Why do decade boxes go to 11?

[kfitch42]

In the recent vid I was a bit perplexed as to why the "decade" resistance box had 11 positions on each knob. From what I can tell this seems pretty common for all sorts of 'decade' boxes. Is there any practical reason for this? Do you really need/want multiple ways to construct the same resistance value?

[Excavatoree]

Because if you just have 10, you've got nowhere else to go.  Ours have that one extra.

Seriously, I imagine it's for convenience - if one is setting the thing for several values for some reason or another, having multiple options can reduce the number of switch changes.  If you're adjusting from 1,2,3... and need to get to 10, you can get there without moving your hand to another knob.  It's small, and one without the extra would work, but more is nicer.

[mikes]

When you're searching for the right value, you can move between 9 and 10 with one click. Otherwise, you'd have to go from 9 to 0 on one decade, and up 1 on the next. Of course, if you need to go even more, you need to do that, but having 10 on a decade allows for a quick and easy check before you commit to that large change. When searching for the right value, you often keep incrementing until you go 1 too far, and having a 10 makes that quicker.

Less significant is that lower decades usually handle more current, so you get a bit more range. Also, it extends the range of the box (e.g. 11,110 vs. 9,999), so nothing is wasted.

[oPossum]

Because 11 is one louder than 10

[ejeffrey]

Also, decade boxes are not necessarily monotonic.  1000 ohms could be less than 999 ohms, since different resistors are in use.  Alternately, there could be a large gap.  Overlapping ranges allows you to always have a small usable region where the box is monotonic and without large gaps.

[mikeselectricstuff]

Well they make fridges, so why not....

[4to20Milliamps]

I'm buying a Marshall fridge but only if it has a keg tap AND I can plug my guitar into it.


I won't give an answer........but I will give a clue:

http://en.wikipedia.org/wiki/E48_series#E_series

[cwalex]

Well they make fridges, so why not....

 

When I saw the thread title I was sooo hoping no one had made the jokes yet. I should have known better.