White Papers & Guides

White Papers

Beta and Steinhart-Hart Equations Explained

QTI Engineering compares the two equations typically used to interpolate the resistance vs. temperature characteristic of NTC thermistors: the Beta Equation and the Steinhart-Hart Equation.

NTC Thermistors

Have questions about negative temperature coefficient thermistors? In this white paper, QTI engineer Gregg Lavenuta gives an overview of the general properties and features of NTC thermistors.

T020/T040 Series Stability

This white paper presents two stability tests on T020 and T040 Series thermistors at differing applied bias currents.

T150 Series Stability and Drift

This white paper explains how to calculate thermistor drift over time when exposed to temperatures above 100°C, and features the results of testing the QTI T150 line for drift in high-temperature environments.

Thermal Shock Testing

Thermal shock is one of the primary sources of temperature sensor failure in HVAC/R environments. QTI Engineering explains their semi-automated thermal shock testing system and shares the results of tests on QTIP68 and QTSSP temperature sensors from QTI and competitors.

Thermistor Performance and Reliability in Freeze/Thaw Applications

QTI Engineering put QTIP68 probes to the test in a refrigeration environment (consisting of repeated cool and defrost cycles) and recorded the performance characteristics over time. They also tested a competitor’s IP68-rated sensor and documented probe response times.

Application Notes

Handling and Soldering Methods for SMD Thermistors

QTI Engineering gives tips for safe handling and soldering of surface mount thermistors.

Steinhart-Hart Coefficients for QTI Curves and Resistance Values

A list of coefficients for QTI’s R/T curves, for use with the Steinhart-Hart equation.

Temperature Measurement and Compensation

This paper gives electrical diagrams to illustrate how to use thermistors in temperature measurement and temperature compensation.

Wire Bonding to NTC Thermistors

This application note describes the bonding specifications that QTI’s NTC gold-terminated thermistors are rated to.

How-To Guides

Computer Interfacing to an NTC Thermistor

This guide walks you through creating an analog-digital converter, and includes code to create a resistance/temperature lookup table in BASIC script.

Waffle Pack Handling Instructions

Chip thermistors can sometimes be damaged or lost when the waffle pack containing them is opened or closed.  This guide gives tips on how to safely handle the waffle pack and thermistors.

Reference Charts

Wire Gauge Information

Use this new reference sheet for information on wire gauge dimension and resistance per foot as well as decimal to fraction equivalents and standard ring lug dimensions.