuit.
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Example
Use source transformation to find Ix
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Maximum Power Theorem
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High RL high voltage, low current Low RL high
current, low voltage
ISC
V
VOC
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Maximum Power Theorem
From Thevenin or Norton equivalent circuit, the
RL that gives the maximum power is RL that
equals Rth.
RL that gives the maximum power is RL Rth
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Proof
where
Substitute in the equation
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Find the first derivative. Let it equal zero to
find critical points.
Therefore, RL Rth is the point that yields
maximum power
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Example
Find RL that gives the maximum power and find
that power.
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Thevenins equivalent circuit
RL that gives the maximum power is 13.2?
Maximum Power is
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Voltage Sources in Real World
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I
V
V
Real Voltage Source
Ideal Voltage Source
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Current Sources in Real World
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I
V
V
Real Current Source
Ideal Current Source