Oven voltage controller

Oven voltage controller


评论

发表评论

此博客中的热门博文

Tolerances on Temperature Reading

图片
1. JIS C1602 – 1995 IEC 584-2-1982 (Amendment 1 – 1989) BS/EN 60584-2-1993 DIN/IEC 584-2-1992 Note: 1. Tolerance denotes the maximum allowable value obtained by subtracting the temperature reading or the temperature at the hot junction from the standard temperature converted from the applicable temperature EMF table. 2. Tolerance Class 1 for Type R and S only apply to the Standard or Refence thermocouple. 3. │t│denotes the value of temperature (°C) irrespective of positive (+) or negative (-) sign. 4. Tolerances listed in this page apply to the new thermocouple wires. • not standardized yet by JIS 2. Tolerance on Temperature Reading To ASTM E 230-1998, E988 – 1996 Note: The above color codes are in accordance with ASTM E 230 – 1998 Contact: thermocouplesupplier@gmail.com
阅读全文

Thermocouple Construction Materials

图片
The most basic thermocouple construction is the wire type consisting of two dissimilar metals homogeneously joined at one end to form the measuring junction. All wire-type thermocouples have an exposed junction. While wire-type thermocouples offer good response time, ruggedness, and high temperature use, they are susceptible to environmental conditions and therefore must be protected. Mineral insulated thermocouples overcome the disadvantages of wire type construction by imbedding the thermocouple wires in ceramic insulation and protecting them with a metallic sheath. The mineral insulated cable (MI cable) design is based on small mass and high thermal conductivity which in turn promotes rapid heat transfer from the heat source to the measuring junction.The sheaths are impervious to most liquids and gases and withstand high external pressures. The seamless design protects against moisture or other contaminants attacking the thermocouple elements. Since the only materials used to make...
阅读全文

Temperature Sensor Theory

图片
There are many different types of temperature sensors. We will deal with the two most common types, thermocouples and RTDs.Not because they are the most common, but because these two are the only two types Smart Sensors makes. How do Thermocouples  work? In 1821 Thomas Seebeck, while making a pot of tea, discovered that when two dissimilar metals are joined together, a current flows, as long as the temperature at one of the junctions is at a higher temperature than the other junction. Little did he know, as he finished his tea, that he would be famous for discovering the current that flowed in this circuit and the EMF (Electro Motive Force) that produced this current would be forever called the Seebeck Effect. Seebeck circuit showing the positive (kp) and negative (kn) of a Chromel Alumel thermocouple. If the temperatures (T1 and T2) are different at the two junctions a current will flow in the circuit. Seebeck was responsible for developing the most rugged and simp...
阅读全文