Force and motion
Force and Motion
Two batteries in series
There are four different ways you can attach two batteries together. You can test each combination using a multimeter. Here are the four combinations, showing how you attach the red and black probes to each one:
A. Red to + / - to + / - to Black
B. Red to - / + to + / - to Balck
C. Red to + / - to - / + to Black
D. Red to - / + to - / + to Black
All four connections are shown in the video above and the diagram below. This experiment shows you what happens in each case, and why only one of the connections will give a total voltage of + 6 volts. Can you guess which one? what voltage reading do you expect in each case?
Answers:
A. Here the two batteries have the same polarity, +/-, so voltages add up, giving (+3) + (+3) = +6 Volts.
B. The two batteries are connected with opposite polarities -/+ follwed by +/-, so the volatges cancel. The resulting voltage is zero, because +3 + (-3) = 0 Volts.
C. As in B, the batteries are again connected with opposite polarities +/- followed by -/+, but in the reverse order from B. Again, the voltages cancel and the total voltage is zero: (-3) + (+3) = 0 Volts.
D. This case is like A, except that both batteries are reversed. Both batteries have the same polarity, this time -/+. The total voltage is (-3) + (-3) = -6 Volts.