Investigation 17B: Voltage and batteries

Essential questionsHow do you connect batteries to increase their total voltage?
When Alessandro Volta invented the first electric battery, he connected several individual battery cells together to create a more powerful composite battery. How did he connect them? In this investigation you will connect two batteries together and determine how to make the largest combined voltage.

There are two basic ways to connect electrical components together. In a series connection, the two components are connected one after another. In a parallel connection, the components are connected side-by-side—with the “tops” connected together and the “bottoms” connected together.
Part 1: Connecting batteries in parallel

Part 1: Connecting batteries in parallel
  1. Open the experiment file 17B_VoltageAndBatteries, and then power-on the Voltage Sensor and connect it wirelessly to your software.
  2. Connect the two batteries in parallel: connect their positive terminals to each other and connect their negative terminals to each other.
  3. Use the voltage sensor to measure the voltage across the two batteries connected in parallel.
  1. Read the voltage rating on the side of each battery. How does the printed voltage compare with what you measured?
  2. How does the voltage of the two batteries connected in parallel compare with the voltage of either battery measured separately? Explain your answer.
Part 2: Connecting batteries in series

Part 2: Connecting batteries in series
  1. Connect the two batteries in series: connect the negative terminal of one battery to the positive terminal of the other battery.
  2. Using the voltage sensor, measure the voltage across the two batteries connected in series.
  1. How does the voltage of the two batteries connected in series compare with the voltage of either battery measured separately? Explain your answer.
  2. Compare the series and parallel circuits. Which would you use to create the largest voltage?
  3. Which circuit design would you expect to find in a flashlight or other electrical device?
  4. Open up the battery compartment of a flashlight and look at any visible wires to see how it is connected. Can you tell if the batteries are connected in series or parallel?

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