ST12KMZQ Toggle Switch SPDT Equivalent & Substitute Parts

Part Overview

The ST12KMZQ is an APEM Inc. toggle switch featuring SPDT (Single Pole Double Throw) circuitry with On-Off-On switching function, rated for 6A at 125V AC and 7A at 30V DC. This component is classified as obsolete, necessitating identification of functionally equivalent alternatives for new designs and ongoing system maintenance. The panel-mount configuration with solder lug termination and 1/4-40 bushing thread defines its mechanical interface requirements.

Substiute Parts

ST12KMZQ

APEM Inc.In Stock: 1198ST12KMZQ Datasheet

Current PartRFQ

2-1825137-0

TE Connectivity ALCOSWITCH SwitchesIn Stock: 18572-1825137-0 Datasheet

SimilarRFQ

MTA106DPC

TE Connectivity ALCOSWITCH SwitchesIn Stock: 1032MTA106DPC Datasheet

SimilarRFQ

T102SHZQE

C&KIn Stock: 1966T102SHZQE Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the ST12KMZQ is determined by the following critical parameters: circuit configuration (SPDT), switch function (On-Off-On), current and voltage ratings, mounting type (panel mount), termination style (solder lug), panel cutout dimensions, and bushing thread specification. Parts meeting all these criteria are considered direct substitutes. Parts with deviations in circuit configuration, switch function, or mechanical interface parameters are classified as partial substitutes requiring design review.

The substitute parts identified from the provided list demonstrate varying degrees of compatibility:

• 2-1825137-0 (TE Connectivity ALCOSWITCH): Matches SPDT circuit and On-Off-On function with compatible mechanical interface (1/4-40 bushing, 6.35mm cutout, solder lug termination). Current rating reduced to 5A AC/DC; voltage rating 120V AC/28V DC.

• MTA106DPC (TE Connectivity ALCOSWITCH): Matches SPDT circuit with compatible mechanical interface (1/4-40 bushing, solder lug termination). Switch function differs (On-On vs. On-Off-On); termination style differs (PC Pin vs. Solder Lug); current rating 6A AC/4A DC; voltage rating 125V AC/28V DC.

• T102SHZQE (C&K): Circuit configuration differs (SPST vs. SPDT); switch function differs (On-Off vs. On-Off-On); current rating significantly reduced (2A AC/DC); mechanical interface differs (10-48 bushing thread, 4.95mm cutout, solder lug termination).

Parameter Comparison

Engineering Selection Recommendations

2-1825137-0 (TE Connectivity ALCOSWITCH Gemini A Series) is the primary substitute candidate. It maintains SPDT circuit configuration, On-Off-On switching function, compatible mechanical interface (1/4-40 bushing, 6.35mm panel cutout, solder lug termination), and identical operating temperature range. Current rating is reduced to 5A AC/DC with 120V AC/28V DC voltage rating. Electrical life is reduced to 6,000 cycles compared to 40,000 cycles in the original. This part is active and ROHS3 compliant.

MTA106DPC (TE Connectivity ALCOSWITCH MTA Green Series) is a secondary substitute option. It maintains SPDT circuit configuration, compatible mechanical interface (1/4-40 bushing, solder lug termination), and current rating of 6A AC/4A DC at 125V AC/28V DC. However, the switch function differs (On-On vs. On-Off-On), and termination style is PC Pin rather than solder lug. Operating temperature range is narrower (-20°C ~ 80°C). Electrical life is superior at 80,000 cycles. This part is active and ROHS3 compliant.

T102SHZQE (C&K T Series) is not recommended as a direct substitute. Circuit configuration is SPST (not SPDT), switch function is On-Off (not On-Off-On), current rating is significantly reduced to 2A AC/DC, and mechanical interface differs (10-48 bushing thread, 4.95mm panel cutout). This part is active and ROHS3 compliant but does not meet the functional requirements of the ST12KMZQ.

Frequently Asked Questions (FAQ)

Q: Can 2-1825137-0 directly replace ST12KMZQ in all applications?

A: 2-1825137-0 is compatible for applications where the reduced current rating (5A AC/DC vs. 6A/7A) and reduced electrical life (6,000 vs. 40,000 cycles) are acceptable. The SPDT circuit, On-Off-On function, and mechanical interface are identical. Verify application current requirements before substitution.

Q: What is the difference between SPDT and SPST circuit configurations?

A: SPDT (Single Pole Double Throw) provides three terminals with two switching positions, allowing connection to two separate circuits. SPST (Single Pole Single Throw) provides two terminals with one switching position. The ST12KMZQ requires SPDT functionality; SPST parts cannot replicate this behavior.

Q: Why does MTA106DPC have different termination style?

A: MTA106DPC uses PC Pin termination instead of solder lug. This requires different PCB footprint and assembly process. Panel cutout dimensions are also slightly larger (6.40mm vs. 6.35mm). Mechanical redesign may be necessary for direct substitution.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All identified substitute parts (2-1825137-0, MTA106DPC, T102SHZQE) are ROHS3 compliant, matching the compliance status of the ST12KMZQ.

Q: What is the impact of reduced electrical life in 2-1825137-0?

A: The 2-1825137-0 has 6,000 electrical life cycles compared to 40,000 in the ST12KMZQ. For applications with frequent switching, this represents a 6.67x reduction in rated cycle life. Evaluate application duty cycle to determine if this reduction is acceptable.

Q: Can T102SHZQE be used if circuit redesign is possible?

A: T102SHZQE cannot replicate SPDT On-Off-On functionality due to its SPST On-Off configuration. Circuit redesign would be required to accommodate this functional limitation, making it unsuitable as a substitute for the ST12KMZQ.