“Resistance: Changing with the Heat.”
Table of Contents
Effects of Temperature on Electrical Resistance
Resistance is a fundamental property of materials that describes how difficult it is for electric current to flow through them. It is measured in ohms and is influenced by various factors, including temperature. The relationship between resistance and temperature is a well-known phenomenon in the field of physics and plays a crucial role in the design and operation of electrical circuits and devices.
| POP-8300 free chlorine online analyzer | ||
| System Model | POP-8300 free chlorine online analyzer | |
| Measurement configuration | (HClO)free chlorine.. | |
| total free chlorine/(ClO2)/pH/Temperature | ||
| Free chlorine | (0.00-2.00)mg/L(ppm); (0.00-20.00)mg/L(ppm) | |
| Measurement | pH | 2.00-12.00 |
| range | Temperature | (0.0-99.9)℃ |
| Free chlorine | 0.01mg/L(ppm) | |
| Resolution | pH | 0.01 |
| Temperature | 0.1℃ | |
| Free chlorine | Indication error 10% | |
| Accuracy | pH | 0.1pH |
| Temperature | ±0.5℃ | |
| Sensor life | pH/free chlorine sensor | 12months(The service life is closely related to the measurement medium and maintenance frequency) |
| Communication interface | RS485 | MODBUS RTU communication protocol |
| Number of channels | Double channels | |
| (4-20)mA | Technical feature | Isolated, reversible, completely adjustable, instrument/transmitter dual mode |
| output | Channel configuration | Programmable point to Free chlorine, chlorine dioxide, Temperature, pH |
| Loop resistance | 400Ω(Max), DC 24V | |
| Transmission accuracy | ±0.1mA | |
| Number of channels | Double channels | |
| Contact mode | The first and second for photoelectric switch | |
| Control output | Load capacity | Load current 50mA(Max)，AC/DC 30V |
| Control point | Programmable function(Free chlorine, chlorine dioxide, Temperature, pH, Timing) | |
| Load capacity | Load current 50mA(Max)，AC/DC 30V | |
| Control point | Programmable function(Free chlorine, chlorine dioxide, Temperature, pH, Timing) | |
| Power supply | Connected to electric supply | |
| AC80-260V;50/60Hz,compatible with all international | ||
| market power standards(110V;220V;260V;50/60Hz). | ||
| Working environment | Temperature:(5-50)℃；relative humidity:≤85% RH(non condensation) | |
| Power Consumption | ＜20W | |
| Storage environment | Temperature:(-20-70)℃；relative humidity:≤85%RH(non condensation) | |
| Installation | Wall mounted(with the preset back cover) | |
| Cabinet weight | ≤10kg | |
| Cabinet dimension | 570*mm*380mm*130mm(H×W×D) | |
When a material is subjected to an electric current, the movement of electrons within the material generates heat. This heat causes the atoms in the material to vibrate more vigorously, which in turn increases the collisions between electrons and atoms. These collisions impede the flow of electrons, resulting in an increase in resistance. This phenomenon is known as the temperature coefficient of resistance.
| Instrument model | FET-8920 | |
| Measurement range | Instantaneous flow | (0~2000)m3/h |
| Accumulative flow | (0~99999999)m3 | |
| Flow rate | (0.5~5)m/s | |
| Resolution | 0.001m3/h | |
| Accuracy level | Less than 2.5% RS or 0.025m/s.whichever is the largest | |
| Conductivity | >20μS/cm | |
| (4~20)mA output | Number of channels | Single channel |
| Technical features | Isolated,reversible,adjustable, meter/transmission dual mode | |
| Loop resistance | 400Ω（Max）, DC 24V | |
| Transmission accuracy | ±0.1mA | |
| Control output | Number of channels | Single channel |
| Electrical contact | Semiconductor photoelectric relay | |
| Load capacity | 50mA（Max）, DC 30V | |
| Control mode | Instantaneous amount upper/lower limit alarm | |
| Digital output | RS485(MODBUS protocol ),Impulse output1KHz | |
| Working power | Power supply | DC 9~28V |
| source | Power Consumption | ≤3.0W |
| Diameter | DN40~DN300(can be customized) | |
| Working environment | Temperature:(0~50) ℃; Relative humidity: ≤85%RH(none condensation) | |
| Storage environment | Temperature:(-20~60) ℃; Relative humidity: ≤85%RH(none condensation) | |
| Protection grade | IP65 | |
| Installation method | Insertion pipeline installation | |
Different materials exhibit different temperature coefficients of resistance. Some materials, such as metals like copper and aluminum, have positive temperature coefficients, meaning that their resistance increases with temperature. Other materials, such as semiconductors like silicon and germanium, have negative temperature coefficients, meaning that their resistance decreases with temperature.
