RI-23A Glass Body Reed Switch SPST-NO Equivalent & Substitute Parts

Part Overview

The RI-23A is a glass body reed switch manufactured by Comus International, classified as SPST-NO (Single Pole Single Throw - Normally Open) with a rated switching capacity of 500mA at 140V AC and 200V DC. This component is rated for 10W power dissipation with an operate range of 18–32AT and is mounted through-hole with axial termination.

The RI-23A is currently listed as obsolete. Identifying equivalent and substitute parts is necessary to maintain design continuity, ensure supply chain availability, and support ongoing production or repair requirements. Substitute parts must maintain functional compatibility within the electrical and mechanical parameters specified for this product category.

Key Parameters

Parameter	RI-23A Value
Manufacturer	Comus International
Series	RI-23
Circuit Configuration	SPST-NO
Type	Glass Body Reed
Operate Range	18–32AT
Current - Switching (AC/DC)	500mA
Voltage - Switching AC	140V
Voltage - Switching DC	200V
Power - Rated	10W
Mounting Type	Through Hole
Termination Style	Axial
Operating Temperature Range	−55°C to 125°C
RoHS Status	RoHS Compliant
Product Status	Obsolete

Substitute Part Grouping Explanation

Substitute parts for the RI-23A are grouped based on the following critical parameters that determine functional compatibility:

Primary Substitution Criteria:

Circuit configuration: SPST-NO (maintained across all substitutes)
Switching current capacity: 500mA minimum (AC/DC)
Switching voltage: 140V AC minimum; 200V DC minimum
Power rating: 10W minimum
Mounting type: Through Hole
Termination style: Axial
Operating temperature range: Must encompass or exceed −55°C to 125°C
RoHS compliance status

Operate Range Consideration: The RI-23A operates within 18–32AT. Substitute parts are grouped by their operate range specifications. Parts with overlapping or encompassing operate ranges are considered functionally equivalent for applications where the magnetic field strength falls within the substitute's activation threshold.

Grouping Logic:

Group 1 (Comus International RI-23 Series): Direct manufacturer line with identical electrical ratings and similar operate ranges
Group 2 (Littelfuse MACD-14 Series): 140V AC rated switches with 10–25AT operate ranges; lower current carry capacity (1A DC vs. 2.5A DC)
Group 3 (Littelfuse MDSR-4 Series): Higher operate range (27–33AT); reduced current carry capacity and narrower temperature range
Group 4 (Littelfuse MARR-5 Series): Higher voltage rating (265V AC / 1000V DC); broader operate ranges; extended temperature range (−75°C to 125°C)

Parameter Comparison

Part Number	Manufacturer	Series	Operate Range (AT)	Current - Switching	Voltage AC	Voltage DC	Power (W)	Operate Time (ms)	Release Time (ms)	Length (mm)	Body Dia × L (mm)	Temp Range (°C)	Current Carry DC	Product Status	RoHS
RI-23A	Comus International	RI-23	18–32	500mA (AC/DC)	140V	200V	10	0.25	0.03	46.00	2.54 × 14.50	−55 to 125	2.5A	Obsolete	RoHS Compliant
RI-23GP2025	Comus International	RI-23GP	20–25	500mA (AC/DC)	140V	200V	10	0.25	0.03	46.00	2.54 × 14.50	−55 to 125	2.5A	Active	ROHS3 Compliant
MDSR-4-27-33	Littelfuse Inc.	MDSR-4	27–33	500mA (DC)	—	200V	10	0.6	0.2	40.39	2.28 × 15.24	−40 to 125	1.2A	Active	ROHS3 Compliant
MACD-14-10-15	Littelfuse Inc.	MACD-14	10–15	350mA (AC), 500mA (DC)	140V	200V	10	0.6	0.2	44.30	2.28 × 14.00	−40 to 125	1A	Active	ROHS3 Compliant
MACD-14-15-20	Littelfuse Inc.	MACD-14	15–20	350mA (AC), 500mA (DC)	140V	200V	10	0.6	0.2	44.30	2.28 × 14.00	−40 to 125	1A	Active	ROHS3 Compliant
MACD-14-20-25	Littelfuse Inc.	MACD-14	20–25	350mA (AC), 500mA (DC)	140V	200V	10	0.6	0.2	44.30	2.28 × 14.00	−40 to 125	1A	Active	ROHS3 Compliant
MARR-5-12-23	Littelfuse Inc.	MARR-5	12–23	350mA (AC), 500mA (DC)	265V	1000V	10	0.75	0.3	56.77	2.66 × 19.69	−75 to 125	1.3A	Active	ROHS3 Compliant
MARR-5-12-28	Littelfuse Inc.	MARR-5	12–28	350mA (AC), 500mA (DC)	265V	1000V	10	0.75	0.3	56.77	2.66 × 19.69	−75 to 125	1.3A	Active	ROHS3 Compliant
MARR-5-12-38	Littelfuse Inc.	MARR-5	12–38	350mA (AC), 500mA (DC)	265V	1000V	10	0.75	0.3	56.77	2.66 × 19.69	−75 to 125	1.3A	Active	ROHS3 Compliant
MARR-5-17-38	Littelfuse Inc.	MARR-5	17–38	350mA (AC), 500mA (DC)	265V	1000V	10	0.75	0.3	56.77	2.66 × 19.69	−75 to 125	1.3A	Active	ROHS3 Compliant
MARR-5-27-38	Littelfuse Inc.	MARR-5	27–38	350mA (AC), 500mA (DC)	265V	1000V	10	0.75	0.3	56.77	2.66 × 19.69	−75 to 125	1.3A	Active	ROHS3 Compliant

