RWR89N18R0BSB12 Vishay Dale 18Ω 3W Wirewound Resistor

ElecSuppliers Part Number GuideAug 22, 2026

RWR89N18R0BSB12 is a Vishay Dale RWR89 series wirewound resistor designed for applications requiring stable resistance, relatively high power handling and reliable operation under demanding environmental conditions.

The component has a nominal resistance of 18 Ω, a ±1% tolerance and a rated power of 3 W. Its axial through-hole construction makes it suitable for power, control and high-reliability electronic assemblies where a larger resistor body is preferred over a compact surface-mount component.

RWR89N18R0BSB12 Key Specifications

RWR89N18R0BSB12 provides an 18 Ω resistance value with a ±1% tolerance.

The resistor has a 3 W rated power and uses wirewound construction. It is designed for through-hole PCB assembly and has an axial body style.

The component is associated with the Vishay Dale RWR89 series and is intended for applications where environmental reliability and stable performance are important.

The operating temperature capability is suitable for demanding electronic equipment, but actual power dissipation should always be evaluated according to ambient temperature and mounting conditions.

18Ω 3W Wirewound Resistor

An 18 Ω resistance value is commonly useful in power and control circuits where the resistor must handle more energy than a small signal resistor.

The 3 W rating provides additional power-handling capability for applications involving current limiting, voltage dropping, damping or load functions.

For an 18 Ω resistor, power dissipation can be calculated using:

P = I²R

At 100 mA, the resistor dissipates approximately 0.18 W.

At 200 mA, the dissipation increases to approximately 0.72 W.

At around 408 mA, the calculated dissipation approaches 3 W.

These values illustrate why current and thermal conditions should be considered when using RWR89N18R0BSB12 continuously near its rated power.

Vishay Dale RWR89 Series

RWR89N18R0BSB12 belongs to the Vishay Dale RWR89 series of wirewound resistors.

The series is designed for applications requiring rugged construction and predictable electrical performance.

Wirewound technology allows manufacturers to produce resistance values across a broad range while supporting relatively high power levels.

The RWR89 family also includes different resistance values and ordering configurations, so the complete part number is important when sourcing a specific component.

Wirewound Resistor Construction

A wirewound resistor uses resistive wire wound around an insulating core.

This construction provides good power-handling characteristics because the resistor can use a relatively large physical body to dissipate heat.

Wirewound resistors are commonly used in power circuits, industrial equipment, instrumentation and other applications where a conventional small chip resistor may not provide enough power capability.

One consideration is parasitic inductance. Because resistive wire is physically wound around a core, the component can exhibit more inductive behavior than some film-based resistor technologies.

For high-frequency circuits, this characteristic should be evaluated as part of the circuit design.

RWR89N18R0BSB12 Power Rating

The 3 W rating is one of the important characteristics of RWR89N18R0BSB12.

A resistor's rated power represents the amount of power it can dissipate under specified conditions. It does not mean that the resistor should automatically operate continuously at 3 W in every environment.

As ambient temperature rises, the available power dissipation may need to be reduced.

PCB copper area, component spacing, airflow and nearby heat sources can also affect the actual resistor temperature.

For long-term reliability, engineers normally provide additional power margin rather than designing around the absolute rating.

±1% Resistance Tolerance

RWR89N18R0BSB12 has a ±1% resistance tolerance.

For an 18 Ω nominal value, this corresponds to an expected initial resistance range of approximately 17.82 Ω to 18.18 Ω under the applicable conditions.

A 1% tolerance can be useful in circuits where resistance directly affects current, voltage or timing.

For applications requiring tighter long-term accuracy, designers should also consider temperature coefficient, aging and self-heating rather than looking only at the initial tolerance.

Axial Through-Hole Package

RWR89N18R0BSB12 uses an axial leaded construction.

Through-hole mounting provides a strong mechanical connection and can be useful in industrial equipment and assemblies exposed to vibration or mechanical stress.

The larger physical body also provides greater surface area for heat dissipation than many miniature surface-mount resistors.

When installing a 3 W axial resistor, adequate PCB clearance should be provided around the body so that heat does not excessively affect nearby components.

RWR89N18R0BSB12 Applications

RWR89N18R0BSB12 can be used in power supplies, industrial controls, instrumentation, motor-control circuits and other electronic equipment.

Potential functions include current limiting, voltage dropping, load resistance, damping and discharge circuits.

The 18 Ω value can also be used in startup or protection networks where the resistor must temporarily or continuously dissipate a meaningful amount of power.

The appropriate application depends on the expected current, duty cycle, temperature and transient conditions.

RWR89N18R0BSB12 Temperature Considerations

Temperature is an important factor when using a 3 W wirewound resistor.

The resistor generates heat whenever it dissipates electrical power. If the surrounding environment is already hot, the component has less thermal margin available.

For this reason, designers should evaluate the resistor's operating temperature under worst-case conditions.

When several power resistors are installed close together, thermal interaction should also be considered because heat from one component can increase the temperature of neighboring components.

RWR89N18R0BSB12 Replacement

When selecting a replacement, the first parameters to match are the 18 Ω resistance and ±1% tolerance.

The 3 W power rating should also be maintained or exceeded unless the circuit has been redesigned.

Engineers should then compare the package dimensions, lead spacing, temperature characteristics and resistor technology.

A small surface-mount resistor with the same 18 Ω value may not be an appropriate replacement because its thermal capability could be much lower.

For high-reliability applications, the environmental and qualification requirements of the original component should also be considered.

RWR89N18R0BSB12 for Power Applications

RWR89N18R0BSB12 combines an 18 Ω resistance, ±1% tolerance and 3 W power rating in a rugged wirewound axial package.

Its combination of resistance accuracy and power capability makes it suitable for power and control applications where a conventional low-power resistor would not provide sufficient thermal margin.

For new designs, engineers should calculate continuous and transient power dissipation, evaluate thermal conditions and consider the inductive characteristics of wirewound construction. For replacement projects, matching the complete electrical and mechanical specifications is important for reliable operation.