RI-25A Equivalent & Substitute Parts

Part Overview

The RI-25A is a glass body reed switch manufactured by Comus International, designed for SPST-NO (Single Pole Single Throw, Normally Open) switching applications. This component operates at 140V AC / 200V DC with a 1A (AC/DC) switching capacity and 15W rated power. The RI-25A is classified as obsolete, necessitating identification of compatible substitute components for ongoing design requirements and maintenance applications where equivalent electrical and mechanical characteristics are required.

Substiute Parts

RI-25A

Comus InternationalIn Stock: 740RI-25A Datasheet

Current PartRFQ

MLRR-3-22-28

LittelfuseIn Stock: 1657MLRR-3-22-28 Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the RI-25A is based on the following key electrical and mechanical parameters that determine compatibility:

Electrical Compatibility Criteria:

• Circuit configuration: SPST-NO
• Voltage switching capability: 140V AC / 200V DC minimum
• Current switching capacity: 1A minimum (AC/DC)
• Rated power: 15W minimum
• Operating temperature range: Must accommodate -55°C ~ 125°C or compatible subset

Mechanical Compatibility Criteria:

• Mounting type: Through Hole
• Termination style: Axial
• Package type: Glass body reed switch

The MLRR-3-22-28 from Littelfuse meets these substitution criteria with equivalent or superior electrical ratings and identical mechanical mounting requirements.

Parameter Comparison

Engineering Selection Recommendations

The MLRR-3-22-28 is suitable as a substitute for the RI-25A based on the following factors:

Compliance and Availability: The MLRR-3-22-28 carries ROHS3 certification, exceeding the RoHS compliance of the original RI-25A. As an active product with 1582 units in inventory, the MLRR-3-22-28 provides reliable procurement compared to the obsolete RI-25A.

Electrical Equivalence: Both components share identical AC and DC voltage switching ratings (140V AC / 200V DC). The MLRR-3-22-28 provides superior rated power (20W versus 15W), accommodating the original design envelope with additional margin.

DC Current Equivalence: Both components support 1A DC switching current, matching the original specification for DC applications.

AC Current Consideration: The MLRR-3-22-28 operates at 700mA AC switching current, which is lower than the RI-25A's 1A AC rating. Selection for AC applications requires confirmation that design requirements do not exceed 700mA.

Mechanical Compatibility: Both components employ through-hole axial termination, ensuring mechanical compatibility with existing PCB designs without modification.

Operating Temperature: The MLRR-3-22-28 operates from -40°C to 125°C, narrowing the lower temperature range from the RI-25A's -55°C specification. Selection requires confirmation that the minimum operating temperature requirement does not fall below -40°C.

Frequently Asked Questions (FAQ)

Q: Can the MLRR-3-22-28 directly replace the RI-25A in all applications?

A: Substitution is valid for DC switching applications and AC applications not exceeding 700mA. For AC applications requiring 1A switching current, the MLRR-3-22-28 current rating is insufficient. Confirm operating temperature requirements do not necessitate operation below -40°C.

Q: What are the key differences between these components?

A: The primary differences are AC current switching capacity (700mA vs. 1A), operating temperature minimum (-40°C vs. -55°C), and product status (active vs. obsolete). Voltage ratings, DC current capacity, and mechanical mounting are equivalent.

Q: Are there mechanical package differences?

A: Both components use through-hole axial termination with glass body reed construction. Physical dimensions differ slightly (MLRR-3-22-28 is 2.230" vs. RI-25A at 1.811" overall length), but both mount identically to through-hole PCB patterns.

Q: What compliance certifications apply to the MLRR-3-22-28?

A: The MLRR-3-22-28 carries ROHS3 compliance, REACH unaffected status, and EAR99 export classification, consistent with the original RI-25A specification.

Q: Why is the RI-25A obsolete?

A: The RI-25A has been discontinued by Comus International. The MLRR-3-22-28 from Littelfuse provides equivalent functionality for active design and maintenance requirements.

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