Engineering Selection Recommendations

Primary Recommendation: RI-23GP2025

The RI-23GP2025 is the preferred substitute for the obsolete RI-23A. This part is manufactured by Comus International within the same RI-23 product family and maintains identical electrical specifications: 500mA switching current (AC/DC), 140V AC / 200V DC switching voltage, and 10W power rating. The operate range of 20–25AT falls within the RI-23A's 18–32AT specification, ensuring functional compatibility for applications where the magnetic field strength is within this window. The RI-23GP2025 is currently in active production status with ROHS3 compliance certification, providing long-term supply assurance and regulatory alignment.

Secondary Recommendations by Application Context:

For 140V AC / 200V DC Applications with Operate Range 15–20AT: MACD-14-15-20 is suitable when the application's magnetic activation threshold falls within 15–20AT. This Littelfuse part maintains 140V AC / 200V DC voltage ratings and 10W power dissipation. Note that AC switching current is reduced to 350mA; DC switching current remains at 500mA. Current carry capacity is 1A DC (versus 2.5A for RI-23A). This part is active and ROHS3 compliant.

For 140V AC / 200V DC Applications with Operate Range 20–25AT: MACD-14-20-25 provides an alternative within the 20–25AT operate range with identical voltage and power specifications to MACD-14-15-20. This part is active and ROHS3 compliant.

For Higher Voltage Applications (265V AC / 1000V DC): The MARR-5 series (MARR-5-12-23, MARR-5-12-28, MARR-5-12-38, MARR-5-17-38, MARR-5-27-38) is suitable for applications requiring higher switching voltages. These parts maintain 10W power rating and 500mA DC switching current. Operating temperature range extends to −75°C, providing enhanced low-temperature performance. All MARR-5 variants are active and ROHS3 compliant. Selection within this series depends on the required operate range threshold.

For DC-Only Applications with Higher Operate Range (27–33AT): MDSR-4-27-33 is applicable when the application operates exclusively in DC mode and requires a 27–33AT activation threshold. This part maintains 500mA DC switching current and 200V DC voltage rating. Note that operating temperature range is limited to −40°C to 125°C (versus −55°C for RI-23A) and current carry capacity is reduced to 1.2A DC. This part is active and ROHS3 compliant.

Compliance and Supply Considerations: All recommended substitutes carry ROHS3 compliance certification, meeting current regulatory requirements. All substitute parts listed are in active production status, ensuring availability and long-term supply continuity. The RI-23A's original RoHS Compliant status is superseded by ROHS3 compliance in all active alternatives.

Frequently Asked Questions (FAQ)

Q1: Can RI-23GP2025 directly replace RI-23A in all applications?

