Aquadag Resistance Thermometer

Resistance Thermometer Theory and Practice

1. BASIC THEORY The electrical conductivity of a metal depends on the movement of electrons through its crystal lattice. Due to thermal excitation, the electrical resistance of a conductor varies according to its temperature and this forms the basic principals of resistance thermometry. The effect is most commonly exhibited as an increase in resistance with increasing temperature, a positive te...

An A - C Resistance Thermometer Bridge

r '-' A 400 Hz bridge des igned spec ifically fo r measurin g the res istances of platinum the rmometers is desc ribed. Wh en used in conjunction with a co nvent ional 25 ohm thermometer, the instrument ca n resolve a resistance change of 2 micro-ohm s or less, or about 20 microdegrees. It is believed to be in error by no more tha n 3 micro-ohms throughout the useful temperature ra nge of a con...

An Imaging Radiation Thermometer

For many years radiation thermometers have been used to make non-contact temperature measurements of hot objects, particularly in industrial situations such as reformer furnaces, steel reheat furnaces, and ceramics kilns. They occupy an important niche in temperature measurement since any other type of thermometer would have very slim chances of surviving in these and other such hostile environ...

An improved tele-thermometer.

A thermistor leaf thermometer.

An instrument is described which allows measurements of leaf temperature within about 0.3 C. It consists of a special thermistor probe, a small circuit box, and a standard ammeter. The circuit box can easily be fixed to the meter and contains a battery, which passes 0.3 milliampere through the thermistor, and also contains an integrated circuit amplifier, so that the meter reads 20 C full scale...