Resistor colour codes [no longer Re: Micropolis]

[Tony Duell]

> 
> >> But, what is the resistor color code for negative ohms?
> > A pigment that reflects only infrared?
> 
> Outside the 2..7 range, there is no spectral order.  (Black, brown,
> grey, and white are not part of the spectrum in the usual sense.)
> Still, the idea makes some sense.  But most floating-point formts are
> sign-magnitude, and I see no reason this would be different - perhaps
> the body should be a different colour?

That's what I would have suggested, except what do you do about 
body-tip-spot coded -ve resistors :-) :-) :-)

Some old Tekky 'scopes have colour-coded wires for the main power supply 
rails. The 2 stripes give the 2 post significant digits of the supply 
voltage (it is assumed there's not a 15V and 150V supply in the same 
instrument, for example), the base colour is, IIRC, white for a +ve rail 
and black for a -ve one. Soe there is some precedent for changing the 
background colpur for -ve resistors :-)

-tony