2.3.3 Resistors and Heating

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Resistors

Basic requirements for resistors (still one of the most numerous component in circuits) are:

Large region of R values (= device resistance in Ω) within one production technology.
Small (ideally vanishing) temperature coefficient .
Minimal noise.
Small dependence of ρ on production parameters (good repeatability).
No Ageing.
Small thermoelectrical coefficients to Cu (you want a resistor, not a thermoelement).

Materials of choice include

Ta, Ta based alloys, and in particular "Constantan" (55% Cu, 44% Ni, 1% Mn), a resistor material with an especially small temperature coefficient α_ρ, but a large thermoelectric coefficient).
Strange mixtures of conductors and insulators including "Cermet" (short for Ceramics - Metals), e.g. Cr - SiO₂.

Details and data in the (future) link.

Heating

Basic requirements for heating elements are:

High melting point.
Chemical stability at high temperatures and in potentially corrosive environments.
Mechanical strength at high temperatures.

The choice of a materials depends significantly on the range of temperatures envisioned. We have:

FeNiCr, FeNiAl alloys.
Pt, W, Ta, Mo - stable elements with a high melting point.
MoSi₂ Among more industrial applications also used as heaters in dish washers - this is very aggressive environment!
Graphite (up to 3000 K in non-oxidizing gas).

Some details and data can be found in the links.

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