Connecting batteries in series, as shown in Figure 1, means connecting them in line with each other so that there is but a single path for electrons to flow through them all. If you connect batteries so that the positive terminal of one battery connects to the negative of the other, you will find that their respective voltages add up.
Note: Any size batteries will work for this experiment, but using batteries of different voltages will make the results more interesting
Step 1: Connect the batteries in series by connecting the positive terminal of one battery to the negative terminal of the other, as illustrated in Figure 2. This creates a single path for the electrons to flow through.
Step 2: Measure the voltage across each individual battery and then measure the total voltage across both batteries, as illustrated in Figure 3.
Step 3: Try connecting batteries of different voltages in series (e.g., a 6 V and a 9 V battery). Record the total voltage.
Step 4: Next, reverse the terminal connections of one of the batteries, as shown in Figure 4, and again measure the total voltage. Compare this to the previous result.
Step 5: Take note of the polarity of the total voltage as indicated by the voltmeter and the test probe orientation. Remember, if the digital indication is a positive number, the red probe is positive, and the black probe is negative. If the indication is a negative number, the polarity is backward (red = negative, black = positive). Analog meters may not read correctly if reverse-connected as the needle may not be able to move in the opposite direction.
Step 6: Can you predict what the overall voltage polarity will be based on the polarities of the individual batteries and their respective voltage ratings?
Learn more about the fundamentals behind this project in the resources down below:
Video Tutorials and Lectures:
In Partnership with Geehy Semiconductor
by Duane Benson
by Robert Keim