Grayhill 78B12S DIP Switch - Equivalent & Substitute Parts

Part Overview

The Grayhill 78B12S is a 12-position slide actuator DIP switch rated for 150mA at 30VDC, designed for through-hole mounting in electronic control and configuration applications. This component features SPST (Single Pole Single Throw) circuit configuration with gold-plated copper alloy contacts and thermoplastic housing.

The 78B12S carries an Obsolete product status. Identifying equivalent and substitute parts is necessary to maintain design continuity, ensure supply chain availability, and support legacy system maintenance and production requirements.

Key Parameters

Parameter	Value
Circuit Configuration	SPST
Number of Positions	12
Current Rating	150mA
Voltage Rating	30VDC
Actuator Type	Slide (Standard)
Mounting Type	Through Hole
Pitch	0.100" (2.54mm)
Contact Finish	Gold
Operating Temperature Range	-40°C to 85°C
Mechanical Life	2,000 Cycles
Electrical Life	2,000 Cycles

Substitute Part Grouping Explanation

Substitute parts for the 78B12S are evaluated based on the following critical parameters that determine functional compatibility:

Primary Compatibility Criteria:

Circuit type (SPST)
Number of positions (12)
Mounting method (Through Hole)
Pitch spacing (0.100" / 2.54mm)
Actuator style (Slide Standard)
Contact finish (Gold)

Secondary Compatibility Criteria:

Current rating (must equal or exceed 150mA)
Voltage rating (must equal or exceed 30VDC)
Operating temperature range (must encompass -40°C to 85°C minimum)
Termination style (PC Pin)

Two substitute parts are identified:

78B12ST (Grayhill Inc.) - Direct equivalent with identical electrical and mechanical specifications. Differs only in product status (Active vs. Obsolete) and RoHS compliance level.

206-12ST (CTS Electrocomponents) - Functional substitute with reduced electrical ratings (50mA at 24VDC vs. 150mA at 30VDC). Maintains all mechanical and interface parameters. Suitable only for applications operating within the lower electrical envelope.

Parameter Comparison

Parameter	78B12S (Main Part)	78B12ST (Substitute)	206-12ST (Substitute)
Manufacturer	Grayhill Inc.	Grayhill Inc.	CTS Electrocomponents
Circuit	SPST	SPST	SPST
Number of Positions	12	12	12
Current Rating	150mA	150mA	50mA
Voltage Rating	30VDC	30VDC	24VDC
Actuator Type	Slide (Standard)	Slide (Standard)	Slide (Standard)
Mounting Type	Through Hole	Through Hole	Through Hole
Pitch	0.100" (2.54mm)	0.100" (2.54mm)	0.100" (2.54mm)
Contact Finish	Gold	Gold	Gold
Height Above Board	0.315" (8.00mm)	0.315" (8.00mm)	0.334" (8.48mm)
Operating Temperature	-40°C to 85°C	-40°C to 85°C	-55°C to 85°C
Mechanical Life	2,000 Cycles	2,000 Cycles	Not Specified
Electrical Life	2,000 Cycles	2,000 Cycles	10,000 Cycles
Product Status	Obsolete	Active	Active
RoHS Status	Non-compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

For Direct Replacement (Identical Electrical Performance):

The 78B12ST is the primary substitute for the obsolete 78B12S. Both parts share identical electrical ratings (150mA at 30VDC), mechanical specifications, and operating temperature range. The 78B12ST is currently in Active product status with 5,605 units in stock. The 78B12ST achieves ROHS3 compliance, whereas the 78B12S is RoHS non-compliant. Selection of 78B12ST eliminates obsolescence risk and provides regulatory compliance for new designs or production runs.

For Reduced-Load Applications:

The 206-12ST from CTS Electrocomponents functions as a substitute only in applications where the circuit operates at or below 50mA and 24VDC. This part offers extended electrical life (10,000 cycles vs. 2,000 cycles) and expanded low-temperature operating range (-55°C vs. -40°C). The 206-12ST is suitable for low-power configuration and control circuits. Height above board is 0.334" (8.48mm) compared to 0.315" (8.00mm) for the Grayhill parts; verify PCB clearance in space-constrained layouts.

Compliance Considerations:

Both substitute parts achieve ROHS3 compliance and REACH Unaffected status. The 78B12S is RoHS non-compliant; designs requiring regulatory compliance must transition to 78B12ST or 206-12ST.

Frequently Asked Questions (FAQ)

Q: Can the 206-12ST replace the 78B12S in all applications?

A: No. The 206-12ST is rated for 50mA at 24VDC, while the 78B12S is rated for 150mA at 30VDC. The 206-12ST functions only in circuits operating within its lower electrical envelope. Verify actual circuit current and voltage requirements before substitution.

Q: What is the primary difference between 78B12S and 78B12ST?

A: The 78B12ST is the active production equivalent of the obsolete 78B12S. Electrical and mechanical specifications are identical. The 78B12ST achieves ROHS3 compliance; the 78B12S does not. The 78B12ST is recommended for all new designs and ongoing production.

Q: Are there packaging differences between substitute parts?

A: The 78B12S packaging is listed as "-" (unspecified). Both 78B12ST and 206-12ST are supplied in Tube packaging. Verify packaging requirements for your assembly process.

Q: Does the 206-12ST fit the same PCB footprint?

A: Yes, the 206-12ST maintains the same 0.100" (2.54mm) pitch and through-hole termination. However, the height above board is 0.334" (8.48mm) versus 0.315" (8.00mm) for Grayhill parts. Verify clearance in applications with height constraints.

Q: Which substitute part should be selected for new designs?

A: The 78B12ST is the recommended choice for new designs requiring 150mA at 30VDC performance. It provides direct electrical equivalence, active product status, and ROHS3 compliance. The 206-12ST is appropriate only for applications with reduced electrical requirements (50mA at 24VDC or lower).

Q: Are all substitute parts washable?

A: Yes. Both 78B12ST and 206-12ST are washable with tape seal features, matching the 78B12S specification.

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