MJS 1.25 Equivalent & Substitute Parts

Part Overview

The MJS 1.25 is a 1.25 A, 250 V AC/DC slow-blow glass cartridge fuse in 2AG package format (5mm x 15mm axial). Manufactured by Bel Fuse Inc., this component is classified as obsolete. Due to its obsolete status, locating direct inventory may present supply chain challenges. Identifying active equivalent parts ensures design continuity and maintains circuit protection specifications without redesign requirements.

Substiute Parts

MJS 1.25

Bel Fuse Inc.In Stock: 1151MJS 1.25 Datasheet

Current PartRFQ

MJS 1.25-R

Bel Fuse Inc.In Stock: 1011MJS 1.25-R Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the MJS 1.25 is determined by strict equivalence across the following parameters:

• Current Rating: 1.25 A (exact match required)
• Voltage Rating: 250 V AC (exact match required)
• Fuse Type: Cartridge, Glass (exact match required)
• Package / Case: 2AG, 5mm x 15mm (Axial) (exact match required)
• Response Time: Slow Blow (exact match required)
• Breaking Capacity: 200 A (exact match required)
• Melting I²t: 9 (exact match required)

The MJS 1.25-R qualifies as a direct substitute because it maintains identical electrical and mechanical specifications across all critical parameters. The primary distinction is product status: MJS 1.25-R is active and readily available, whereas MJS 1.25 is obsolete.

Parameter Comparison

Engineering Selection Recommendations

The MJS 1.25-R is the direct substitute for the obsolete MJS 1.25. Both parts maintain identical electrical performance and mechanical compatibility. The MJS 1.25-R offers the following advantages:

• Active product status ensures ongoing availability and supply chain reliability
• ROHS3 compliance aligns with current environmental regulations
• Improved DC cold resistance (0.127 Ohms vs. 0.195 Ohms) provides marginal performance enhancement
• Expanded approval certifications (cULus addition) broaden regulatory acceptance

No circuit redesign or footprint modification is required for substitution. Direct pin-for-pin and form-factor replacement is applicable.

Frequently Asked Questions (FAQ)

Q: Can MJS 1.25-R be used as a direct replacement for MJS 1.25?

A: Yes. Both parts are electrically and mechanically identical across all critical parameters: 1.25 A current rating, 250 V AC voltage rating, slow-blow response, 2AG package format, and 200 A breaking capacity. No circuit modifications are necessary.

Q: What is the primary reason to substitute MJS 1.25 with MJS 1.25-R?

A: The MJS 1.25 is obsolete, creating supply availability constraints. The MJS 1.25-R is an active product from the same manufacturer with identical specifications, ensuring reliable procurement.

Q: Are there differences in compliance certifications between these parts?

A: Both parts carry CE, CSA, and PSE certifications. The MJS 1.25-R includes cULus certification in addition to UL. The MJS 1.25-R is ROHS3 compliant, while the MJS 1.25 is RoHS non-compliant.

Q: Does the difference in DC cold resistance affect circuit performance?

A: DC cold resistance values (0.195 Ohms vs. 0.127 Ohms) represent minimal variation and do not impact circuit protection function or safety performance in standard applications.

Q: Are packaging options different between these parts?

A: The MJS 1.25 is available in standard packaging. The MJS 1.25-R is supplied in bulk packaging. Both maintain identical 2AG form factor and axial through-hole mounting configuration.