I used to joke about why there's no tolerance band
on 'zero ohm jumpers'
(short-circuit shunts built with the same package outline as a resistor,
There a plenty of jokles about 20% 0-ohm jumoers being cheaper than 10%
ones :-).
I believe the actual spec for a zero ohm jumper does give a maximum
resistance if it's installed with a particular lead length. Which makes
sense.
often used in instances where a board-stuffing machine
needs to put
*something* in a hole where a resistor might have gone. Usually they
have one black band in place of the regular 'resistance value' bands).
Zero ohm jumpers are a relatively modern idea. I've seen boards in
classic computers (some old HP stuff, for example) where options were
selected by soldered-in low-value resistors (10 ohm, 22 ohm, etc). A
shorting link would have been fine, I guess they used the resistors for
the same reason that zero-ohm jumpers are now used -- automatic
board-stuffing machines can insert them. Zero ohm jumpers didn't exist
back then.
-tony