Resistance is futile

ResistanceIsFutileNo, this is not about seven of nine, the only attractive Borg I know of. This post from Brick started all of this. Before we knew it, local repeaters were buzzing with endless (mainly humorous) discussions about zero ohm resistors. It was impossible to miss the disturbance in the Force when these wolf packs of hams were diving into the theory.

I actually located some shops selling these things, and e-mailed them if they could offer a version with 1% tolerance rings printed on them. Some sellers had a good laugh, some didn’t know what to say.

But, let’s start with correcting the title of this post. Resistance isn’t futile, it is voltage divided by current. We call it Ohm’s law.

OhmsLaw.svgI never could fault this law, until I ran into those damned zero ohm resistors. Let’s assume that we don’t know the current, but we do know the voltage and the resistance. Piece of cake, you would say, just divide the voltage by the resistance. OK, fine, now insert a zero ohm resistor. From that point on you can’t avoid dividing by zero.

This is an interesting situation: technically you can’t divide by zero, because the outcome will always be undefined. In Dutch: “Delen door nul is flauwekul.”

This must be the reason for many transceivers to fail when 0Ω resistors are part of the design. I know of hams who ignore these dangers completely and solder these things in to perform a MARS/CAP modification. The poor bastards. This post, based on scientifically proved facts and written by a trustworthy radio amateur, should be enough to scare them off.

5 comments on “Resistance is futile

  1. More impressive than 0 ohm resistors are the results that can be achieved with a fractional ohm resistor. A .1 ohm resistor in the right place can increase radio performance by up to 3dB.

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