Patent of lead enamelled wire winding

1. Film type: a carbon film, a metal film, a metal oxide film, etc. Deposited on a glass or ceramic substrate to form a resistive film, the thickness of which is usually less than several microns. (1) metal film resistor (model: RJ). On the surface of ceramic skeleton, a layer of metal film or alloy film is evaporated and deposited by vacuum high temperature or combustion infiltration process. It is characterized by high accuracy, good stability, low noise, small volume, good high-frequency characteristics, wide allowable working environment temperature range (-55 ~+ 125℃) and low temperature coefficient ((50 ~ 100) × 10). At present, it is one of the most widely used resistors in electronic circuits. Commonly used rated powers are 1/8W, 1/4W, 1/2W, 1W, 2W, etc. , the nominal resistance is between 10W and 10MW. () The metal oxide layer with tin dioxide as the main body is formed by chemical reaction at high temperature. Because of the thick oxide film, the resistor has excellent pulse, high frequency and overload performance, wear resistance, corrosion resistance and stable chemical properties. However, the resistance range is narrow and the temperature coefficient is worse than that of metal film. (3) Carbon film resistance (model: RT). On the surface of ceramic skeleton, hydrocarbons are decomposed and deposited into carbon crystal conductive films by vacuum high temperature evaporation. Carbon film has low resistance, wide resistance range (10W ~ 10MW) and negative temperature coefficient. The commonly used rated power is 1/8W ~ 10W, and the accuracy grade is 5% and 10. Widely used in general electronic products. 2. Resistors made of alloy drawn into alloy wire or rolled into alloy foil mainly include: (1) wire wound resistor (model: RX). Kang copper wire or Ni-Cr alloy wire is wound on the magnetic tube, and the outer layer is coated with enamel or glass glaze for protection. Wire wound resistor has the characteristics of high stability, high precision and high power. The temperature coefficient can be less than. The accuracy is higher than 0.0 1%, and the maximum power can reach 200W W, but the disadvantage of wire-wound resistor is that its inductance and distributed capacitance are relatively large, so it is not suitable for high-frequency circuits. (2) Precision gold foil resistor (model: RJ). A certain pattern is etched on the glass substrate by photolithography, and the epoxy resin protective layer is coated, and the lead is packaged to form a resistor. Therefore, it has high precision, good stability and good high frequency response. The precision of the resistor can reach 0.00 1%, the stability is 5× 10-4%/ year, and the temperature coefficient is 10-6/℃. It can be seen that it is a high-precision resistor. 3. However, the electrical characteristics are poor. It is often used in some special fields (such as aerospace industry, submarine cable and so on). There are many kinds of synthetic resistors, which can be divided into general type, high resistance type and high voltage type according to their uses. (1) metallic glass glaze resistor (model: RI). Using inorganic material as adhesive, a resistive film was formed on ceramic substrate by printing and sintering process. The resistor has high heat resistance and moisture resistance. It is usually used to make miniaturized SMD resistors. (2) Solid-core resistor (model: RS), which is made of organic resin and carbon powder and then hot pressed. The volume is equivalent to the resistance of metal film with the same power, but the noise is higher than the resistance of metal film. The resistance value is between 4.7W and 22MW. The accuracy levels are 5%, 10% and 20%. (3) Synthetic film resistance (RH). Synthetic thin film resistors can be made into high voltage type and high resistance type. The resistance range of high-resistance resistor is 65438+100MW ~106MW, and the allowable errors are 5% and 65438+. The withstand voltage is divided into two grades: 10kV and 35kV. (4) Thick film resistor network (resistor group). It is based on high alumina porcelain, and through the processes of integrated mask, lithography and sintering, a plurality of resistors with consistent parameters and properties are made on a substrate and connected into a resistor network, also called integrated resistor. Integrated resistor has the characteristics of small temperature coefficient and wide resistance range. Good parameter symmetry. At present, it has been more and more used in various electronic devices. 4. Sensitive semiconductor resistors made of different materials and processes are sensitive to non-electric physical quantities such as temperature, illumination, humidity, pressure, magnetic flux and gas concentration. This kind of resistance is called sensitive resistance. Using these different types of resistors, it can be used as a sensor to detect different physical quantities. This kind of resistor is mainly used in the field of automatic detection and automatic control. 3. Marking methods of commonly used resistors. The identification methods of common electronic components should reflect their types, materials and main electrical parameters. There are three commonly used marking methods for resistors: direct marking method, text symbol method and color coding method. 1. The direct marking method is to print the main parameters of the part directly on the surface of the part. This method is mainly used for resistors with relatively high power. If RYC-50-T- 1K5- 10% is printed on the surface of the resistor, it means that the rated power of the moisture-resistant enamelled wire-wound adjustable resistor is 50W, the resistance value is 1.5kW, and the allowable error is 10%. 2. Text Symbol Method Traditional resistor text symbol labeling is to use text symbols on the resistor body to indicate the resistance, precision, power and material of the resistor. For example, the unit of resistance is expressed by W, kW and MW, and the accuracy is expressed by grades J (5%), K (10%) and M (? The material of the resistor can be distinguished by the color of its appearance. With the continuous miniaturization of electronic components, especially the continuous progress of surface mount components (SMC and SMD) manufacturing technology, the volume of resistors is getting smaller and smaller, and the text symbols marked on the surface of components have also been reformed accordingly. Generally, only three digits are used to mark the resistance value. The accuracy level is no longer expressed (generally less than 5%). The specific provisions are as follows: (1) The surface of the element is painted black to indicate the resistance. (2) The basic marking unit of resistor is ohm (W), and its value is marked with three digits. (3) For resistors with more than ten basic mark units, the first two digits represent the significant digits of the numerical value, and the third digit represents the multiplying power of the numerical value. For example, 223 indicates that its resistance value is 22× 103 = 22kW. (4) For components with less than ten basic marking units, the first and third digits represent the significant digits of the numerical value, and the second digit represents the decimal point with the letter "r". For example, 3R9 indicates that its resistance value is 3.9W.3 Color coding method is the most widely used method for low power resistors. Generally, the background is used to distinguish the types of resistors: for example, light colors (light green, light blue, light brown) indicate carbon film resistance, red indicates metal or metal oxide film resistance, and dark green indicates wire wound resistance. Generally speaking, the color ring is used to indicate the value and accuracy of resistance. The most common resistors use four color rings to represent their resistance values and allowable deviations. The first and second rings represent significant numbers, and the third ring represents multiplication (multiplier). The fourth ring, which is far from the first three rings, is accurate. Precision resistors are marked by five color rings, the first, second and third rings represent significant numbers, the fourth ring represents magnification, and the fifth ring, which is far from the first four rings, represents accuracy. The definition of color code is shown in Table 2-3. Figure 2. 1.2 is the labeling diagram of two kinds of color ring resistances.