1. Complex Resistor CombinationsPg
Ch. 20-3

2. Complex Resistor Combinations
Rare to encounter only series or
only parallel in circuits
Generally both are combined

3. Complex Resistor Combinations
ex- homes
→ a fuse/circuit breaker in series with multiple outlets in parallel to each other
→ allows identical potential difference but safety from overload of current

4. Complex Resistor Combinations
In series with circuit:
fuse - small metallic strip that melts when current becomes too high.
→ Replacement necessary when melted
circuit breaker - device that triggers a switch to open circuit when current is too high
→ reset switch when opened
both are specially designed for specific amounts of current

5. Complex Resistor Combinations
→ To find Req for a complex circuit
1. Simplify circuit into groups of series and parallel resistors
2. Find Req for each group
Work backwards to find current in and potential difference an individual resistor or lamp or component

6. Complex Resistor Combinations
Steps for Finding Req in a Complex Circuit
1. Redraw the circuit as a group of resistors along one side of the circuit.
2. Identify components in series and calculate their Req
3. Identify components in parallel and calculate their Req
4. Repeat steps 2 and 3 until all resistors in circuit are reduced to a single Req
5. Redraw the circuit using the final Req connected to the original emf source.