Passive Components Products:

WIREWOUND RESISTORS

A wirewound resistor is a passive electrical component designed to limit or control the flow of current in a circuit. It consists of a high-resistivity metal wire, such as nickel-chromium (Nichrome) or Manganin (a copper-nickel-manganese alloy), wound around a non-conductive core made of materials like ceramic, plastic, or glass. This type of resistor is known for its precision and is commonly used in applications requiring low resistance values and high power ratings.

Wirewound resistors are ideal for high-power and industrial uses, including circuit breakers and fuses, due to their ability to handle significant power loads. These resistors are among the oldest resistor types still in production today, valued for their accuracy and durability in demanding environments.

Wirewound Resistors Overview

Wirewound resistors are versatile passive electrical components that limit current in a circuit. They come in various forms, ranging from small surface-mount components to large, tubular power resistors, some of which are heat-sinkable. Wirewound resistors are typically used in high-current applications, such as current sensing, snubber circuits, dynamic braking, voltage balancing, and as “bleed resistors.” They are available with varying temperature coefficients of resistance (TCR) and come in multiple tolerances and power ratings to suit different applications.

At Richardson RFPD, engineers receive design support to select the optimal wirewound resistor based on attributes like package type (Axial, Heat Sinkable, Radial, SMD, or Tubular), voltage rating, power rating, resistance, tolerance, operating temperature range, TCR, and dimensions.

Types of Wirewound Resistors

1. Power Wirewound Resistors
These non-inductive resistors are designed for high-power applications, capable of operating at elevated temperatures. They are commonly used in applications that require dissipating large amounts of power, with their performance influenced by operating temperatures, often derated at ambient temperatures of up to 350°C.

2. Precision Wirewound Resistors
These resistors are used in low-temperature environments where accuracy is critical, such as instrumentation applications. Precision wirewound resistors are constructed with high-quality materials like Evanohm and Stabilohm alloys, offering high resistance stability and accuracy. They are aged to ensure long-term stability and have very low temperature coefficients.

Wirewound Resistor Subcategories

• Safety Wirewound Resistors: Designed for overload conditions, these resistors have flame-retardant coatings and are available in through-hole and SMD versions.
• Precision Wirewound Resistors: Ideal for high-accuracy applications, featuring narrow tolerances and high stability, available in both through-hole and SMD versions.
• Pulse Wirewound Resistors: Capable of withstanding short-duration impulse events, these resistors are customizable for specific pulse requirements.
• Fusible Wirewound Resistors: These resistors fuse safely without generating excessive heat during sudden current surges. They are available in through-hole and SMD forms.
• General Purpose Wirewound Resistors: Suitable for a wide range of applications, offering a balance of performance, cost, and reliability in through-hole and SMD versions.
• Power Wirewound Resistors: Ceramic and aluminum-cased resistors designed to handle and dissipate significant power.

Applications of Wirewound Resistors

Wirewound resistors are widely used in various industries, including:

• Telecommunications base stations
• Audio equipment
• Medical devices
• Industrial equipment
• Smart meters
• Renewable energy systems
• Power supplies and chargers
• Lighting systems
• Instruments and gauges
• Household appliances (white goods)

Wirewound resistors are also available through IBS Electronics, an authorized distributor for many leading wirewound resistor manufacturers. They offer high-quality components suitable for diverse applications.

In addition to our franchise lines we actively stock and order parts from the following manufacturers: