Alternate plus and minus

Cecil's Columns/Staff Reports
1

I think that Cecil missed answering Brad McKown’s question by a bit. While the “Batteries 101” was correct and instructive, Brad’s question was why the batteries are alternated. Cecil answer the electrical answer to this question (because you need more voltage) but there is also a mechanical answer (being an Electrical Engineer, I love to blame things on Mechanical Engineers).

So in an electronic battery powered gizmo such as a TV remote you typically need to put the batteries head to tail (in series) to increase the voltage (two times 1.5VDC is usually the case). Exit the EE whose job is done specifying the voltage needed and enter the ME.

How does the ME mount the batteries to give the EE the voltage he needs? If he puts the batteries in the holder in the opposite way (that Brad is asking about) then the ME can run a very short wire between the + of one battery and the - of the other (to complete the series circuit). Then he runs two short wires into the gizmo to supply power, one from the + of one battery and one from the - of the other. Here is a (terrible) diagram.

 -------> to device

/
(+) (-) ------> to device

| | | |
| | | |
| | | |
| | | |

(-) — (+)

But if the ME were to have both batteries side by side facing the same way, then he would have to run a longer wire from the + of one battery to the - of the other (to complete the series circuit). Then he would have to run two longer wires into the gizmo, one from the + of one battery and one from the - of the other.

 ------------> to device

/
(+) – (+) —> to device
---- / ---- /
| | | | | |
| | | | | |
| | | | | |
| | | | | |
---- / ---- /
(-) – (-) —
Maybe these few longer wires doesn’t mean much to Brad but it does make the device slightly more expensive (both extra wire and extra assembly). If compounded by thousands of devices, this can really add up. In the world of commerce, cheaper is always “better”.

Thanks, John

2

CEMX86SD, when you start a thread, it’s helpful to other readers if you provide a link to the column (in this case, the staff report) that you’re commenting on. Helps keep us all on the same page, and saves search time and avoids some confusion. In this case, I presume you mean: http://www.straightdope.com/columns/read/2951/
… which is not a column by Cecil but a staff report by Rico.

One might also note that there is already another thread on this topic: Alternating batteries - Cecil's Columns/Staff Reports - Straight Dope Message Board

3

CEMX86SD said:

Rico did address the question, here:

And then he includes a much better diagram.

By the way, ASCII art works better if you use “code” tags. That puts the content in courier font, which is uniform width letters. Lets you space things.

4

Here is the link to the original article. http://www.straightdope.com/columns/read/2951/

I have tried to see if I could make a better diagram with a bunch of text but the editor seems to condense multiple spaces into single spaces - really screws up my careful alignment. Forcing things into a mono-spaced font such as Courier didn’t help. If someone wants, I can post a link to a proper diagram to get my “long wire” point across.

Thanks, John

5

Like I said, try [noparse]


[/noparse] tags.

Like this

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Okay, not perfect, but it does break the forced space compression.  Use Preview and play with it.

Or just post a link