RI-29AA Equivalent & Substitute Parts

Part Overview

The RI-29AA is a Glass Body Reed Switch manufactured by Comus International, configured as SPST-NO (Single Pole Single Throw - Normally Open) with a rated switching capacity of 1A at 140V AC. This component operates within the 16–25AT range and is rated for 15W power dissipation. The RI-29AA is classified as Obsolete, making identification of compatible substitute parts essential for system maintenance and new design alternatives where this component is no longer available from original manufacturing stock.

Substiute Parts

RI-29AA

Comus InternationalIn Stock: 1010RI-29AA Datasheet

Current PartRFQ

RI-29GP1520

Comus InternationalIn Stock: 889RI-29GP1520 Datasheet

SimilarRFQ

MDSR-4-12-23

Littelfuse Inc.In Stock: 4594MDSR-4-12-23 Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the RI-29AA must maintain compatibility across critical electrical and mechanical parameters that define switching functionality and physical integration:

Primary Substitution Criteria:

• Circuit Configuration: SPST-NO (identical electrical topology)
• Current - Switching: Minimum 1A capability (AC/DC or DC-only acceptable if application permits)
• Voltage - Switching: Minimum 140V AC or 200V DC capability
• Power - Rated: Minimum 15W
• Operate Range: Overlap or compatibility with 16–25AT sensitivity
• Mounting Type: Through Hole (identical PCB integration)
• Termination Style: Axial (identical lead configuration)
• Overall Length: Compatible with 1.811" (46.00mm) footprint or similar

Two substitute parts meet these criteria with varying degrees of direct equivalence based on parameter alignment and product availability status.

Parameter Comparison

Engineering Selection Recommendations

RI-29GP1520 (Preferred Primary Substitute)

The RI-29GP1520 from Comus International provides the closest direct substitution for the RI-29AA. Both components share identical switching capacity (1A AC/DC at 140V AC / 200V DC), power rating (15W), mechanical footprint (1.811" length, 0.071" body diameter), and termination configuration (Through Hole Axial). The RI-29GP1520 operates within a narrower range specification (15–20AT versus 16–25AT) but remains compatible with applications within the overlap window (15–20AT). The RI-29GP1520 is Active status and ROHS3 Compliant, ensuring ongoing availability and regulatory compliance. Operating time and release time are identical at 0.25 ms and 0.03 ms respectively, with no switching characteristic degradation. Temperature operating range matches at -55°C to 75°C.

MDSR-4-12-23 (Secondary Substitute for Reduced Current Applications)

The MDSR-4-12-23 from Littelfuse Inc. is suitable where applications can accept reduced switching current (500mA DC versus 1A AC/DC). This component shares identical DC voltage rating (200V) and mounting configuration (Through Hole Axial) but has lower power rating (10W versus 15W). The MDSR-4-12-23 operates within 12–23AT range, overlapping the RI-29AA across 16–23AT. The component is Active status and ROHS3 Compliant. Physical dimensions differ slightly: 1.590" length (versus 1.811") and 0.090" body diameter (versus 0.071"), requiring PCB layout verification. Operating time is slower at 0.6 ms (versus 0.25 ms), and AC voltage rating is not specified. This part is suitable only when current requirements do not exceed 500mA and when extended thermal operating range (-40°C to 125°C) provides design benefit.

Frequently Asked Questions (FAQ)

Q: Can RI-29GP1520 directly replace RI-29AA without design modifications?

A: RI-29GP1520 is the recommended direct replacement. Both components have identical electrical ratings (1A at 140V AC/200V DC), power dissipation (15W), physical footprint (1.811" length), and switching response (0.25 ms operate / 0.03 ms release). The narrower operate range (15–20AT versus 16–25AT) is compatible for applications within the 15–20AT overlap. No design modifications are required for existing PCB layouts or circuit designs.

Q: Under what conditions can MDSR-4-12-23 be used as a substitute?

A: MDSR-4-12-23 is suitable for applications where switching current does not exceed 500mA DC and where rated power is below 10W. The component cannot be used with AC current sources, as only DC switching current is specified. PCB layout changes may be necessary due to physical size differences (1.590" length, 0.090" body diameter). Slower switching response (0.6 ms operate) must be acceptable for the application timing requirements.

Q: What is the impact of the narrower operate range in RI-29GP1520?

A: RI-29GP1520 operates within 15–20AT versus RI-29AA at 16–25AT. For applications requiring actuation above 20AT, RI-29GP1520 will not reliably close the switch. Applications operating within the 15–20AT window remain fully compatible. Applications designed for 21–25AT magnetic field strength require alternative components or circuit redesign.

Q: Are all substitute parts RoHS compliant?

A: Yes. RI-29AA is RoHS Compliant. RI-29GP1520 and MDSR-4-12-23 are both ROHS3 Compliant, meeting current regulatory standards. All parts are REACH Unaffected and classified under ECCN EAR99.

Q: How do physical dimensions affect substitution?

A: RI-29GP1520 maintains identical dimensions to RI-29AA (1.811" length, 0.071" body diameter), ensuring PCB footprint compatibility and no layout changes. MDSR-4-12-23 has different dimensions (1.590" length, 0.090" body diameter), requiring PCB layout verification and potential mechanical redesign for mounting fixtures or spacing constraints.

Q: What inventory status should influence the substitution decision?

A: RI-29AA (990 units) is Obsolete status. RI-29GP1520 (843 units) and MDSR-4-12-23 (4501 units) are Active status with current manufacturing. For new designs or long-term production, Active status components ensure supply chain continuity. For legacy system repair with limited quantities, availability depends on distributor inventory levels.