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Series & Parallel Circuits

Mahi Tuatahi

A circuit has current $1.2A$ and voltage of 12V and has a single bulb.

  1. Draw the circuit and indicate current and conventional current directions.
  2. How many Coulombs of electrical charge flow through a point in every second?
  3. How much energy is used by the bulb in 5 seconds?
  4. What is the resistance of the bulb?

Series Circuits


Parallel Circuits


Constructing Circuits

Use the PhET simulation to build these circuits:

  1. Create a series circuit with a bulb and a switch
  2. Create a parallel circuit with a bulb and a switch on each path, and one switch that controls the whole circuit.
  3. Measure the resistance of the circuit in PhET when you add resistors to the different circuit and try make a rule for what happens.

Resistance in Circuits


Calculating Resistance

In series we can use this equation:

\begin{aligned} & R_{T} = R_{1} + R_{2} + R_{3} + … \end{aligned}

In parallel we can use this equation:

\begin{aligned} & \frac{1}{R_{t}} = \frac{1}{R_{1}} + \frac{1}{R_{2}} + \frac{1}{R_{3}} + … \end{aligned}


Question 1


Question 2


Calculate the values for each voltmeter, ammeter, as well as the total resistance of the circuit.

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