Could somebody please explain how batteries in series increase voltage? For example: An example of batteries in series

For example, here, the left most battery increases the voltage from 0v to 12v, then the middle battery increases the 12v to 24v and the right most increases the 24v to 36v. How does the middle battery actually increase the voltage coming in from the from the left of it by 12?

I've looked up how batteries work online, all the animations and videos show how current flows from the negative terminal of the battery to the positive terminal of the same battery.

How a single battery works

Okay, but how does this arrangement work when two batteries are next to each other? And why does this increase voltage, but not current? Surely if I add another battery to a circuit, and the voltage increases (I don't know how it increases), and the resistance remains the same, then current has to increase!

And while were here, could you also explain why in parallel, the current increases?

(unfortunately I cannot post a 3rd link, which would have been of a parallel circuit, but google imaging 'batteries in parallel' should show an image like the first one in my post)

Does it have something to do with kirchhoff's current law? The current entering and leaving a node must be 0?

Thanks guys!

  • \$\begingroup\$ This is too trivial, series Voltages add. \$\endgroup\$ Commented Jan 14, 2017 at 0:02
  • \$\begingroup\$ Yes i know that, but I'm trying to understand why. The way I'm picturing it, if the electrons are going from the negative terminal of one battery, to the positive terminal of the other, shouldn't they just remain there? \$\endgroup\$
    – Physco111
    Commented Jan 14, 2017 at 0:04
  • \$\begingroup\$ just for you falstad.com/circuit/… \$\endgroup\$ Commented Jan 14, 2017 at 0:11
  • \$\begingroup\$ snag.gy/F9ClWt.jpg \$\endgroup\$
    – Physco111
    Commented Jan 14, 2017 at 0:35
  • \$\begingroup\$ Thanks but, this is where I'm getting confused (hopefully you can see the image) But if you look at the gif, as the battery 'loses charge' the electrons are remaining on the positive terminal, so if two are next to each other, should the electrons remain in the positive terminal. Obviously it doesn't, but i just want to know why the way I'm picturing it is wrong, and what the better way to picture it is. \$\endgroup\$
    – Physco111
    Commented Jan 14, 2017 at 0:38

2 Answers 2


What a long question to ask for a simple answer. It's easy when you think about it.

Imagine each battery is a step on a staircase. Each step takes you higher than the last, each step the same amount up compared with the previous step.

If we imagine some fairly steep steps, they might each be 12 inches high.

When you have gone up 3 steps, you are 36 inches (volts!) higher than the beginning, each step having added 12 inches.

If the staircase is narrow, then building another next to it will allow more people to use it (current increases).

Electricity 'flows' from high to low potential, just as a ball will only roll down steps.

Good luck taking your first steps in electronics. Might I suggest you consider buying a book on the subject though: https://www.amazon.com/Electronics-Dummies-Cathleen-Shamieh/dp/0470286970 is a good start.

  • \$\begingroup\$ Thank you, I do appreciate your reply, but I think people are misunderstanding the question. This will probably be the closest I'll get to an answer. Maybe I'm just trying to understand something that I'll just have to accept. \$\endgroup\$
    – Physco111
    Commented Jan 14, 2017 at 1:44
  • 1
    \$\begingroup\$ @Physco111 I suspect that you might have a wrong idea on the nature of voltage. If so, then no explanation will work for you. First you'd have to debunk all the misconceptions about voltage. And then replace with the correct concepts. For example, a wire cannot have a voltage. The left-hand battery does not feed a voltage to the right-hand battery via a wire. That's not at all how voltage actually works ...so we cannot answer your question as stated. This helped me: Chabay/Sherwood 2006, Circuits and Stat Elec physics matterandinteractions.org/wp-content/uploads/2016/07/… \$\endgroup\$
    – wbeaty
    Commented Sep 12, 2019 at 7:36
  • \$\begingroup\$ @Physco111 beginning lesson: ignore batteries, replace them with parallel-plate capacitors. (Fundamentally, a battery is a self-charging capacitor. Also, most questions about voltage will usually involve capacitors, zero currents, and no load resistors.) Take two identical capacitors, briefly use a charging source to put 1,000V across each one, then connect them in series-stack, plus-to-minus. What were the inital potentials on each capacitor plate wrt the distant ground? When the terminals are touched together, why does 2,000V instantly appear across the ends of the stack? \$\endgroup\$
    – wbeaty
    Commented Sep 12, 2019 at 7:48

The GIF you posted has to do with the chemical reaction that happens when you discharge a battery.

Current flows from the Anode (positive) to the Cathode (negative) in relation to a series circuit.

That being said, if you think about it in a different way; The current does move THROUGH a battery from the negative to positive but it’s important to not mix up the schools of thought.

Notice how from the left of your first picture it starts:

Negative -> Positive -> Negative -> Positive -> Negative -> Positive

Regarding first picture, you have to think about current flow going in a clockwise direction starting at the negative of the first battery and going all the way through to the positive of the last battery, then through the “load” (motor, light bulb, etc.), back to the negative terminal and that is the DC series circuit.


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