Ohmite 45J40RE Equivalent & Substitute Parts

Part Overview

The Ohmite 45J40RE is a 40 Ohm, 5% tolerance, 5W axial wirewound through-hole resistor from the Ohmicone® 40 series. This component is actively manufactured and maintained in production status. Equivalent and substitute parts are identified when component availability is limited, supply chain disruptions occur, or design requirements permit tolerance upgrades while maintaining electrical and mechanical compatibility.

Substiute Parts

45J40RE

OhmiteIn Stock: 87245J40RE Datasheet

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45F40RE

OhmiteIn Stock: 121145F40RE Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the 45J40RE is determined by the following critical parameters:

• Resistance Value: Must be 40 Ohms (exact match required)
• Power Rating: Must be 5W (exact match required)
• Package Type: Must be Axial (exact match required)
• Physical Dimensions: Must be 0.343" Dia x 0.937" L (exact match required)
• Composition: Must be Wirewound (exact match required)
• Temperature Coefficient: Must be ±20ppm/°C (exact match required)
• Tolerance: May be equal to or tighter than ±5%

The 45F40RE qualifies as a direct substitute because it maintains identical electrical specifications (40 Ohms, 5W, ±20ppm/°C), identical mechanical form factor (axial, 0.343" Dia x 0.937" L), and identical composition (wirewound). The tolerance specification of ±1% on the 45F40RE is tighter than the ±5% requirement, making it functionally compatible for any application requiring the 45J40RE.

Parameter Comparison

Engineering Selection Recommendations

The 45F40RE is a qualified substitute for the 45J40RE in all applications where the original part is specified. Selection between these parts should be based on the following criteria:

Use 45J40RE when:

• Standard tolerance of ±5% meets circuit requirements
• Cost optimization is a primary design consideration
• Existing inventory or supply agreements favor this part number

Use 45F40RE when:

• Tighter tolerance of ±1% is required for circuit performance
• Supply availability of the 45J40RE is constrained
• Design specifications permit tolerance upgrades without circuit redesign
• Long-term supply continuity is a concern

Both parts maintain active production status and comply with applicable environmental regulations (RoHS, REACH). The 45F40RE offers improved tolerance performance without any mechanical or electrical compromise to the circuit application.

Frequently Asked Questions (FAQ)

Q: Can the 45F40RE be used as a direct replacement for the 45J40RE?

A: Yes. The 45F40RE is a direct substitute. It maintains identical resistance (40 Ohms), power rating (5W), physical dimensions (0.343" Dia x 0.937" L), composition (wirewound), and temperature coefficient (±20ppm/°C). The tolerance is tighter (±1% vs. ±5%), which is compatible with any circuit designed for the 45J40RE.

Q: What is the difference between the 45J40RE and 45F40RE?

A: The primary difference is tolerance specification. The 45J40RE has ±5% tolerance, while the 45F40RE has ±1% tolerance. All other electrical and mechanical parameters are identical. The tighter tolerance of the 45F40RE makes it suitable for applications requiring higher precision resistance values.

Q: Are the physical dimensions identical between these parts?

A: Yes. Both the 45J40RE and 45F40RE share identical axial package dimensions of 0.343" Dia x 0.937" L (8.70mm x 23.80mm). They are mechanically interchangeable on PCBs and in through-hole applications.

Q: Do both parts meet RoHS compliance requirements?

A: Yes. The 45J40RE is ROHS3 Compliant, and the 45F40RE is RoHS Compliant. Both parts satisfy environmental and regulatory requirements for electronic component use.

Q: Can I substitute the 45J40RE with a lower tolerance part?

A: Yes, when the substitute maintains all other critical parameters. The 45F40RE, with its ±1% tolerance, is a valid upgrade substitute for the 45J40RE. Tighter tolerance specifications do not compromise circuit compatibility.