MS 1TR Equivalent & Substitute Parts

Part Overview

The MS 1TR is a board mount axial fuse manufactured by Bel Fuse Inc., rated for 1 A at 125 V AC/DC with slow blow response characteristics. This component is classified as obsolete, making equivalent substitutes necessary for ongoing production and maintenance applications. The MS 1TR serves as a protective device in electronic circuits requiring reliable overcurrent protection with slow blow response time and through-hole axial mounting.

Substiute Parts

MS 1TR

Bel Fuse Inc.In Stock: 792MS 1TR Datasheet

Current PartRFQ

0473001.MRT1L

Littelfuse Inc.In Stock: 32700473001.MRT1L Datasheet

DirectRFQ

0473001.YRT1L

Littelfuse Inc.In Stock: 281210473001.YRT1L Datasheet

DirectRFQ

0471001.NRT1L

Littelfuse Inc.In Stock: 94060471001.NRT1L Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution for the MS 1TR is determined by strict equivalence across the following electrical and mechanical parameters: current rating (1 A), AC voltage rating (125 V), DC voltage rating (125 V), response time (slow blow), mounting type (through hole), and package type (axial). All substitute parts must maintain these core specifications to ensure functional compatibility within the original circuit design.

The substitute parts are grouped into two categories:

Direct Substitutes (PICO® II 473 Series): Parts 0473001.MRT1L and 0473001.YRT1L meet all electrical specifications and are manufactured by Littelfuse Inc. with active product status. These parts are functionally equivalent and interchangeable with the MS 1TR.

Similar Substitute (PICO® II 471 Series): Part 0471001.NRT1L shares all electrical ratings and response characteristics but differs in physical dimensions (0.110" diameter versus 0.125" for MS 1TR and 0.135" for PICO® II 473 series). This dimensional variation may affect board layout compatibility.

Parameter Comparison

Engineering Selection Recommendations

For Direct Replacement: Parts 0473001.MRT1L and 0473001.YRT1L are the primary substitutes for the obsolete MS 1TR. Both parts maintain electrical equivalence across all critical parameters: 1 A current rating, 125 V AC/DC voltage ratings, slow blow response, and through-hole axial mounting. Both are manufactured by Littelfuse Inc. with active product status and ROHS3 compliance. The PICO® II 473 series offers superior availability (3,210 and 28,100 units in stock respectively) compared to the original MS 1TR (723 units). Dimensional differences (0.135" diameter versus 0.125" for MS 1TR) are minor and typically accommodate standard PCB hole spacing.

For Space-Constrained Applications: Part 0471001.NRT1L (PICO® II 471 series) provides an alternative with reduced physical diameter (0.110") while maintaining all electrical specifications. This option is suitable only when board layout constraints require the smaller form factor. The lower DC cold resistance (0.085 Ohms) and melting I²t (0.722) differ from the MS 1TR but remain within acceptable parameters for 1 A slow blow protection.

Compliance Considerations: All substitute parts carry CSA and UR certifications. The MS 1TR includes CE and cURus certifications; substitute parts include PSE certification instead. Verify that your application requirements align with the certification profile of the selected substitute.

Frequently Asked Questions (FAQ)

Q: Can 0473001.MRT1L and 0473001.YRT1L be used interchangeably with MS 1TR?

A: Yes. Both parts are electrically equivalent to the MS 1TR, sharing identical current rating (1 A), voltage ratings (125 V AC/DC), response time (slow blow), and mounting configuration (through hole axial). The primary difference is physical diameter (0.135" versus 0.125"), which does not affect electrical function in standard PCB applications.

Q: What is the difference between 0473001.MRT1L and 0473001.YRT1L?

A: Both parts are from the PICO® II 473 series with identical electrical and mechanical specifications. The difference is packaging: 0473001.MRT1L is supplied in cut tape, while 0473001.YRT1L is also supplied in cut tape. Inventory availability differs (3,210 units versus 28,100 units).

Q: When should 0471001.NRT1L be selected instead of the PICO® II 473 series?

A: Part 0471001.NRT1L is selected only when board layout constraints require a smaller diameter fuse (0.110" versus 0.135"). All electrical parameters remain equivalent. Verify PCB hole spacing compatibility before selection.

Q: Are there compliance differences between MS 1TR and the substitute parts?

A: Yes. MS 1TR carries CE, CSA, and cURus certifications. Littelfuse substitutes carry CSA, PSE, and UR certifications. Verify that your application requirements align with the certification profile of the selected substitute, particularly if CE marking is mandatory.

Q: What is the significance of the melting I²t difference?

A: Melting I²t indicates the thermal energy required to melt the fuse element. MS 1TR has I²t of 0.81, while PICO® II 473 parts have I²t of 2.01. Both values are within the slow blow classification for 1 A fuses. The difference reflects manufacturing design variations between manufacturers but does not affect functional compatibility for standard 1 A protection applications.

Q: Can MS 1TR be used in new designs, or must substitutes be selected?

A: MS 1TR is classified as obsolete and should not be selected for new designs. Use active substitute parts 0473001.MRT1L or 0473001.YRT1L for all new applications requiring 1 A slow blow axial fuse protection.