PT503R2 NTC Thermistor 50kΩ Equivalent & Substitute Parts

Part Overview

The PT503R2 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 PT503R2 is currently listed as obsolete, making identification of functionally equivalent substitute parts essential for ongoing design support and component procurement.

Substiute Parts

PT503R2

Littelfuse Inc.In Stock: 966PT503R2 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 PT503R2 is determined by the following critical electrical and mechanical parameters:

• Resistance value at 25°C: 50kΩ (primary electrical specification)
• B value (B0/50): 4140K ± tolerance (thermal response characteristic)
• Lead wire length: 1.50" (38.00mm) (mechanical compatibility)
• Package form: Bead configuration (physical form factor)
• Operating temperature range: Minimum 120°C upper limit required
• Power dissipation: 30 mW maximum rating
• Regulatory compliance: RoHS and REACH status

The substitute part 192-503QET-A01 meets these criteria with matching resistance, comparable B value, identical lead length, and compatible bead packaging. Both components share equivalent regulatory compliance classifications.

Parameter Comparison

Engineering Selection Recommendations

The 192-503QET-A01 from Honeywell Sensing and Productivity Solutions is a direct functional substitute for the obsolete PT503R2. Both components share identical resistance specifications at 25°C and equivalent B value characteristics within stated tolerances. The substitute part maintains the same lead wire length and bead package form factor, ensuring mechanical compatibility in existing designs.

The 192-503QET-A01 offers an extended operating temperature range (-60°C to 150°C) compared to the PT503R2 (up to 120°C), providing additional thermal margin for applications. Both components maintain equivalent regulatory compliance status under RoHS and REACH requirements, with MSL rating of 1 (Unlimited moisture sensitivity level).

Selection of the 192-503QET-A01 is supported by active product status and confirmed inventory availability, eliminating supply chain risk associated with the obsolete PT503R2.

Frequently Asked Questions (FAQ)

Q: What makes the 192-503QET-A01 a suitable substitute for the PT503R2?

A: Both components share the same 50kΩ resistance at 25°C, equivalent B values (4140K vs. 4138K, within ±2.1% tolerance), identical lead wire length (1.50"), and compatible bead package configurations. Regulatory compliance and moisture sensitivity ratings are equivalent.

Q: Are there differences in the B value between these parts?

A: The PT503R2 specifies a B value of 4140K, while the 192-503QET-A01 specifies 4138K. This 2K difference represents approximately 0.05% variance and falls within the ±2.1% B value tolerance of the substitute part, ensuring thermal response compatibility.

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

A: No. The substitute part's operating range of -60°C to 150°C exceeds the PT503R2 requirement of 120°C maximum. This provides additional thermal margin without compromising electrical characteristics within the original design envelope.

Q: Are the package forms identical?

A: Both components use bead package configurations with identical lead wire lengths. The PT503R2 specifies epoxy bead packaging, while the 192-503QET-A01 specifies bead packaging. These are mechanically compatible for through-hole and free-hanging mounting applications.

Q: What is the regulatory compliance status of the substitute part?

A: The 192-503QET-A01 maintains RoHS compliance and REACH unaffected status, matching the regulatory requirements of the PT503R2. Both components carry MSL rating 1 (Unlimited), indicating no moisture sensitivity restrictions.