[sdiy] Compensating PTC and NTC resistors

[René Schmitz]

Hi Paul and all,

Paul Perry schrieb:
> Using a metal film resistor to tweak the coefficient of the PTC, will get
> you closer to the ideal world. Whether its own coeff is +100 or -100.

Its just never that. The +-100ppm (or 50 or 25ppm) figure is only an 
outer limit, in reality they can be somewhere between.

Cheers,
  René