Carbon film resistance:

Carbon film resistors used to be the most used resistors in electronics, electrical appliances, and information products, the cheapest price, and high reliability in quality and stability. Because it is a lead-type resistor, it is convenient to install and repair by hand, and it is also the cheapest among the lead-type resistors. It is now used in some low-value low-end products such as power supplies and adapters or products of early design.

Carbon film resistors are resistors commonly used in the early days. Vacuum coating technology was used to spray a layer of carbon film on the porcelain rod, and then the outer layer of the carbon film was cut into a spiral pattern. The resistance value was determined according to the number of spiral patterns. The larger the number of lines, the greater the resistance value. Finally, the outer layer is coated with epoxy resin to protect it. Carbon film resistors are still widely used in various products and are the most basic components of electronics, electrical appliances, equipment and information products.

Metal film resistor

Metal film resistors have been widely used so far, with high accuracy, stable performance, and simple and lightweight structure. A metal film resistor is a resistor that uses a special metal or alloy as the resistance material and uses vacuum evaporation or sputtering to basically form a resistance film layer on ceramic or glass. This type of resistor is generally made by a vacuum evaporation process, that is, the alloy is heated in a vacuum, and the alloy is evaporated, so that a conductive metal film is formed on the surface of the porcelain rod. The resistance value can be controlled by engraving the groove and changing the thickness of the metal film. Its heat resistance, noise potential, temperature coefficient, voltage coefficient and other electrical properties are better than carbon film resistors.

The manufacturing process of the metal film resistor is relatively flexible. Not only its material composition and film thickness can be adjusted, but also the resistance value can be adjusted through the groove, so it can be made into a resistor with good performance and a wide range of resistance values. Compared with carbon film resistors, it has a small size, low noise, and good stability, but it costs more. It is widely used as a precision and high stability resistor, and it is also widely used in various radio and electronic equipment.

Oxide film resistance

The metal oxide film is formed by decomposition and deposition of a metal salt solution sprayed on a hot ceramic framework. Its appearance is similar to that of a metal film. It has better oxidation resistance than a metal film and has excellent pulse overload characteristics. Performance, but its resistance value range is small and the temperature coefficient is large.

Metal oxide film resistors have a resistance range of 1Ω ~ 200kΩ. This resistor is formed by the decomposition of hydrolyzed metal salt solutions (such as tin tetrachloride and antimony trichloride) on the surface of hot glass or ceramics. . With different manufacturing conditions, the performance of resistors also varies greatly.

The main characteristics of metal oxide film resistors are high temperature resistance. The operating temperature range is + 140 ~ 235 ℃. They can be overloaded in a short time; the temperature coefficient of resistance is ± 3 × 10-4 / ℃; the chemical stability is good. Low-power resistors do not exceed 100 kohms, so their range of application is limited, but they can be used to complement the low-resistance part of metal film resistors.

Winding resistance

The winding resistance is made of constantan or nickel-chromium alloy resistance wire wound on a ceramic skeleton. It is characterized by stable work, good heat resistance, small error range, suitable for high-power occasions, and the rated power is generally 1 watt Above. Wirewound resistors have the advantages of high reliability, good stability, no non-linearity, and small current noise, temperature and voltage coefficient. It is worth noting that wirewound resistors have inductive and capacitive effects and are generally not suitable for Frequency above 50kHz. Due to the skin effect, the resistance of wire-wound resistors usually increases with increasing frequency. Precision fixed wire-wound resistors have precise resistance values and have very high stability. Power-type wire-wound resistors can withstand specific stability. The working voltage is much higher than the pulse voltage, but it should be derated accordingly in use. In order to ensure the long-term reliability of the circuit, the design should allow a certain resistance tolerance of the wire-wound resistor: ± 0.4% for precision wire-wound resistors; ± 1.5% for power wire-wound resistors.

The above is the difference between carbon film resistors, metal film resistors, oxide film resistors and wire wound resistors. For more information about resistors, you can choose to leave a message for us, or enter the product center, or leave a message for us.