Equivalent & Substitute Parts for Honeywell 21SM1-T Snap Action Switch

Part Overview

The Honeywell 21SM1-T is an SPDT snap action switch rated for 5A at 250V AC and 30V DC, featuring a round pin plunger actuator and chassis mount configuration with solder turret termination. This component is classified as Active product status and is RoHS Compliant with MSL 1 rating.

Substitute parts are identified for applications requiring equivalent switching functionality with compatible electrical and mechanical parameters. Substitution necessity arises from inventory availability, manufacturing discontinuation of certain models, or specific application requirements within the allowed parameter ranges.

Substiute Parts

21SM1-T

Honeywell Sensing and Productivity SolutionsIn Stock: 70221SM1-T Datasheet

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DB1C-A1AA

Hirose Electric Co LtdIn Stock: 919DB1C-A1AA Datasheet

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DC1C-A1AA

ZF ElectronicsIn Stock: 21897DC1C-A1AA Datasheet

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DC2C-A1AA

ZF ElectronicsIn Stock: 1173DC2C-A1AA Datasheet

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DC3C-A1AA

Hirose Electric Co LtdIn Stock: 1171DC3C-A1AA Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the 21SM1-T are identified based on the following critical parameters that determine functional equivalence:

Primary Compatibility Criteria:

• Circuit configuration: SPDT
• Switch function: On-Momentary
• Actuator type: Round pin plunger
• Mounting type: Chassis mount
• Operating position: 0.330" (8.4mm)
• Differential travel: 0.004" (0.1mm)
• MSL rating: 1 (Unlimited)

Allowable Parameter Variations: Substitute parts may differ in voltage ratings (AC/DC), current ratings, operating force, pretravel, overtravel, operating temperature range, mechanical life cycles, termination style, and product status, provided the core switching architecture and mechanical interface remain compatible.

The following parts meet substitution criteria:

• DB1C-A1AA (Hirose Electric Co Ltd) - Obsolete status
• DC1C-A1AA (ZF Electronics) - Active status, reduced voltage ratings
• DC2C-A1AA (ZF Electronics) - Active status, increased current rating
• DC3C-A1AA (Hirose Electric Co Ltd) - Obsolete status

Parameter Comparison

Engineering Selection Recommendations

Active Product Status Substitutes:

DC1C-A1AA and DC2C-A1AA from ZF Electronics are classified as Active products with ROHS3 compliance. These parts maintain SPDT configuration, on-momentary function, round pin plunger actuation, and chassis mount design. DC1C-A1AA operates at reduced voltage ratings (125V AC, 48V DC) with 5A AC and 1A DC current capacity. DC2C-A1AA provides increased current capacity at 10A AC with 125V AC rating. Both ZF Electronics substitutes feature solder lug termination and extended mechanical life of 1,000,000 cycles compared to the 21SM1-T specification of 80,000 cycles.

Obsolete Product Status Substitutes:

DB1C-A1AA and DC3C-A1AA are classified as Obsolete. These parts maintain mechanical and electrical interface compatibility but are no longer in active production. Selection of obsolete substitutes is appropriate only when inventory availability of active alternatives is insufficient and application requirements do not mandate ongoing product support.

Compliance Considerations:

All substitute parts maintain MSL 1 (Unlimited) rating and EAR99 ECCN classification consistent with the 21SM1-T. ZF Electronics substitutes provide ROHS3 compliance, exceeding the RoHS Compliant status of the primary part. All parts share identical HTSUS classification 8536.50.7000.

Termination Style Variation:

The 21SM1-T features solder turret termination. DC1C-A1AA and DC2C-A1AA utilize solder lug termination. This variation requires circuit board layout modification and is not a direct mechanical interchange without PCB redesign.

Frequently Asked Questions (FAQ)

Q: Can DC1C-A1AA directly replace 21SM1-T in existing circuit board designs?

A: DC1C-A1AA maintains identical operating position (0.330"/8.4mm), differential travel (0.004"/0.1mm), and chassis mount configuration. However, termination style differs: 21SM1-T uses solder turret while DC1C-A1AA uses solder lug. Direct PCB substitution requires termination pad modification. Electrical ratings differ: DC1C-A1AA is rated 125V AC and 48V DC versus 21SM1-T at 250V AC and 30V DC.

Q: What is the primary difference between DC1C-A1AA and DC2C-A1AA?

A: Both parts are manufactured by ZF Electronics with identical mechanical specifications and operating characteristics. DC2C-A1AA provides increased current capacity at 10A AC compared to DC1C-A1AA at 5A AC. Both operate at 125V AC. DC2C-A1AA features higher operating force at 340gf versus 204gf for DC1C-A1AA.

Q: Why are DB1C-A1AA and DC3C-A1AA listed as Obsolete?

A: Product status reflects manufacturer classification. Obsolete designation indicates these parts are no longer in active production. Inventory availability may vary by distributor. Selection of obsolete parts is appropriate only when active alternatives cannot meet application requirements or inventory constraints exist.

Q: Are all substitute parts RoHS compliant?

A: The 21SM1-T is RoHS Compliant. DC1C-A1AA and DC2C-A1AA are ROHS3 Compliant, which represents an enhanced compliance standard. DB1C-A1AA and DC3C-A1AA RoHS status is not specified in available documentation.

Q: What is the mechanical life difference between 21SM1-T and ZF Electronics substitutes?

A: The 21SM1-T is rated for 80,000 mechanical cycles. DC1C-A1AA and DC2C-A1AA are rated for 1,000,000 mechanical cycles, representing a 12.5-fold increase in cycle life. This difference reflects design variations and does not affect substitution compatibility for applications within the 21SM1-T cycle specification.

Q: Can 21SM1-T be used in applications requiring 10A current capacity?

A: No. The 21SM1-T is rated for 5A AC/DC maximum. Applications requiring 10A capacity must use DC2C-A1AA, which is rated for 10A AC. DC2C-A1AA maintains SPDT configuration and on-momentary function but operates at 125V AC maximum versus 21SM1-T at 250V AC.

Q: What packaging is available for substitute parts?

A: The 21SM1-T is supplied in Bulk packaging. DC1C-A1AA and DC2C-A1AA are supplied in Bulk packaging. DB1C-A1AA and DC3C-A1AA packaging information is not specified in available documentation.

Q: Are operating temperature ranges equivalent across all parts?

A: No. The 21SM1-T operates from -55°C to 125°C. DC1C-A1AA and DC2C-A1AA operate from -40°C to 120°C. Applications requiring operation below -40°C must use the 21SM1-T. The 21SM1-T provides 15°C additional upper temperature margin.