Precision resistor refers to a resistor whose resistance error, thermal stability (temperature coefficient), and distributed parameters (distributed capacitance and distributed inductance) meet certain standards. The following are the main categories and characteristics of precision resistors:
1、 Classified by material
Material and Structure: Metal film is used as the resistance material, usually cylindrical in shape.
Characteristic: It has high accuracy, but the resistance temperature coefficient and distribution parameter indicators are slightly lower. This type of resistor has high precision and stable resistance, but the film layer is relatively thin and fragile, and the spiral cutting and crimping parts are prone to problems.
Application: Widely used in communication equipment, medical electronic equipment, testing and measurement equipment, automotive electronics, industrial products and other fields.
Wire wound precision resistor
Materials and Structure: Made by winding copper, manganese copper, or nickel chromium alloy wires around a ceramic frame, the surface is often coated with protective paint or glass glaze, and there are two types: fixed and adjustable. Most precision wire wound resistors are packaged in silicone resin because this packaging does not have a high-temperature sintering process and will not affect the electrical properties of the winding material.
Features: high temperature resistance, good thermal stability, low temperature coefficient, high power, high resistance accuracy. When there are many turns of wire wound precision resistors, the non inductive winding method is often used, which means that the number of turns wound in the forward direction and the number of turns wound in the reverse direction are the same, in order to minimize the distributed inductance as much as possible.
Application: Suitable for precision instruments, electronic devices, and other AC/DC circuits. Rectangular frame shaped wire wound precision resistors are commonly used in instruments and meters. Once damaged, new alloy resistance wires with the same material, diameter, and length as the original resistance alloy wire can be uniformly wound on the original frame instead.
Metal foil precision resistor
Materials and Structure: Special metal foil with known and controllable characteristics is applied onto a special ceramic substrate, and then a high-precision process is used to photolithography the resistance circuit.
Features: High precision, resistance temperature coefficient, and distribution parameter indicators. This resistor combines important characteristics such as low TCR (temperature coefficient), long-term stability, no inductive reactance, no ESD (electrostatic discharge) induction, low capacitance, fast thermal stability, and low noise. For example, its accuracy can reach 10-6, temperature coefficient can reach ± 0.3 × 10-6/℃, distributed capacitance can be less than 0.5pF, and distributed inductance can be less than 0.1 μ H.
Application: Widely used in inertial navigation, power distribution control, precision measurement and other systems in aerospace and navigation, as a comparison standard for current and voltage, constant current and constant voltage circuit components, various shunt voltage ratio networks, etc.
2、 Classified by technology
Precision thin film resistor
Technical features: Made through long-term multi-layer film deposition, high-precision resistance adjustment, and later screening.
Features: It can achieve a temperature drift of ± 2ppm/° C and an accuracy of ± 0.01%, as well as good long-term stability. But its disadvantages are that the power is not large, the low resistance part has poor indicators, is not anti-static, has a poor power coefficient, and it is difficult to meet the supply of small batches, and the consistency between different batches is not good.
Application: Suitable for situations that require high precision and stability.
Precision thick film resistor
Technical features: Made using thick film technology.
Characteristics: It occupies a mainstream position in high-voltage, high resistance, and high-precision applications. But its disadvantage is that it is difficult to achieve high-precision low-temperature drift in the low resistance part, and the noise index is not good. Its long-term stability is generally worse than other precision resistors.
Application: Suitable for occasions that require high voltage and high resistance.
3、 Classified by packaging form
SMT precision resistor
Features: Small size, light weight, suitable for large-scale production of modern electronic products.
Application: Widely used in various portable electronic devices and precision instruments.
Plug in precision resistor
Features: Large size, but good heat dissipation performance, suitable for high-power applications.
Application: Suitable for situations that require high power and high temperature tolerance.
4、 Other categories
Precision alloy resistor
Material: Mainly using alloy materials such as manganese copper, constantan, etc.
Characteristics: It has a low temperature coefficient and high stability, suitable for low resistance and high current applications.
Application: Commonly used in circuits such as current detection and voltage sampling.
Precision sampling resistor
Characteristics: Specially used for resistors in sampling circuits, requiring high accuracy and low temperature coefficient.
Application: Widely used in power management, battery management systems, and other applications that require precise sampling of current or voltage.
