2JS 1.25-R Equivalent & Substitute Parts

Part Overview

The 2JS 1.25-R is a 1.25 A slow blow glass cartridge fuse manufactured by Bel Fuse Inc., rated for 350 V AC and 140 V DC operation. This fuse is designed for applications requiring reliable overcurrent protection in the 2AG form factor (5mm x 15mm). The part maintains active product status with full compliance to international safety standards including CE, CSA, cURus, and PSE certifications. Substitute parts are identified to provide alternative sourcing options when the primary part is unavailable or when inventory requirements necessitate qualified alternatives.

Substiute Parts

2JS 1.25-R

Bel Fuse Inc.In Stock: 13192JS 1.25-R Datasheet

Current PartRFQ

02291.25MXP

Littelfuse Inc.In Stock: 180802291.25MXP Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the 2JS 1.25-R is determined by the following critical parameters:

• Current Rating: Must be 1.25 A to ensure identical overcurrent protection characteristics
• Fuse Type & Package: Must be cartridge glass fuse in 2AG form factor (5mm x 15mm) for mechanical and electrical holder compatibility
• Response Time: Must be slow blow to match application-specific inrush current tolerance
• Operating Temperature Range: Must support -55°C ~ 125°C minimum to ensure performance across specified environmental conditions
• RoHS Compliance: Must maintain ROHS3 compliance for regulatory alignment

The substitute part 02291.25MXP (Littelfuse Inc., Series 229) meets these core substitution criteria. However, voltage ratings differ: the substitute is rated for 250 V AC and 125 V DC compared to the main part's 350 V AC and 140 V DC ratings. This voltage differential must be evaluated against specific application requirements.

Parameter Comparison

Engineering Selection Recommendations

Both the 2JS 1.25-R and 02291.25MXP maintain active product status and full RoHS3 compliance. The 2JS 1.25-R carries CE, CSA, cURus, and PSE certifications. The 02291.25MXP carries CE, CSA, PSE, and UL certifications. Selection between these parts must be based on the specific voltage requirements of the application circuit. The 2JS 1.25-R is suitable for circuits operating at or below 350 V AC / 140 V DC. The 02291.25MXP is suitable for circuits operating at or below 250 V AC / 125 V DC. Both parts share identical current ratings, response characteristics, and mechanical form factors, ensuring functional equivalence within their respective voltage operating ranges.

Frequently Asked Questions (FAQ)

Q: Can the 02291.25MXP substitute for the 2JS 1.25-R in all applications?

A: Substitution is valid only when the application circuit operates at or below 250 V AC and 125 V DC. If the circuit requires the full 350 V AC / 140 V DC rating of the 2JS 1.25-R, the 02291.25MXP is not suitable.

Q: Are the physical dimensions compatible between these two fuses?

A: Both fuses use the 2AG form factor (5mm x 15mm). Minor dimensional variations exist (2JS 1.25-R: 0.201" Dia x 0.543" L; 02291.25MXP: 0.177" Dia x 0.570" L), but both fit standard 2AG fuse holders.

Q: What is the significance of the melting I²t and DC cold resistance differences?

A: The melting I²t values (9.3 vs. 9.8) and DC cold resistance values (0.127 vs. 0.146 Ohms) are within acceptable tolerance for slow blow 1.25 A fuses. These minor differences do not affect substitution eligibility for equivalent overcurrent protection.

Q: Do both parts support the same operating temperature range?

A: Yes, both the 2JS 1.25-R and 02291.25MXP operate across -55°C ~ 125°C, ensuring thermal compatibility across standard industrial and commercial environments.

Q: Which certifications should I prioritize when selecting between these parts?

A: Certification selection depends on the target market and regulatory requirements. The 2JS 1.25-R includes cURus certification; the 02291.25MXP includes UL certification. Both include CE, CSA, and PSE certifications. Verify that the selected part meets all applicable regional and industry-specific certification requirements for your application.