A wire wound resistor is a special type of resistor whose core is made by winding one or more resistance wires (usually high resistivity materials such as nickel chromium alloy or copper nickel alloy) around an insulated core. This type of resistor is known for its ability to withstand high power and is suitable for circuits that require processing large currents or high energy.

Structural features:

1. Resistance wire: This is the core part of a wire wound resistor, made of high resistivity alloys such as Constantan, Evanohm, nickel chromium, etc. The material and diameter of the resistance wire determine the resistance value and the power it can withstand.

2. Core: Usually made of ceramics, fiberglass, or similar insulating materials, used to support and fix resistance wires.

3. Shell: protects the internal structure from external environmental influences and also helps with heat dissipation. The shell can be painted, enamel, plastic or metal material.

End structure: The two ends of the resistance wire are usually welded or mechanically fixed to metal terminals for easy connection into the circuit.

working principle:

When the current passes through the winding resistor, the resistance wire will hinder the current due to the resistance characteristics of its material, thereby generating heat. This energy is converted into thermal energy, causing the temperature of the resistor to rise.

Usage scenario:

Winding resistors are mainly used in the following aspects:

1. Power circuit: Used for current limiting and voltage stabilization in high-power power supply.

2. Motor control: In the motor drive circuit, it is used to adjust the current and protect the circuit.

3. Precision instruments: In some precision measuring instruments, they are used to provide accurate resistance values.

4. Overload protection: Used as a substitute for fuses in circuits, when the current exceeds the rated value, the resistance will disconnect due to overheating, providing protection.

Selection and application precautions:

1. Power: Select the appropriate power level winding resistor based on the maximum power demand in the circuit.

2. Resistance value: Select the appropriate resistance value according to the circuit design requirements.

3. Temperature coefficient: Consider the stability of resistance at different temperatures and choose an appropriate temperature coefficient.

4. Thermal management: Due to the high heat generated by wire wound resistors during operation, it is necessary to consider their heat dissipation issues to ensure that they are not damaged or performance degraded due to overheating.

5. Packaging size: Choose the appropriate packaging size based on the circuit board space and installation method. The packaging of plug-in resistors usually adopts the following forms:

1. Axial Led Resistor:

DO-35: This is a common axial package with a diameter of approximately 3.5mm and a length of approximately 12.7mm, suitable for medium power applications.

DO-41: slightly larger than DO-35, with a diameter of approximately 4.1mm and a length of approximately 14.6mm, suitable for higher power applications.

DO-201: With a diameter of approximately 2.0mm and a length of approximately 11.5mm, it is suitable for low-power applications.

2. Radial Led Resistor:

RAD-0201: With a diameter of approximately 1.0mm and a length of approximately 2.5mm, it is suitable for very small space requirements.

RAD-0301: With a diameter of approximately 1.5mm and a length of approximately 3.0mm, it is suitable for medium size space requirements.

RAD-0402: With a diameter of approximately 2.0mm and a length of approximately 4.0mm, it is suitable for larger space requirements.

3. Special packaging:

Metal film packaging: Using metal film as a resistance material, it has a lower temperature coefficient and higher frequency characteristics.

Thick film packaging: Using thick film printing technology, the cost is relatively low, but the accuracy and stability are relatively low.

Ceramic packaging: Using ceramic materials as substrates, suitable for harsh environments such as high temperature and high humidity.

Glass packaging: Using glass materials as substrates, it has extremely high stability and reliability. Wire wound resistors are still indispensable components in certain industrial and professional applications due to their excellent power processing ability and high stability. However, due to their large size and high cost, their application in consumer electronics is not as widespread as surface mount resistors.