Bourns 3386U-1-503 Trimmer Potentiometer: Equivalent & Substitute Parts

Part Overview

The Bourns 3386U-1-503 is a 50 kOhm, 0.5W through-hole trimmer potentiometer with PC pin termination and top adjustment. This sealed Trimpot® 3386 series component is designed for applications requiring precision resistance adjustment in compact form factors. The part is currently active in production. Equivalent and substitute parts are identified based on matching electrical specifications, mechanical compatibility, and functional performance within the allowed parameter tolerances for this product category.

Substiute Parts

3386U-1-503

Bourns Inc.In Stock: 11093386U-1-503 Datasheet

Current PartRFQ

25PR50KLF

TT Electronics/BIIn Stock: 1166425PR50KLF Datasheet

SimilarRFQ

72PR50KLF

TT Electronics/BIIn Stock: 140172PR50KLF Datasheet

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82PR50KLF

TT Electronics/BIIn Stock: 110082PR50KLF Datasheet

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M63P503KB40

Vishay SpectrolIn Stock: 1143M63P503KB40 Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the 3386U-1-503 are qualified based on the following critical parameters:

• Electrical Match: Resistance value (50 kOhms), power rating (0.5W), tolerance (±10%), and temperature coefficient (±100ppm/°C) must be identical
• Functional Match: Number of turns (1), resistive material (Cermet), and termination style (PC Pins) must be identical
• Mechanical Compatibility: Mounting type (Through Hole) and form factor must accommodate the same PCB layout
• Adjustment Type Consideration: Top adjustment is the primary specification; side adjustment variants are listed but require circuit board redesign

Three primary substitute groups are identified:

Group 1 - Direct Footprint Equivalents (Square 0.375" x 0.375")

• TT Electronics/BI 72PR50KLF (Series 72, Bulk packaging)

Group 2 - Compact Footprint Alternative (Square 0.270" x 0.270")

• TT Electronics/BI 25PR50KLF (Series 25, Tube packaging)

Group 3 - Round Footprint Alternative (0.250" Dia)

• TT Electronics/BI 82PR50KLF (Series 82, Bulk packaging)

Group 4 - Side Adjustment Variant (Square 0.395" x 0.395")

• Vishay Spectrol M63P503KB40 (Series 63, Side Adjustment)

Parameter Comparison

Engineering Selection Recommendations

For Direct Replacement (No PCB Redesign)

The TT Electronics/BI 72PR50KLF is the primary substitute for the 3386U-1-503. Both parts share identical electrical specifications, the same square footprint (0.375" x 0.375"), top adjustment configuration, and PC pin termination. The 72PR50KLF offers ROHS3 compliance and is available in bulk packaging with 1,341 units in stock.

For Space-Constrained Designs

The TT Electronics/BI 25PR50KLF provides all electrical equivalence with a reduced footprint (0.270" x 0.270" square). This compact variant is suitable for applications where board space is limited. The 25PR50KLF is RoHS compliant and available in tube packaging with 11,557 units in stock.

For Round Footprint Requirements

The TT Electronics/BI 82PR50KLF maintains full electrical equivalence with a round form factor (0.250" diameter). This variant is applicable to designs requiring circular mounting patterns. The 82PR50KLF is ROHS3 compliant and available in bulk packaging with 1,017 units in stock.

For Side Adjustment Applications

The Vishay Spectrol M63P503KB40 provides electrical equivalence with side adjustment instead of top adjustment. This part requires circuit board redesign to accommodate the different adjustment orientation and larger footprint (0.395" x 0.395" square). The M63P503KB40 is ROHS3 compliant with 1,074 units in stock.

Frequently Asked Questions (FAQ)

Q: Can the 25PR50KLF be used as a direct replacement for the 3386U-1-503?

A: The 25PR50KLF is electrically equivalent but has a smaller footprint (0.270" x 0.270" versus 0.375" x 0.375"). It can be used if the PCB layout accommodates the reduced size. The adjustment mechanism and termination style are identical.

Q: What is the difference between the 72PR50KLF and 82PR50KLF?

A: Both parts are electrically identical to the 3386U-1-503. The primary difference is the form factor: the 72PR50KLF has a square footprint matching the original part (0.375" x 0.375"), while the 82PR50KLF has a round footprint (0.250" diameter). Selection depends on PCB mounting pattern requirements.

Q: Why is the M63P503KB40 listed as a substitute if it has side adjustment instead of top adjustment?

A: The M63P503KB40 is electrically and functionally equivalent but requires circuit board redesign due to the different adjustment orientation. It is included as an alternative for applications where side adjustment is acceptable or preferred.

Q: Are all substitute parts RoHS compliant?

A: The original 3386U-1-503 is RoHS non-compliant. The TT Electronics/BI substitutes (25PR50KLF, 72PR50KLF, 82PR50KLF) and the Vishay Spectrol M63P503KB40 are all RoHS compliant or ROHS3 compliant, making them suitable for applications with RoHS requirements.

Q: Can I use the 25PR50KLF in a design originally specified for the 3386U-1-503?

A: Yes, provided the PCB layout can accommodate the smaller footprint. All electrical parameters, adjustment type, and termination style are identical. Verify that the reduced size does not conflict with surrounding components or mechanical constraints.

Q: What packaging options are available for these substitutes?

A: The 25PR50KLF is available in tube packaging. The 72PR50KLF, 82PR50KLF, and M63P503KB40 are available in bulk packaging. Packaging selection depends on production volume and handling requirements.