Transcript Lecture 8

Admin:
Mid-term date set to Friday, March 20th.
• Assignments:
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Second graded assignment is posted
Make time for it – it’s a bit tougher than the first one
Due Monday March 2nd
Use the hints.
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email, the discussion TAs and their office hours and emails.
• My next office hours are tomorrow, 2pm – 3pm SHL 222
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Today
• Finishing up combination rules
• Kirchoff’’s laws, part 1
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Circuit analysis method 1:
Apply element combination rules
Series resistors
Parallel resistors
Series voltage sources
Parallel current sources
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An example using the current divider rule
Circuit analysis method 1:
Example
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1/REQ
Does it make sense?
I2 flows through lower resistance than I3, so I2>I3
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Current divider rule !!
1/R
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Kirchhoff’s Rules
Some circuits cannot be broken down into
series and parallel connections. For these
circuits we use Kirchhoff’s rules.
1824-1887
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Kirchhoff’s Rules
Junction rule (Kirchhoff’s current law):
The sum of currents entering a junction
equals the sum of the currents leaving it.
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Kirchhoff’s Rules
Loop rule (Kirchhoff’s
Voltage Law):
The sum of the
changes in potential
around a closed loop
is zero.
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