850F40R Equivalent & Substitute Parts

Part Overview

The Ohmite 850F40R is a 40 Ohms ±1% 50W wirewound chassis mount resistor from the Metal-Mite®89 series. This component is classified as obsolete, making identification of functionally equivalent alternatives essential for ongoing system support and new design implementations. The 850F40R features aluminum housing with flanged mounting and solder lug termination, designed for applications requiring precision resistance with high power dissipation in compact form factors.

Substiute Parts

850F40R

OhmiteIn Stock: 984850F40R Datasheet

Current PartRFQ

850F40RE

OhmiteIn Stock: 924850F40RE Datasheet

DirectRFQ

RH05040R00FC02

Vishay DaleIn Stock: 1046RH05040R00FC02 Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the 850F40R is determined by strict equivalence across the following critical parameters:

• Resistance value: 40 Ohms
• Tolerance: ±1%
• Power rating: 50W
• Composition: Wirewound
• Temperature coefficient: ±20ppm/°C
• Housing material: Aluminum
• Mounting configuration: Flanged
• Termination style: Solder lugs
• Package format: Axial, Box

Two substitute parts meet these criteria: the Ohmite 850F40RE and the Vishay Dale RH05040R00FC02. Both maintain identical electrical specifications and mechanical mounting interfaces, enabling direct functional replacement in applications originally designed for the 850F40R.

Parameter Comparison

Engineering Selection Recommendations

The Ohmite 850F40RE represents the primary substitute for the obsolete 850F40R. Both components are manufactured by Ohmite and share identical electrical and mechanical specifications. The 850F40RE maintains active product status and achieves ROHS3 compliance, making it suitable for applications subject to RoHS regulations.

The Vishay Dale RH05040R00FC02 provides an alternative from a different manufacturer. This component maintains all critical electrical parameters and mechanical interfaces. The maximum operating temperature is limited to 250°C compared to 275°C for the Ohmite variants, which may affect suitability in high-temperature applications. The RH05040R00FC02 is subject to REACH regulations, requiring compliance verification for specific end-use applications.

Selection between the two substitutes depends on regulatory requirements, supply chain preferences, and thermal operating conditions specific to the application.

Frequently Asked Questions (FAQ)

Q: Can the 850F40RE directly replace the 850F40R without circuit modification?

A: Yes. The 850F40RE maintains identical resistance, tolerance, power rating, temperature coefficient, and mechanical mounting configuration. Direct substitution is functionally equivalent.

Q: What is the primary difference between the 850F40R and its substitutes?

A: The 850F40R is obsolete. The 850F40RE is the active Ohmite equivalent with improved RoHS3 compliance. The Vishay Dale RH05040R00FC02 offers cross-manufacturer compatibility with a reduced maximum operating temperature of 250°C.

Q: Are there dimensional differences between these parts?

A: The 850F40R and 850F40RE share identical dimensions: 1.938" L × 1.156" W (49.23mm × 29.36mm) with 0.620" (15.75mm) seated height. The RH05040R00FC02 has minor dimensional variations: 1.968" L × 1.140" W (49.99mm × 28.96mm) with 0.625" (15.87mm) seated height. These variations remain within typical PCB layout tolerances for flanged chassis mount resistors.

Q: Which substitute is recommended for new designs?

A: Selection depends on regulatory and thermal requirements. For RoHS3-compliant applications, the Ohmite 850F40RE is recommended. For applications operating below 250°C without RoHS requirements, the Vishay Dale RH05040R00FC02 provides cross-manufacturer redundancy.

Q: What packaging formats are available for these substitutes?

A: The 850F40RE is supplied in bulk packaging. The RH05040R00FC02 is also supplied in bulk packaging. Both maintain the axial, box package format compatible with the original 850F40R.