308NPC250K Equivalent & Substitute Parts Reference

Part Overview

The Honeywell Sensing and Productivity Solutions 308NPC250K is a 250k Ohm, 1/2W (0.5W) linear panel mount potentiometer with conductive plastic resistive material and PC pin termination. This component is classified as obsolete, making identification of functionally equivalent substitute parts essential for ongoing design support, maintenance, and production continuity. The 308NPC series is no longer in active manufacturing, necessitating evaluation of alternative components that maintain electrical and mechanical compatibility with existing applications.

Substiute Parts

308NPC250K

Honeywell Sensing and Productivity SolutionsIn Stock: 786308NPC250K Datasheet

Current PartRFQ

91A1A-B28-E22L

Bourns Inc.In Stock: 118491A1A-B28-E22L Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the 308NPC250K are identified based on strict alignment with the following critical electrical and mechanical parameters:

Electrical Compatibility Requirements:

• Resistance value: 250k Ohm (exact match)
• Tolerance: ±10% (exact match)
• Taper characteristic: Linear (exact match)
• Resistive material: Conductive Plastic (exact match)
• Number of gangs: 1 (exact match)
• Termination style: PC Pins (exact match)

Mechanical Compatibility Requirements:

• Mounting type: Panel Mount (exact match)
• Adjustment type: Side Adjustment (exact match)
• Actuator type: Slotted (exact match)
• Number of turns: 1.0 (exact match)

Allowable Variations:

• Power rating: Substitute may equal or exceed the 0.5W specification
• Rotation angle: Substitute may equal or exceed 295° specification
• Physical dimensions: Substitute body size may differ provided panel mount bushing thread compatibility is maintained
• Regulatory compliance: Substitute must maintain RoHS compliance or higher standard

The 91A1A-B28-E22L from Bourns Inc. meets all critical electrical parameters and mechanical mounting requirements, with allowable variations in power rating (1W vs. 0.5W) and rotation angle (300° vs. 295°).

Parameter Comparison

Engineering Selection Recommendations

Primary Substitute: Bourns 91A1A-B28-E22L

The 91A1A-B28-E22L is the qualified substitute for the obsolete 308NPC250K based on the following engineering criteria:

Electrical Equivalence: All critical electrical parameters match exactly: 250k Ohm resistance, ±10% tolerance, linear taper, conductive plastic construction, and single-gang configuration. The 1W power rating of the substitute exceeds the 0.5W requirement of the original part, providing enhanced thermal margin in the application.

Mechanical Compatibility: Panel mount configuration, side adjustment mechanism, slotted actuator type, and PC pin termination are identical. The 300° rotation specification of the substitute exceeds the 295° requirement, maintaining functional compatibility.

Regulatory Compliance: The 91A1A-B28-E22L carries ROHS3 compliance, which supersedes the RoHS compliance of the original 308NPC250K. This upgrade ensures continued compliance with current environmental regulations.

Production Status: The substitute is in active production with confirmed inventory availability (1115 pcs), ensuring supply chain continuity for new builds and field replacements.

Physical Integration: While body dimensions differ (rectangular 0.687" x 0.625" vs. square 0.500" x 0.500"), both components use panel mount configuration with threaded bushings. Mechanical integration requires verification of panel cutout dimensions and available mounting space in the target application.

Frequently Asked Questions (FAQ)

Q: Can the 91A1A-B28-E22L directly replace the 308NPC250K in existing designs?

A: Electrical and functional substitution is valid based on matching resistance, tolerance, taper, material, and termination specifications. Mechanical integration requires verification of panel mounting space and bushing thread compatibility (1/4-32 vs. 3/8-32). Physical dimensions differ, necessitating panel layout review.

Q: Why does the substitute have a higher power rating (1W vs. 0.5W)?

A: Higher power ratings provide thermal design margin and do not compromise application performance. The substitute will operate safely in circuits designed for 0.5W potentiometers. This is an allowable variation that enhances component reliability.

Q: Are there differences in rotation angle between the parts?

A: The substitute provides 300° rotation versus 295° for the original. This 5° difference is within acceptable tolerance for linear potentiometer applications and does not affect functional compatibility.

Q: What is the significance of ROHS3 compliance on the substitute?

A: ROHS3 represents current environmental compliance standards and supersedes the RoHS compliance of the obsolete 308NPC250K. Selection of the substitute ensures ongoing regulatory compliance for new production and field service applications.

Q: Are the PC pin terminations identical between parts?

A: Both components use PC pin termination style, ensuring electrical connection compatibility. Pin spacing and configuration must be verified against the specific PCB design to confirm mechanical fit.

Q: What packaging differences exist between the parts?

A: The 308NPC250K is supplied in standard packaging, while the 91A1A-B28-E22L is supplied in Tray packaging. This difference affects handling and storage procedures but does not impact component performance or electrical characteristics.

Q: Can the substitute be used in high-temperature applications?

A: The substitute specifies a temperature coefficient of ±1000ppm/°C. Temperature performance must be evaluated against specific application requirements and operating environment conditions.