Section 3 review
Most electrical circuits have more than one resistive component: Homes have many appliances, cars have two headlights, and so on. Resistors can be connected in series or in parallel. In a series circuit, each resistor carries the same amount of current but gets only a fraction of the total battery voltage. In a parallel circuit, each resistor “feels” the battery’s entire voltage but only carries a fraction of the total current. A parallel circuit will exhibit higher wattage (power) than a series circuit built from the same resistors. The total current in a series or parallel circuit can be calculated with Ohm’s law by using the equivalent resistance for that circuit. Read the text aloud
series circuit, equivalent resistance, parallel circuit, Kirchhoff’s current law, Kirchhoff’s voltage law, circuit breaker, kilowatt-hour (kWh)

V=IR
R= R 1 + R 2 + R 3 +
1 R = 1 R 1 + 1 R 2 + 1 R 3 +
P=IV

Review problems and questions

Circuits (A) through (D) for the next five questions
The following five questions pertain to the four circuits (A, B, C, and D) shown above.
  1. In which circuit do the three resistors have equal voltage drops but carry different current? Read the text aloud Show
  1. In which circuit do the three resistors carry equal current but have different voltage drops? Read the text aloud Show
  1. Which of the circuits has the lowest equivalent resistance? Read the text aloud Show
  1. Which of the circuits has the highest equivalent resistance? Read the text aloud Show
  1. Assume that Circuits A, B, C, and D have identical batteries and convert all of their power to thermal energy. Which of the four circuits will produce the most heat? Read the text aloud Show
  1. Compile a list of the major appliances in your home and the power that each consumes.
    1. How much total power does your list of appliances use if they are all running at once?
    2. How much total current do they use?
    3. Which appliances use the most power?
    Read the text aloud Show

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