Engineering Reference · Application Notes
We make the parts — these articles explain how they work, what standards they're built to, and how to choose between them. No marketing fluff. Written for design engineers and sourcing leads who want to understand the technology before they specify it.
RTD · STANDARDS
What "Class A" and "Class B" actually mean, why the 2008 revision changed who has to comply, and how wire-wound (W) and thin-film (F) tolerance suffixes work under the current standard.
PTC · MOTOR PROTECTION
Single-element (44081) versus triple-element (44082) PTC thermistors, the R-T curve breakpoints, and how the standard was renumbered to DIN VDE V 0898-1-401 without changing the specs.
NTC · THEORY
Why a single beta constant is good enough for most appliances, when you need the three-coefficient Steinhart-Hart fit, and how to convert between them without losing accuracy.
RTD · MATERIAL
PTFE, FEP and PFA compared. How a fully cured fluoropolymer body survives vacuum-impregnation varnish, AC 2.5 kV dielectric tests, and 25-year service inside a stator slot.
RTD · WIRING
How lead-resistance error scales with cable length, why 3-wire is the industrial default, and the lab cases where only a 4-wire Kelvin connection will hold accuracy.
KTY · SILICON
The diffused-resistance principle behind KTY81, KTY83 and KTY84, why the curve is near-linear, and where these parts beat both NTCs and RTDs in motor-controller feedback loops.
MOTORS · IEC 60085
The 105 / 130 / 155 / 180 °C ladder, why most modern motors are built "F-insulated, B-rise", and how that decision flows into your PTC trip-point selection.
SELECTION GUIDE
Accuracy, range, cost and response time in one comparison table. Why HVAC favours NTCs below 150 °C, why heavy industry still defaults to Pt100, and where a thermocouple is unavoidable.
UNDERFLOOR HEATING
Moisture ingress through heat-shrink tubing is the dominant failure mode for in-slab floor sensors. We look at why, what the IP68 / over-mould alternative gives up in cost, and what it pays back in service life.
PROTECTION CIRCUIT
The 4.5 kΩ trip and 2.75 kΩ reset thresholds, why three sensors are wired in series, and how DIN EN 60947-8 defines the relay-side behaviour around them.
NTC · RELIABILITY
Self-heating, thermal runaway, mechanical stress, lead-pull. A field-engineer's view of what actually goes wrong with NTCs in production, and how to design around it.
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