Ohmite 45J300 300 Ohm 5W Axial Wirewound Resistor - Equivalent & Substitute Parts

Part Overview

The Ohmite 45J300 is a 300 Ohm, 5% tolerance, 5W through-hole axial wirewound resistor from the Ohmicone® 40 series. This component is designed for applications requiring precision power dissipation in compact axial form factor. The part is currently active in production with 1062 units in stock. Equivalent and substitute parts are identified to support procurement flexibility, inventory management, and design continuity when the primary part becomes unavailable or when alternative compliance certifications are required.

Substiute Parts

45J300

OhmiteIn Stock: 112145J300 Datasheet

Current PartRFQ

45J300E

OhmiteIn Stock: 93645J300E Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the Ohmite 45J300 are identified based on strict parametric equivalence across all critical electrical and mechanical specifications. The substitution logic is based on the following key parameters:

• Resistance Value: 300 Ohms (exact match required)
• Tolerance: ±5% (exact match required)
• Power Rating: 5W (exact match required)
• Composition: Wirewound (exact match required)
• Package Type: Axial (exact match required)
• Temperature Coefficient: ±20ppm/°C (exact match required)
• Physical Dimensions: 0.343" Dia x 0.937" L / 8.70mm x 23.80mm (exact match required)
• Termination Count: 2 (exact match required)

The substitute part 45J300E meets all these criteria and is therefore a direct parametric equivalent. Differences in RoHS compliance status do not affect electrical or mechanical interchangeability.

Parameter Comparison

Engineering Selection Recommendations

Both the Ohmite 45J300 and 45J300E are active production parts with identical electrical and mechanical specifications. Selection between these parts should be based on regulatory and compliance requirements:

• 45J300: Select this part for applications where RoHS non-compliance is acceptable or where legacy component specifications are required.
• 45J300E: Select this part for applications requiring ROHS3 compliance or for new designs targeting modern regulatory standards.

Both parts carry identical REACH Unaffected and EAR99 export classification status. Inventory availability should be considered as a secondary factor in part selection, with 45J300 currently showing higher stock levels (1062 units versus 917 units).

Frequently Asked Questions (FAQ)

Q: Are the 45J300 and 45J300E electrically interchangeable?

A: Yes. Both parts have identical resistance (300 Ohms), tolerance (±5%), power rating (5W), temperature coefficient (±20ppm/°C), and composition (wirewound). They are direct electrical equivalents.

Q: Are the 45J300 and 45J300E mechanically interchangeable?

A: Yes. Both parts share identical physical dimensions (0.343" Dia x 0.937" L / 8.70mm x 23.80mm), axial package type, and two-terminal configuration. They are direct mechanical equivalents and can be used interchangeably in PCB layouts and through-hole applications.

Q: What is the difference between 45J300 and 45J300E?

A: The primary difference is RoHS compliance status. The 45J300 is RoHS non-compliant, while the 45J300E is ROHS3 compliant. All other electrical, mechanical, and regulatory parameters are identical.

Q: Which part should I specify for a new design?

A: Specify based on your application's regulatory requirements. For designs requiring ROHS3 compliance, use 45J300E. For applications without RoHS requirements, either part is acceptable based on availability and cost considerations.

Q: Can I use 45J300E as a drop-in replacement for 45J300 in existing designs?

A: Yes. The 45J300E is a direct parametric equivalent and can be used as a drop-in replacement without circuit modifications or re-qualification, provided your application does not have specific restrictions against ROHS3-compliant components.

Q: Are there any thermal or frequency limitations I should consider?

A: Both parts operate within the same temperature coefficient range (±20ppm/°C) and power dissipation envelope (5W). No additional thermal or frequency derating is required when substituting between these parts.