Littelfuse 20101250021 Glass Cartridge Fuse 125mA 250VAC 5x20mm Equivalent & Substitute Parts

Part Overview

The Littelfuse 20101250021 is a 125mA 250VAC glass cartridge fuse with 5mm x 20mm dimensions, designed for circuit protection in AC/DC applications. This part carries an obsolete product status, making identification of active equivalent alternatives essential for ongoing procurement and system maintenance. The fuse requires a holder for installation and operates across a temperature range of -25°C to 70°C with medium blow response characteristics.

Substiute Parts

20101250021

LittelfuseIn Stock: 120320101250021 Datasheet

Current PartRFQ

20101250021P

Littelfuse Inc.In Stock: 87720101250021P Datasheet

DirectRFQ

20101250001

Littelfuse Inc.In Stock: 85720101250001 Datasheet

Parametric EquivalentRFQ

20101250001P

Littelfuse Inc.In Stock: 73820101250001P Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the 20101250021 are classified based on electrical and mechanical parameter equivalence. All substitute candidates maintain identical specifications across current rating (125mA), voltage rating (250VAC), fuse type (cartridge glass), physical dimensions (5mm x 20mm), response time (medium blow), breaking capacity (80A), melting I²t (0.033), operating temperature range (-25°C to 70°C), and regulatory approvals (cULus). The primary distinction among substitutes lies in product status and packaging configuration. Parts designated with the "P" suffix (Series 201P) represent active production variants, while non-suffixed parts (Series 201) represent earlier production series. All substitutes maintain ROHS3 compliance and identical thermal and electrical performance characteristics.

Parameter Comparison

Engineering Selection Recommendations

For applications currently using the obsolete 20101250021, direct substitution is supported by three active alternatives: 20101250021P, 20101250001, and 20101250001P. All three maintain complete electrical and mechanical equivalence with identical current ratings, voltage specifications, physical dimensions, and thermal characteristics. Selection among these alternatives should prioritize active production status and availability. The 20101250021P represents the direct successor to the main part, maintaining the same series designation with active production status. The 20101250001 and 20101250001P variants offer equivalent performance from an earlier series designation. All substitutes carry cULus approval and ROHS3 compliance, ensuring regulatory continuity. Packaging configuration (bulk) is consistent across all alternatives.

Frequently Asked Questions (FAQ)

Q: Can 20101250021P be used as a direct replacement for 20101250021? A: Yes. The 20101250021P maintains identical electrical specifications (125mA, 250VAC), physical dimensions (5mm x 20mm), response characteristics (medium blow), and regulatory approvals (cULus). The primary difference is active production status versus obsolete status.

Q: What is the difference between Series 201 and Series 201P variants? A: Both series maintain identical electrical and mechanical parameters. The "P" designation indicates active production variants. Series 201 represents earlier production, while Series 201P represents current production. All parameters remain equivalent for substitution purposes.

Q: Are all substitute parts mechanically compatible with existing fuse holders? A: Yes. All substitute parts maintain the identical 5mm x 20mm physical dimensions and cartridge glass fuse type, ensuring mechanical compatibility with holders designed for the 20101250021.

Q: Do substitute parts maintain the same thermal performance? A: Yes. All substitutes maintain identical operating temperature range (-25°C to 70°C), melting I²t (0.033), and breaking capacity (80A) specifications.

Q: Which substitute should be selected for new designs? A: For new designs, select from active production parts: 20101250021P, 20101250001, or 20101250001P. All three maintain complete equivalence and active availability status.