KW503R2 Equivalent & Substitute Parts

Part Overview

The KW503R2 is an NTC thermistor manufactured by Littelfuse Inc., featuring a 50kΩ resistance at 25°C with a B value of 4140K. This component is classified as a temperature sensor in bead form with epoxy packaging and free-hanging mounting configuration. The product is currently obsolete, making identification of suitable substitute components essential for ongoing applications and system maintenance.

Substiute Parts

KW503R2

Littelfuse Inc.In Stock: 749KW503R2 Datasheet

Current PartRFQ

192-503QET-A01

Honeywell Sensing and Productivity SolutionsIn Stock: 2155192-503QET-A01 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the KW503R2 is determined by the following critical parameters:

• Resistance Value: 50kΩ at 25°C (primary electrical characteristic)
• B Value: Thermal sensitivity coefficient (4140K nominal range acceptable)
• Lead Wire Length: 1.50" (38.00mm) for mechanical fit
• Package Type: Bead configuration for form factor compatibility
• Operating Temperature Range: Minimum 120°C upper limit requirement
• Power Dissipation: 30 mW maximum rating
• Compliance: RoHS and REACH status for regulatory alignment

The substitute part 192-503QET-A01 meets these criteria with equivalent electrical characteristics and compatible mechanical specifications.

Parameter Comparison

Engineering Selection Recommendations

The 192-503QET-A01 from Honeywell Sensing and Productivity Solutions is a direct functional equivalent for the obsolete KW503R2. Both components share identical 50kΩ resistance values and equivalent B values (4140K vs. 4138K), with B value variance of 2K representing negligible thermal response deviation in practical applications.

The substitute part provides extended operating temperature range (-60°C to 150°C) compared to the original specification (120°C maximum), offering improved thermal margin for applications requiring higher temperature tolerance. Both components maintain identical lead wire length (1.50" / 38.00mm) for mechanical compatibility.

RoHS and REACH compliance status is maintained with the substitute part, ensuring regulatory alignment. The 192-503QET-A01 is currently in active production status, providing supply continuity and long-term availability compared to the obsolete KW503R2.

Frequently Asked Questions (FAQ)

Q: Can the 192-503QET-A01 be used as a direct replacement for the KW503R2?

A: Yes. Both components feature 50kΩ resistance at 25°C with equivalent B values (4140K vs. 4138K). Lead wire length and bead package configuration are identical, supporting direct mechanical and electrical substitution.

Q: What is the significance of the B value difference (4140K vs. 4138K)?

A: The 2K difference represents a 0.05% variance in thermal sensitivity coefficient. This difference is within acceptable tolerance for most temperature sensing applications and does not require circuit recalibration.

Q: Does the extended operating temperature range of the 192-503QET-A01 affect compatibility?

A: No. The extended range (-60°C to 150°C) provides additional thermal capability without affecting performance within the original KW503R2 operating envelope (up to 120°C).

Q: Are there packaging differences between these components?

A: The KW503R2 specifies epoxy bead packaging with free-hanging mounting, while the 192-503QET-A01 uses standard bead packaging with through-hole mounting capability. Both configurations support the same electrical function and mechanical form factor.

Q: Is the 192-503QET-A01 currently available?

A: Yes. The 192-503QET-A01 maintains active product status with current inventory availability, providing reliable supply for new designs and replacement applications.