Ohmite F10J25R Wirewound Chassis Mount Resistor – Equivalent & Substitute Parts

Part Overview

The Ohmite F10J25R is a 25 Ohms ±5% 10W wirewound chassis mount resistor from the Stackohm® 250 series. This component is designed for high-power applications requiring stable resistance values across extended temperature ranges. The part is currently active in production with 656 units in stock. Substitute parts are identified when design requirements necessitate increased power dissipation capability or when inventory constraints require alternative sourcing from the same manufacturer and series.

Substiute Parts

F10J25R

OhmiteIn Stock: 731F10J25R Datasheet

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F20J25R

OhmiteIn Stock: 828F20J25R Datasheet

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Key Parameters

Substitute Part Grouping Explanation

The F10J25R has one identified substitute within the Stackohm® 250 series: the F20J25R. Substitution eligibility is determined by the following criteria:

Mandatory matching parameters:

• Resistance value: 25 Ohms
• Tolerance: ±5%
• Composition: Wirewound
• Temperature Coefficient: ±260ppm/°C
• Operating Temperature Range: -55°C to 350°C
• Coating/Housing Type: Vitreous Enamel Coated
• Mounting Feature: Flange Braces, Right Angle
• Lead Style: Solder Lugs
• Package/Case: Radial, Flat Oval
• Manufacturer: Ohmite
• Series: Stackohm® 250

Variable parameter allowing substitution:

• Power Rating: The F20J25R provides 20W capability versus the 10W of the F10J25R, enabling use in higher power dissipation applications while maintaining all other electrical and mechanical specifications.

Parameter Comparison

Engineering Selection Recommendations

Both the F10J25R and F20J25R are active production components with identical compliance profiles. Selection between these parts is determined by application power requirements:

Select F10J25R when:

• Circuit design specifies 10W maximum power dissipation
• PCB layout constraints limit component size to 0.750" length
• Inventory availability of the primary specification is confirmed

Select F20J25R when:

• Application requires 20W power dissipation capability
• PCB layout accommodates the extended 2.000" length dimension
• Higher power margin is required for thermal stability
• Inventory of the primary specification is unavailable

Both parts maintain identical electrical characteristics, temperature performance, and regulatory compliance. The dimensional difference reflects the increased thermal mass required for the higher power rating. Physical mounting verification is necessary when substituting due to the length increase from 0.750" to 2.000".

Frequently Asked Questions (FAQ)

Q: Can the F20J25R be used as a direct replacement for the F10J25R?

A: The F20J25R is electrically compatible with the F10J25R in all parameters except power rating and physical length. Substitution is valid only when the application power requirement does not exceed 20W and the PCB layout accommodates the 2.000" length dimension. The mounting feature (Flange Braces, Right Angle) remains identical.

Q: What is the primary difference between these two parts?

A: The F20J25R provides double the power rating (20W versus 10W) and is physically longer (2.000" versus 0.750") to accommodate increased thermal dissipation capability. All electrical specifications, including resistance, tolerance, temperature coefficient, and operating range, are identical.

Q: Are there any compliance or regulatory differences between F10J25R and F20J25R?

A: No. Both parts share identical RoHS status (non-compliant), REACH status (Unaffected), ECCN (EAR99), and HTSUS classification (8533.21.0080).

Q: What happens if I use the F10J25R in an application requiring 20W dissipation?

A: The F10J25R is rated for 10W maximum. Operating beyond this specification will result in excessive temperature rise and potential component failure. The F20J25R must be used for 20W applications.

Q: Can the F10J25R be used in place of the F20J25R?

A: No. The F10J25R has a lower power rating and cannot safely handle 20W dissipation. Substitution in the reverse direction is not permitted.

Q: Are the mounting dimensions compatible between these parts?

A: The height and width dimensions are identical (0.375" height, 0.375" width). The length differs: F10J25R is 0.750" while F20J25R is 2.000". PCB layout must be verified to accommodate the longer component when upgrading to the F20J25R.