Ohmite 40J300 Equivalent & Substitute Parts

Part Overview

The Ohmite 40J300 is a 300 Ohm, 5% tolerance, 10W axial wirewound through-hole resistor from the Ohmicone® 40 series. This component is classified as Active product status and is suitable for applications requiring precision power dissipation in compact form factors. Substitute parts are identified when equivalent electrical specifications and mechanical compatibility are maintained across the same product category, enabling procurement flexibility and supply chain continuity.

Substiute Parts

40J300

OhmiteIn Stock: 79440J300 Datasheet

Current PartRFQ

40J300E

OhmiteIn Stock: 131940J300E Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the 40J300 is determined by strict equivalence across the following critical parameters:

• Resistance value: 300 Ohms (exact match required)
• Tolerance: ±5% (exact match required)
• Power rating: 10W (exact match required)
• Composition: Wirewound (exact match required)
• Package type: Axial (exact match required)
• Temperature coefficient: ±20ppm/°C (exact match required)
• Physical dimensions: 0.406" Dia x 1.902" L (exact match required)

The 40J300E meets all substitution criteria as a parametric equivalent within the Ohmicone® 40 series, differing only in packaging configuration (Bulk versus standard packaging) and compliance certifications.

Parameter Comparison

Engineering Selection Recommendations

Both the 40J300 and 40J300E are Active status components from Ohmite's Ohmicone® 40 series with identical electrical and mechanical specifications. Selection between these parts should be based on compliance requirements and packaging needs:

The 40J300E is ROHS3 compliant and REACH unaffected, making it suitable for applications subject to environmental regulations. The 40J300 is RoHS non-compliant and should be selected only when legacy compliance status is acceptable or required by design specifications.

Packaging configuration differs between the two parts: the 40J300 uses standard packaging while the 40J300E is supplied in Bulk packaging. Inventory availability is 704 pieces for the 40J300 and 1211 pieces for the 40J300E.

Frequently Asked Questions (FAQ)

Q: Can the 40J300E replace the 40J300 in all applications?

A: The 40J300E is electrically and mechanically equivalent to the 40J300. Substitution is valid from a component performance standpoint. However, the 40J300E carries ROHS3 compliance while the 40J300 does not. Verify that your application or regulatory environment permits the use of ROHS3 compliant components before substitution.

Q: What is the difference between the 40J300 and 40J300E?

A: The parts are identical in electrical specifications (300 Ohms, ±5%, 10W), composition (Wirewound), package type (Axial), and physical dimensions (0.406" Dia x 1.902" L). The differences are packaging configuration (Standard versus Bulk) and RoHS compliance status (non-compliant versus ROHS3 compliant).

Q: Are there any mechanical compatibility concerns when substituting the 40J300E for the 40J300?

A: No. Both parts share identical physical dimensions of 0.406" Dia x 1.902" L (10.30mm x 48.30mm), axial package type, and two terminations. PCB footprints and mounting requirements are identical.

Q: Which part should I select for new designs?

A: Selection depends on compliance requirements. For applications requiring ROHS3 compliance, select the 40J300E. For legacy systems or applications where RoHS compliance is not mandated, either part is suitable based on availability and procurement preferences.

Q: What certifications apply to these parts?

A: Both parts carry ECCN EAR99 classification and HTSUS code 8533.21.0080. The 40J300E is ROHS3 compliant and REACH unaffected. The 40J300 is RoHS non-compliant and REACH unaffected. Moisture sensitivity level is not applicable for both parts.