F40J2R0 Wirewound Chassis Mount Resistor – Equivalent & Substitute Parts

Part Overview

The F40J2R0 is a 2 Ohms ±5% 40W wirewound chassis mount resistor manufactured by Ohmite, part of the Stackohm® 250 series. This component is designed for high-power applications requiring stable resistance performance across extended temperature ranges. The part is currently active in production with 696 units in stock. Substitute parts may be required due to application power requirements, thermal management considerations, or inventory availability.

Substiute Parts

F40J2R0

OhmiteIn Stock: 718F40J2R0 Datasheet

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F55J2R0

OhmiteIn Stock: 880F55J2R0 Datasheet

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Key Parameters

Substitute Part Grouping Explanation

The F55J2R0 qualifies as a direct substitute for the F40J2R0 based on the following criteria:

Matching Parameters (Substitution Basis):

• Resistance value: 2 Ohms (identical)
• Tolerance: ±5% (identical)
• Composition: Wirewound (identical)
• Temperature coefficient: ±400ppm/°C (identical)
• Operating temperature range: -55°C to 350°C (identical)
• Coating/housing type: Vitreous Enamel Coated (identical)
• Mounting feature: Flange Braces, Right Angle (identical)
• Lead style: Solder Lugs (identical)
• Package/case: Radial, Flat Oval (identical)
• Series: Stackohm® 250 (identical)

Differentiating Parameter:

• Power rating: F55J2R0 provides 55W versus 40W in the F40J2R0

The F55J2R0 represents an upgrade path for applications requiring higher power dissipation capability while maintaining all other electrical and mechanical characteristics.

Parameter Comparison

Engineering Selection Recommendations

Both the F40J2R0 and F55J2R0 are active production components from Ohmite's Stackohm® 250 series with identical regulatory status (RoHS non-compliant, ECCN EAR99, HTSUS 8533.29.0000).

The F55J2R0 is suitable as a substitute when:

• Application power dissipation exceeds 40W but remains within 55W
• Thermal management or reliability margins require higher power rating capability
• Physical space constraints permit the increased length (4.600" versus 2.000")

The F40J2R0 remains the appropriate selection when:

• Power dissipation does not exceed 40W
• Physical space is constrained to the smaller form factor
• Cost optimization is a primary consideration

Both parts maintain identical electrical performance characteristics, temperature stability, and mounting compatibility.

Frequently Asked Questions (FAQ)

Q: Can the F55J2R0 directly replace the F40J2R0 in existing designs?

A: The F55J2R0 is electrically and mechanically compatible with the F40J2R0 provided that the increased physical length (4.600" versus 2.000") does not conflict with available mounting space. Both components share identical resistance, tolerance, temperature coefficient, operating range, mounting features, and lead configuration.

Q: What is the primary difference between these two parts?

A: The F55J2R0 provides a 55W power rating compared to the 40W rating of the F40J2R0. All other specifications remain identical.

Q: Are there any compliance or certification differences?

A: Both parts carry identical regulatory designations: RoHS non-compliant, ECCN EAR99, and HTSUS 8533.29.0000. No compliance advantage exists between the two options.

Q: Does the F55J2R0 have different thermal characteristics?

A: Both parts operate across the same temperature range (-55°C to 350°C) and share identical temperature coefficient (±400ppm/°C). The higher power rating of the F55J2R0 reflects increased thermal dissipation capability rather than different thermal performance.

Q: What packaging considerations apply to substitution?

A: Both parts are supplied in bulk packaging with identical lead style (solder lugs) and package configuration (radial, flat oval). The primary consideration is the increased length of the F55J2R0, which must be accommodated in the PCB layout and mechanical assembly.