43F300E Equivalent & Substitute Parts

Part Overview

The 43F300E is a 300 Ohms ±1% 3W through hole resistor manufactured by Ohmite in the Ohmicone® 40 series. This axial wirewound resistor is designed for applications requiring precision resistance with high power dissipation capability. The part is currently active in production with full RoHS compliance and unlimited moisture sensitivity rating. Equivalent and substitute parts are identified when identical electrical specifications and mechanical compatibility are maintained across alternative manufacturers.

Substiute Parts

43F300E

OhmiteIn Stock: 85943F300E Datasheet

Current PartRFQ

UB3C-300RF1

RiedonIn Stock: 1462UB3C-300RF1 Datasheet

SimilarRFQ

WW3FT300R

Stackpole Electronics IncIn Stock: 2575WW3FT300R Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the 43F300E are qualified based on matching the following critical parameters: 300 Ohms resistance value, ±1% tolerance, 3W power rating, wirewound composition, axial package configuration, ±20ppm/°C temperature coefficient, and 2-pin termination count. All identified substitutes maintain these core electrical and mechanical specifications. Operating temperature range variations and physical dimensions are secondary considerations that do not preclude substitution when primary parameters align. RoHS compliance status is documented for each part to support regulatory requirements.

Parameter Comparison

Engineering Selection Recommendations

All three parts—43F300E, UB3C-300RF1, and WW3FT300R—meet the core electrical requirements for 300 Ohms ±1% 3W axial wirewound resistor applications. Selection between these parts is determined by application-specific constraints:

The 43F300E operates to 275°C maximum and is suitable for standard industrial applications. The UB3C-300RF1 operates to 250°C and includes additional features such as current sense capability, flame proof construction, and pulse withstanding characteristics, making it appropriate for safety-critical or high-stress pulse environments. The WW3FT300R extends the operating temperature to 350°C, providing the widest thermal operating window for high-temperature applications.

Physical dimensions vary across the three parts. The UB3C-300RF1 is the most compact at 4.00mm diameter and 8.90mm length. The WW3FT300R measures 4.75mm diameter and 14.22mm length. The 43F300E is the largest at 5.60mm diameter and 15.10mm length. PCB layout constraints and thermal management requirements should guide selection based on available board space and heat dissipation needs.

All parts carry active product status and appropriate RoHS compliance certifications. The choice between ROHS3 and RoHS Compliant designations reflects different certification timelines but does not affect functional equivalence.

Frequently Asked Questions (FAQ)

Q: Can UB3C-300RF1 replace 43F300E in all applications?

A: UB3C-300RF1 matches all critical electrical parameters and is mechanically compatible as an axial package. The lower maximum operating temperature of 250°C versus 275°C may be a constraint in high-temperature applications. The compact physical dimensions (4.00mm x 8.90mm) require verification of PCB layout compatibility compared to the 43F300E footprint (5.60mm x 15.10mm).

Q: What is the significance of the additional features listed for UB3C-300RF1?

A: Current sense, flame proof, moisture resistant, pulse withstanding, and safety features are supplementary characteristics of the UB3C-300RF1 design. These features do not affect basic substitution eligibility but indicate the part is engineered for demanding environments. Applications not requiring these features can still use this part as a direct substitute.

Q: Why does WW3FT300R have a higher operating temperature range?

A: WW3FT300R is rated to 350°C maximum, compared to 275°C for 43F300E and 250°C for UB3C-300RF1. This extended range reflects the design and materials used by Stackpole Electronics. For applications operating below 275°C, this extended capability provides additional thermal margin without affecting performance.

Q: Are there physical dimension constraints for substitution?

A: Yes. The three parts have different axial dimensions. The 43F300E measures 5.60mm x 15.10mm, UB3C-300RF1 measures 4.00mm x 8.90mm, and WW3FT300R measures 4.75mm x 14.22mm. PCB layout, component spacing, and thermal management considerations may restrict which part can be used in a given design. Verify board layout compatibility before substitution.

Q: Do all parts meet the same compliance standards?

A: All three parts are RoHS compliant. The 43F300E carries RoHS Compliant designation, while UB3C-300RF1 and WW3FT300R carry ROHS3 Compliant designation. Both certifications satisfy RoHS requirements. UB3C-300RF1 and WW3FT300R also carry REACH Unaffected status, providing additional regulatory documentation.