A: RI-23GP2025 is functionally compatible with RI-23A for applications where the magnetic activation field strength falls within the 20–25AT operate range. The RI-23A's broader 18–32AT range means applications requiring activation below 20AT or above 25AT may not function correctly with RI-23GP2025. Verify the application's magnetic field strength specification before substitution.

Q2: What is the difference between AC and DC switching current ratings in the MACD-14 series?

A: The MACD-14 series specifies 350mA AC switching current and 500mA DC switching current. This indicates the maximum current the switch can safely interrupt differs by application type. For AC applications, the MACD-14 series is rated at 350mA; for DC applications, 500mA. The RI-23A maintains 500mA for both AC and DC, providing higher AC switching capacity.

Q3: Why do MARR-5 series parts have higher voltage ratings than RI-23A?

A: The MARR-5 series is designed for higher-voltage applications, with 265V AC and 1000V DC switching capability. These parts use larger glass bodies (2.66mm diameter × 19.69mm length versus 2.54mm × 14.50mm for RI-23A) to accommodate higher dielectric stress. MARR-5 parts are suitable for applications requiring voltage ratings exceeding RI-23A's 140V AC / 200V DC specification.

Q4: What does "Operate Range" (AT) mean, and how does it affect substitution?

A: Operate Range, measured in Ampere-Turns (AT), specifies the magnetic field strength required to activate the reed switch. The RI-23A operates within 18–32AT. A substitute part must have an operate range that encompasses the application's magnetic field strength. For example, if an application generates a 22AT magnetic field, both RI-23A (18–32AT) and RI-23GP2025 (20–25AT) will activate, but MDSR-4-27-33 (27–33AT) will not.

Q5: Can MDSR-4-27-33 be used in place of RI-23A?

A: MDSR-4-27-33 is not a direct substitute for RI-23A due to operate range mismatch. MDSR-4-27-33 requires 27–33AT activation, while RI-23A activates at 18–32AT. Additionally, MDSR-4-27-33 is rated for DC switching only (no AC rating), has reduced current carry capacity (1.2A versus 2.5A), and a narrower operating temperature range (−40°C to 125°C versus −55°C to 125°C). Use MDSR-4-27-33 only in applications specifically requiring 27–33AT activation in DC-only circuits.

Q6: Are all substitute parts RoHS compliant?

A: Yes. All substitute parts listed carry ROHS3 compliance certification. The original RI-23A is RoHS Compliant; all active alternatives meet the more recent ROHS3 standard, ensuring regulatory alignment for new designs and production.

Q7: What is the significance of "Product Status: Active" versus "Obsolete"?

A: Product Status indicates manufacturing availability. The RI-23A is obsolete, meaning Comus International no longer manufactures this part. Active parts (RI-23GP2025, MACD-14 series, MDSR-4-27-33, MARR-5 series) are currently in production, ensuring supply chain availability and long-term support. For new designs or ongoing production, active parts are strongly preferred.

Q8: How do operate time and release time affect switch performance?

A: Operate Time is the delay between magnetic field application and switch closure; Release Time is the delay between field removal and switch opening. RI-23A has 0.25ms operate time and 0.03ms release time. MACD-14 and MDSR-4 series have slower response (0.6ms operate, 0.2ms release), while MARR-5 series is slowest (0.75ms operate, 0.3ms release). For time-critical applications, verify that substitute response times are acceptable.

Q9: What does "Current - Carry" mean, and why is it lower in some substitutes?

A: Current - Carry (or continuous current rating) is the maximum DC current the switch contacts can safely carry without degradation. RI-23A carries 2.5A DC; MACD-14 series carries 1A DC; MDSR-4-27-33 carries 1.2A DC; MARR-5 series carries 1.3A DC. If the application requires continuous current above the substitute's rating, contact degradation and premature failure may occur. Verify the application's continuous current requirement before substitution.

Q10: Can I use a MARR-5 part in a 140V AC application?

A: MARR-5 parts are rated for 265V AC, which exceeds 140V AC requirements. However, MARR-5 parts are physically larger (56.77mm length versus 46.00mm for RI-23A) and have different operate ranges. Substitution is possible only if the application's magnetic field strength falls within the selected MARR-5 variant's operate range and physical space permits the larger package. Verify both electrical and mechanical compatibility before substitution.

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