Lecture 5 Circuit Reduction

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Lecture 5Circuit Reduction

• ECE 205
• Prof. Ali Keyhani

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Circuit Reduction

• The concepts of series/parallel equivalence,
  voltage/current division and source
  transformation studied so far, can be used to
  simplify the analysis of complex circuits such as
  Ladder Circuits
• With circuit reduction the circuit is simplified
  by eliminating certain nodes and elements

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Example 1

• Find the output voltage vo and input current is.
• Solution The approach is to combine to parallel
  resistors and use voltage division to find the
  output voltage.
• The input current is found by finding the
  equivalent resistance of the circuit and then
  using Ohms law.

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Example 2

• Reduce the circuit between terminals a and b to a
  single resistance.
• Solution

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Example 3

• Determine the voltage across and the current
  through, three resistances of 5?, 10 ?, and 20 ?,
  all connected in parallel an across a100V source.
• Find the current and power drawn from the source.
• Solution

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Example 4

• Find the output voltage vo and the input current
  is in the given ladder circuit.
• Solution
• The voltage source is transformed to a current
• Source by breaking the circuit into to parts.(Fig
  b)
• Note The input current is not the current source
• vs/R and is found by current division rule