SV: Re: SV: Re: SV: Re: [sdiy] Compensating PTC and NTC resistors

[René Schmitz]

Hi Dave,

Dave Manley schrieb:
> Thanks very much for the detailed explanation.  All is perfect except a 
> little typo - an addition instead of a subtraction in the second case. 
> This has been an informative thread even with the smog that sometimes 
> fills the air ;-)
> 
> -Dave

>> (1000ohm * 3900ppmK^-1 + 163ohm * 100ppmK^-1) / (1000ohm + 163ohm)
>> = 3367ppmK^-1
>>
>> (1000ohm * 3900ppmK^-1 + 163ohm * 100ppmK^-1) / (1000ohm + 163ohm)
> 
> -------------------------^

Sure, that's got to be:
(1000ohm * 3900ppmK^-1 + 163ohm * -100ppmK^-1) / (1000ohm + 163ohm)

that way it shows where that minus was coming from.

Cheers,
  René