308NPC50K Equivalent & Substitute Parts Reference

Part Overview

The Honeywell 308NPC50K is a 50k Ohm 1/2W conductive plastic linear panel mount potentiometer with PC pin termination, designed for side adjustment applications. This component features a 1-gang configuration with 295° rotation and a slotted actuator. The product is currently obsolete, necessitating identification of functionally equivalent alternatives for ongoing maintenance and new design applications.

Substiute Parts

308NPC50K

Honeywell Sensing and Productivity SolutionsIn Stock: 913308NPC50K Datasheet

Current PartRFQ

51CAD-E24-B18L

Bourns Inc.In Stock: 96551CAD-E24-B18L Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the 308NPC50K is based on strict alignment of the following critical parameters:

Mandatory Matching Parameters:

• Resistance value: 50k Ohm
• Power rating: 0.5W / 1/2W minimum
• Taper type: Linear
• Number of gangs: 1
• Termination style: PC Pins
• Mounting type: Panel Mount
• Bushing thread: 1/4-32
• Resistive material: Conductive Plastic

Allowable Variations:

• Tolerance: May differ (±10% vs ±20%)
• Rotation angle: Minor variations acceptable (295° vs 290°)
• Body dimensions: Minor variations acceptable within panel mount constraints
• Temperature coefficient: May vary if not specified in original design
• Product status: Active products preferred for obsolete components

The Bourns 51CAD-E24-B18L meets all mandatory matching parameters and is classified as an equivalent substitute.

Parameter Comparison

Engineering Selection Recommendations

Primary Substitute: Bourns 51CAD-E24-B18L

The 51CAD-E24-B18L is the qualified equivalent substitute for the obsolete 308NPC50K based on the following engineering criteria:

1. Functional Equivalence: All critical electrical parameters match exactly (50k Ohm, 0.5W/1/2W, linear taper, 1-gang configuration).

2. Mechanical Compatibility: Identical bushing thread (1/4-32), actuator dimensions (0.750" length, 0.125" diameter), and mounting type ensure direct panel mount compatibility.

3. Termination Compatibility: PC pin termination matches the original design, enabling direct PCB connection without adapter requirements.

4. Compliance Status: The substitute maintains RoHS3 compliance and is REACH affected, meeting current regulatory requirements. The original component's RoHS compliance is superseded by the substitute's ROHS3 status.

5. Production Availability: Active product status ensures long-term supply chain continuity, addressing the obsolescence of the original component.

6. Minor Parameter Variations: The 5° rotation difference (290° vs 295°) and ±20% tolerance (vs ±10%) are within acceptable engineering margins for potentiometer applications. Body dimension variations (rectangular vs square) remain within panel mount constraints.

7. Additional Features: The substitute includes sealed construction, providing enhanced environmental protection compared to the original specification.

Frequently Asked Questions (FAQ)

Q: Can the 51CAD-E24-B18L be used as a direct replacement for the 308NPC50K without circuit modifications?

A: Yes. The substitute matches all critical electrical and mechanical parameters. Direct substitution is possible without circuit redesign. The 5° rotation difference and tolerance variation do not require circuit modification for standard potentiometer applications.

Q: What is the significance of the tolerance difference (±10% vs ±20%)?

A: The original 308NPC50K specifies ±10% tolerance, while the 51CAD-E24-B18L specifies ±20%. For applications requiring tighter tolerance control, the substitute's wider tolerance range must be evaluated against circuit requirements. The substitute will still function within the original design parameters in most applications.

Q: Are the body dimension differences (square vs rectangular) a concern for panel mounting?

A: The dimension variations are minor (0.500" vs 0.521" width, 0.500" vs 0.492" height). Both components use identical 1/4-32 bushing threads and fit standard panel mount openings. Verify panel cutout dimensions in your specific application to confirm fit.

Q: Why is the 51CAD-E24-B18L listed as "Active" while the 308NPC50K is "Obsolete"?

A: The 308NPC50K has been discontinued by Honeywell. The 51CAD-E24-B18L is current production from Bourns, ensuring ongoing availability for new designs and replacement applications. Using an active product eliminates future obsolescence risk.

Q: Does the sealed construction of the 51CAD-E24-B18L affect performance compared to the original?

A: Sealed construction provides enhanced environmental protection and durability. This is a functional improvement that does not negatively impact performance. The sealed design may extend component life in applications with moisture or contamination exposure.

Q: Are there any compliance or certification differences between the two components?

A: Both components are RoHS compliant. The substitute carries ROHS3 compliance (current standard) and is REACH affected. The original component's RoHS compliance status is superseded by the substitute's more current ROHS3 certification, meeting modern regulatory requirements.

Q: What is the impact of the temperature coefficient specification on the substitute?

A: The 51CAD-E24-B18L specifies ±1000ppm/°C temperature coefficient, while the original does not provide this specification. This coefficient indicates resistance change over temperature range. For applications with strict temperature stability requirements, verify that ±1000ppm/°C meets your design specifications.