The temperature coefficient of resistance is typically expressed as a percentage change in resistance per degree Celsius. For example, a material with a temperature coefficient of 0.0039 ohms per ohm per degree Celsius will experience a 0.39% increase in resistance for every degree Celsius increase in temperature.
The reason why resistance changes with temperature lies in the atomic structure of materials. In metals, electrons move freely through the lattice of positively charged ions. As the temperature increases, the ions vibrate more vigorously, creating more obstacles for the electrons to navigate. This increased vibration leads to more frequent collisions between electrons and ions, resulting in higher resistance.
In semiconductors, the behavior is slightly different. At low temperatures, semiconductors behave like insulators, with very high resistance. As the temperature increases, the energy levels of the electrons in the semiconductor also increase, allowing them to move more freely through the material. This increased mobility of electrons leads to a decrease in resistance.
The temperature dependence of resistance has important implications for the design and performance of electronic devices. For example, in circuits where precise control of resistance is required, temperature compensation techniques may be employed to counteract the effects of temperature on resistance. In other cases, the temperature dependence of resistance may be exploited to create devices with specific temperature-sensitive properties, such as thermistors and temperature sensors.
In conclusion, the relationship between resistance and temperature is a fundamental aspect of the behavior of materials in electrical circuits. Understanding how resistance changes with temperature is essential for designing and operating electronic devices effectively. By considering the temperature coefficient of resistance and its impact on different materials, engineers and scientists can develop innovative solutions to address the challenges posed by temperature variations in electrical systems.
Factors Influencing Resistance Variation with Temperature
Resistance is a fundamental property of any material that impedes the flow of electric current. It is a crucial factor in determining the behavior of electrical circuits and devices. One of the key factors that influence resistance is temperature. The relationship between resistance and temperature is a well-established phenomenon in physics, and understanding this relationship is essential for designing and analyzing electrical systems.
In general, the resistance of a material increases with an increase in temperature. This is known as positive temperature coefficient resistance. The reason behind this behavior lies in the atomic structure of the material. At a microscopic level, the atoms in a material vibrate due to thermal energy. As the temperature rises, the amplitude of these vibrations increases, causing the atoms to collide more frequently with the electrons that carry the electric current. This increased collision rate leads to a higher resistance to the flow of current.
The relationship between resistance and temperature can be described by the temperature coefficient of resistance (TCR). The TCR is a measure of how much the resistance of a material changes per degree Celsius change in temperature. Different materials have different TCR values, which determine how their resistance varies with temperature. For example, metals typically have positive TCR values, while semiconductors may have negative TCR values.
One of the most common applications of the temperature dependence of resistance is in the design of temperature sensors. Thermistors, for example, are devices whose resistance changes significantly with temperature. This property makes them ideal for measuring temperature in various applications, such as in thermostats, automotive systems, and medical devices.
It is important to note that not all materials exhibit a positive temperature coefficient of resistance. Some materials, such as superconductors, have a negative temperature coefficient of resistance. In these materials, the resistance decreases as the temperature decreases, eventually reaching zero at a critical temperature known as the superconducting transition temperature. This unique behavior allows superconductors to conduct electricity with zero resistance, making them highly valuable for applications such as magnetic resonance imaging (MRI) machines and particle accelerators.
The temperature dependence of resistance also plays a crucial role in the performance of electronic devices. For example, in integrated circuits, the resistance of the conductive traces and components can change with temperature, affecting the overall performance of the circuit. Engineers must take into account the temperature coefficient of resistance when designing circuits to ensure their reliability and stability over a wide range of operating temperatures.
In conclusion, the relationship between resistance and temperature is a fundamental aspect of electrical engineering and physics. Understanding how resistance changes with temperature is essential for designing and analyzing electrical systems, as well as for developing temperature sensors and electronic devices. The temperature coefficient of resistance provides a quantitative measure of this relationship, allowing engineers to predict and control the behavior of materials under different temperature conditions. By considering the temperature dependence of resistance, engineers can optimize the performance and reliability of electrical systems in a wide range of applications.
