GS202F1K Equivalent & Substitute Parts

Part Overview

The GS202F1K is an NTC thermistor manufactured by Littelfuse Inc., designed for temperature sensing applications. This component features a 2kΩ resistance at 25°C with a B25/85 value of 3470K, housed in a glass bead package with 1.00" lead wire length. The product is currently classified as obsolete, making identification of suitable equivalent parts essential for ongoing system support and component procurement.

Substiute Parts

GS202F1K

Littelfuse Inc.In Stock: 1065GS202F1K Datasheet

Current PartRFQ

121-202EAJ-Q01

Honeywell Sensing and Productivity SolutionsIn Stock: 1052121-202EAJ-Q01 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the GS202F1K is determined by the following critical parameters:

• Resistance value at 25°C: 2kΩ (primary electrical characteristic)
• B-value at 25°C/85°C: 3470K (thermal response characteristic)
• Operating temperature capability: 300°C maximum
• Package configuration: Glass construction for thermal stability
• Lead wire length and mounting compatibility

The substitute part 121-202EAJ-Q01 meets these core electrical requirements with a matching 2kΩ resistance and B25/85 value of 3518K, which falls within acceptable thermal response parameters for NTC thermistor applications. Both components operate to 300°C and utilize glass construction.

Parameter Comparison

Engineering Selection Recommendations

The 121-202EAJ-Q01 serves as an active substitute for the obsolete GS202F1K based on electrical equivalence and product availability. Both components share identical 2kΩ resistance specifications and comparable B-value thermal characteristics (3470K vs. 3518K), ensuring functional compatibility in temperature sensing circuits.

The substitute part offers extended temperature range capability (-60°C to 300°C versus 300°C maximum for the original), RoHS compliance certification, and active product status with confirmed inventory availability. The cylindrical probe package and extended 2.00" lead wire length differ from the original bead configuration and 1.00" leads, requiring mechanical integration assessment for specific applications.

Frequently Asked Questions (FAQ)

Q: Can the 121-202EAJ-Q01 directly replace the GS202F1K in existing designs?

A: Electrical substitution is valid based on matching 2kΩ resistance and comparable B-value specifications. Mechanical compatibility must be verified, as the substitute features a cylindrical probe package with 2.00" leads versus the original bead package with 1.00" leads. Circuit board layout and mounting provisions require review.

Q: What is the significance of the B25/85 value difference (3470K vs. 3518K)?

A: The B-value defines the thermistor's thermal response curve. The 1.4% difference between 3470K and 3518K represents acceptable variation within NTC thermistor manufacturing tolerances and does not preclude functional substitution in standard temperature sensing applications.

Q: Does the resistance tolerance difference (±10% vs. ±20%) affect substitution suitability?

A: The substitute part carries wider tolerance specification. Applications requiring tighter resistance accuracy should evaluate whether the ±20% tolerance of the 121-202EAJ-Q01 meets circuit design requirements. Both components operate within the 2kΩ nominal specification.

Q: What are the implications of the different mounting types?

A: The GS202F1K uses through-hole mounting for PCB integration, while the 121-202EAJ-Q01 is configured for free-hanging installation. Physical mounting method must be adapted to the application's mechanical design. Lead wire length also differs (1.00" vs. 2.00"), affecting installation routing and thermal coupling considerations.

Q: Is RoHS compliance a factor in selecting the substitute?

A: The 121-202EAJ-Q01 carries RoHS Compliant certification, which may be required for applications subject to RoHS regulations. The original GS202F1K does not specify RoHS status. Regulatory requirements for the target application should be confirmed.