Precision resistor refers to a resistor whose resistance error, thermal stability (temperature coefficient), and distributed parameters (distributed capacitance and distributed inductance) meet certain standards. The following are the main categories and characteristics of precision resistors:
1、 Classified by material
Metal film precision resistor
Material and Structure: Metal film is used as the resistance material, usually cylindrical in shape.
Characteristic: It has high accuracy, but the resistance temperature coefficient and distribution parameter indicators are slightly lower. This type of resistor has high precision and stable resistance, but the film layer is relatively thin and fragile, and the spiral cutting and crimping parts are prone to problems.
Application: Widely used in communication equipment, medical electronic equipment, testing and measurement equipment, automotive electronics, industrial products and other fields.
Wire wound precision resistor
Materials and Structure: Made by winding copper, manganese copper, or nickel chromium alloy wires around a ceramic frame, the surface is often coated with protective paint or glass glaze, and there are two types: fixed and adjustable. Most precision wire wound resistors are packaged in silicone resin because this packaging does not have a high-temperature sintering process and will not affect the electrical properties of the winding material.
Features: high temperature resistance, good thermal stability, low temperature coefficient, high power, high resistance accuracy. When there are many turns of wire wound precision resistors, the non inductive winding method is often used, which means that the number of turns for forward winding and reverse winding are the same, in order to minimize the distributed inductance as much as possible.
Application: Suitable for precision instruments, electronic devices, and other AC/DC circuits. Rectangular frame shaped wire wound precision resistors are commonly used in instruments and meters. Once damaged, new alloy resistance wires with the same material, diameter, and length as the original resistance alloy wire can be uniformly wound on the original frame instead.
Metal foil precision resistor
Materials and Structure: Special metal foil with known and controllable characteristics is applied onto a special ceramic substrate, and then a high-precision process is used to photolithography the resistance circuit.
Features: High precision, resistance temperature coefficient, and distribution parameter indicators. This resistor combines important characteristics such as low TCR (temperature coefficient), long-term stability, no inductive reactance, no ESD (electrostatic discharge) induction, low capacitance, fast thermal stability, and low noise. For example, its accuracy can reach 10-6, temperature coefficient can reach ± 0.3 × 10-6/℃, distributed capacitance can be less than 0.5pF, and distributed inductance can be less than 0.1 μ H.
Application: Widely used in inertial navigation, power distribution control, precision measurement and other systems in aerospace and navigation, as a comparison standard for current and voltage, constant current and constant voltage circuit components, various shunt voltage ratio networks, etc.
2、 Classified by technology
Precision thin film resistor
Technical features: Made through long-term multi-layer film deposition, high-precision resistance adjustment, and later screening.
Features: It can achieve a temperature drift of ± 2ppm/° C and an accuracy of ± 0.01%, as well as good long-term stability. But its disadvantages are that the power is not large, the low resistance part has poor indicators, is not anti-static, has a poor power coefficient, and it is difficult to meet the supply of small batches, and the consistency between different batches is not good.
Application: Suitable for situations that require high precision and stability.
Precision thick film resistor
Technical features: Made using thick film technology.
Characteristics: It occupies a mainstream position in high-voltage, high resistance, and high-precision applications. But its disadvantage is that it is difficult to achieve high-precision low-temperature drift in the low resistance part, and the noise index is not good. Its long-term stability is generally worse than other precision resistors.
Application: Suitable for occasions that require high voltage and high resistance.
3、 Classified by packaging form
SMT precision resistor
Features: Small size, light weight, suitable for large-scale production of modern electronic products.
Application: Widely used in various portable electronic devices and precision instruments.
Plug in precision resistor
Features: Large size, but good heat dissipation performance, suitable for high-power applications.
Application: Suitable for situations that require high power and high temperature tolerance.
4、 Other categories
Precision alloy resistor
Material: Mainly using alloy materials such as manganese copper, constantan, etc.
Characteristics: It has a low temperature coefficient and high stability, suitable for low resistance and high current applications.
Application: Commonly used in circuits such as current detection and voltage sampling.
Precision sampling resistor
Characteristics: Specially used for resistors in sampling circuits, requiring high accuracy and low temperature coefficient.
Application: Widely used in power management, battery management systems, and other applications that require precise sampling of current or voltage.