Introduction of winding resistance

It is made of constant alloy, manganese copper and other special alloys and wound around an insulating tube. There is a protective layer on the outside. The protective layer has two types: general enamel and moisture-proof enamel. There are two types of wire-wound resistors: fixed and adjustable, as shown in Figure 4-8. The advantages of this resistor are: accurate resistance, good electrical performance, reliable and stable work, small temperature coefficient, good heat resistance, and large power. The disadvantage is that the resistance is not large and the cost is high. Wire-wound resistors are suitable for circuits with large power requirements, and some can be used where precision resistors are required. However, due to the presence of inductance, it is not suitable for high-frequency circuits.

Advantages of winding resistance

Extremely high resistance value, low noise, stable and reliable during work, small temperature coefficient, can withstand high temperature, and can still work normally at ambient temperature of 170 ℃.

Disadvantages of winding resistance

Large volume and low resistance, mostly below 100KΩ.

Classification of winding resistance

Wire-wound resistors are divided into fixed resistors and adjustable resistors. The windings of the adjustable parts of the adjustable resistors are bare, which is not conducive to the stability of the resistance value, which is called some wire-wound resistor structures.

Winding resistance specifications

The specifications of the winding resistance mainly include accuracy error, power and temperature. The accuracy errors of the winding resistance are: ± 5%, ± 2%, ± 1%; the power range of the winding resistance is 1 / 4W ~ 10W; The rated temperature range of the resistor is 70 ° C, and the operating temperature range is -55 ° C to 155 ° C. There is also a basic winding resistance specification parameter which is the resistance value, and the nominal resistance value of the winding resistance is 10Ω.

The role of winding resistance

Wire-wound resistors are formed by winding resistance wires around an insulating skeleton, and generally use a medium with a certain resistivity, such as nickel-chromium, manganese-copper and other alloys. Wire-wound resistors are mainly used to play the role of step-down, shunt, load, feedback, energy transfer, and matching in low-frequency AC circuits, or as absorbers and voltage dividers in power circuits, and can also be used as oscillator Shunts in loop and transformer attenuation adjustment and pulse forming circuits. In addition, it can also be used for the discharge and spark suppression of filter capacitors in rectifiers. At the same time it can be widely used in home appliances, medical equipment, automotive industry, railway, aviation, military equipment and other fields.

High-power wire-wound resistor structure and manufacturing process

The process of wire-wound resistors is simple. Domestic technology is quite mature and widely used. I believe many people have a certain understanding of it, but do you know the manufacturing process of wire-wound resistors in terms of materials? What materials are needed to make a wire-wound resistor?

The first is an insulating substrate. Alumina ceramic tubes are generally used as wire insulators for wire-wound resistors. High-power wire-wound resistors usually use hollow insulating rods as the resistance matrix, while low-power wire-wound resistors usually use solid ceramic rods. It will have a great impact on the heat dissipation and electrical performance of the resistor. The high-power wire-wound resistors produced by Times Jiaying adopt high-frequency ceramic tubes as the resistance matrix, which has good heat dissipation and insulation properties.

The second is the resistance wire. The difference in the material of the resistance wire directly determines the temperature coefficient and resistance value of the resistance, and also affects the transient overload capacity of the resistance and the long-term stability of the resistance value. Nickel-chromium alloys are widely used in China, but the quality and technology of different resistance wire suppliers are very different. It is important that the composition of trace elements in the alloy is also different. High-quality resistance wire has stable performance during high temperature sintering. Times Jiaying RX20 high-power wire-wound resistor uses constantan four as the resistance wire, which has good conductivity and stability.

Finally, there are packaging materials. The packaging materials are more diversified, including insulation paint, silicone resin enamel coating, plastic packaging, ceramics, and aluminum shells. In general, insulating varnish is the cheapest packaging material, and the process is simple. You only need to coat the insulating varnish on the substrate around the resistance wire, and then dry it at low temperature. However, the insulation performance is average, and it does not help the heat dissipation of the resistor much. To this end, Times Jiaying RX20 high-power wire-wound resistors are nano-silicone coatings from Taiwan, which are non-toxic and odorless, have good insulation properties, and are heat and high temperature resistant , Can be used in high temperature and high reliability requirements.