PHYS117B'02 : Lecture 11 and Lecture 12

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PHYS117B.02 Lecture 11 and Lecture 12

• EMF, Internal resistance, Power in electric
  circuit
• Resistors in series and in parallel. Kirchhoffs
  rules

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EMF
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Electric field and current inside a wire
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Open circuit with a source

• I 0
• V e

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A source in a complete circuit

• I ?
• V ?

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A source with a short circuit

• I ?
• V ?

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Potential graph in a circuit
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Power in Electric circuit
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Resistors in series

• Same current goes through R1 , R2 ,R3

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Resistors in parallel

• Same potential difference on all resistors

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Combinations of 3 resistors

• Req ?

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Example of a complex circuit which can be reduced
using equivalent resistance

• Done on the blackboard

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Kirchhoffs rules
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Sign conventions
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Single loop circuit Example 26.3
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More complex example 26.4
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Bridge circuit ( ex 26.6 cant be reduced to Req