Grayhill 78B03 DIP Switch Equivalent & Substitute Parts

Part Overview

The Grayhill 78B03 is a single-pole single-throw (SPST) slide-actuated DIP switch rated for 150mA at 30VDC with a 3-position configuration. This component is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and production continuity. The 78B03 features through-hole mounting with PC pin termination, gold-plated copper alloy contacts, and operates across a temperature range of -40°C to 85°C. Substitute parts must maintain functional compatibility while accounting for differences in electrical ratings, mechanical specifications, and compliance certifications.

Key Parameters

Parameter	Value
Circuit Configuration	SPST (Single-Pole Single-Throw)
Number of Positions	3
Current Rating	150mA
Voltage Rating	30VDC
Actuator Type	Slide (Standard)
Mounting Type	Through Hole
Termination Style	PC Pin
Pitch	0.100" (2.54mm)
Operating Temperature Range	-40°C to 85°C
Contact Material	Copper Alloy
Contact Finish	Gold
Height Above Board	0.315" (8.00mm)
Mechanical Life	2,000 Cycles
Electrical Life	2,000 Cycles

Substitute Part Grouping Explanation

Substitution logic for the Grayhill 78B03 is based on the following critical parameters that determine functional compatibility:

Primary Compatibility Criteria:

Circuit configuration (SPST)
Number of positions (3)
Actuator type (Slide Standard)
Mounting type (Through Hole)
Termination style (PC Pin)
Pitch spacing (0.100" / 2.54mm)

Secondary Compatibility Criteria:

Current rating (must equal or exceed 150mA for direct substitution)
Voltage rating (must equal or exceed 30VDC for direct substitution)
Operating temperature range (-40°C to 85°C minimum)
Contact finish (Gold preferred for reliability)

Substitute Classification:

Direct Equivalent: 78B03T (Grayhill Inc.) — Identical electrical and mechanical specifications with active product status and improved RoHS3 compliance.

Functional Substitute with Derating: 206-3 (CTS Electrocomponents) — Maintains SPST 3-position configuration and through-hole mounting but operates at reduced current (50mA) and voltage (24VDC) ratings. Suitable only for applications within these lower electrical parameters.

Functional Substitute with Derating: BD03 (C&K) — Maintains SPST 3-position configuration and through-hole mounting but operates at reduced voltage (5VDC) and current (100mA) ratings. Suitable only for applications within these lower electrical parameters.

Parameter Comparison

Parameter	78B03 (Main)	78B03T (Grayhill)	206-3 (CTS)	BD03 (C&K)
Manufacturer	Grayhill Inc.	Grayhill Inc.	CTS Electrocomponents	C&K
Product Status	Obsolete	Active	Active	Active
Circuit	SPST	SPST	SPST	SPST
Positions	3	3	3	3
Current Rating	150mA	150mA	50mA	100mA
Voltage Rating	30VDC	30VDC	24VDC	5VDC
Actuator Type	Slide (Standard)	Slide (Standard)	Slide (Standard)	Slide (Standard)
Mounting Type	Through Hole	Through Hole	Through Hole	Through Hole
Termination Style	PC Pin	PC Pin	PC Pin	PC Pin
Pitch	0.100" (2.54mm)	0.100" (2.54mm)	0.100" (2.54mm)	0.100" (2.54mm)
Height Above Board	0.315" (8.00mm)	0.315" (8.00mm)	0.334" (8.48mm)	0.297" (7.54mm)
Operating Temperature	-40°C to 85°C	-40°C to 85°C	-55°C to 85°C	-40°C to 85°C
Contact Material	Copper Alloy	Copper Alloy	Not Specified	Phosphor Bronze
Contact Finish	Gold	Gold	Gold	Gold
Mechanical Life	2,000 Cycles	2,000 Cycles	Not Specified	10,000 Cycles
Electrical Life	2,000 Cycles	2,000 Cycles	10,000 Cycles	10,000 Cycles
RoHS Status	Non-compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Packaging	Bulk	Tube	Tube	Tube

Engineering Selection Recommendations

For Direct Replacement (Recommended):

The 78B03T from Grayhill Inc. is the preferred substitute for the obsolete 78B03. This part maintains identical electrical ratings (150mA at 30VDC), mechanical specifications, and physical footprint. The 78B03T is currently in active production status with ROHS3 compliance certification, providing superior supply chain continuity and regulatory alignment compared to the original obsolete part. No circuit redesign or board layout modification is required.

For Reduced-Specification Applications:

The 206-3 (CTS Electrocomponents) and BD03 (C&K) are functional substitutes only for applications operating within their respective lower electrical ratings. The 206-3 is suitable for circuits requiring maximum 50mA at 24VDC or lower. The BD03 is suitable for circuits requiring maximum 100mA at 5VDC or lower. Both parts maintain the same SPST 3-position slide-actuated configuration and through-hole PC pin termination, ensuring mechanical and footprint compatibility. Both are ROHS3 compliant and currently in active production.

Compliance Considerations:

All substitute parts (78B03T, 206-3, BD03) carry ROHS3 compliance certification, addressing regulatory requirements that the original 78B03 does not meet. REACH status is unaffected across all parts. All parts are classified under ECCN EAR99 and HTSUS 8536.50.9065.

Frequently Asked Questions (FAQ)

Q: Can the 78B03T be used as a direct replacement for the 78B03 without circuit modification?

A: Yes. The 78B03T is a direct equivalent with identical electrical ratings (150mA, 30VDC), mechanical specifications, and physical dimensions. No circuit redesign is required. The part maintains the same SPST 3-position configuration, slide actuator, through-hole mounting, and PC pin termination.

Q: What is the primary difference between the 78B03 and 78B03T?

A: The 78B03T is the active production variant of the 78B03 series. Both parts are electrically and mechanically identical. The 78B03T carries ROHS3 compliance certification, while the original 78B03 is RoHS non-compliant. The 78B03T is packaged in tubes rather than bulk.

Q: Can the 206-3 or BD03 be used in place of the 78B03?

A: The 206-3 and BD03 are functional substitutes only for applications operating within their reduced electrical ratings. The 206-3 is limited to 50mA at 24VDC maximum. The BD03 is limited to 100mA at 5VDC maximum. If your circuit requires the full 150mA at 30VDC capability of the 78B03, these parts are not suitable without circuit redesign and component derating analysis.

Q: Are there any physical footprint differences between these substitute parts?

A: All four parts maintain the same 0.100" (2.54mm) pitch and through-hole PC pin termination, ensuring PCB compatibility. Height above board varies slightly: 78B03 and 78B03T are 0.315" (8.00mm), 206-3 is 0.334" (8.48mm), and BD03 is 0.297" (7.54mm). These minor variations do not affect standard through-hole board layouts.

Q: Which substitute part offers the longest mechanical and electrical life?

A: The BD03 (C&K) offers the longest operational life with 10,000 mechanical cycles and 10,000 electrical cycles, compared to 2,000 cycles for both the 78B03 and 78B03T. The 206-3 specifies 10,000 electrical cycles with mechanical life not specified. For applications requiring extended cycle life, the BD03 is advantageous if electrical ratings are compatible with your design.

Q: Are all substitute parts RoHS compliant?

A: Yes. The 78B03T, 206-3, and BD03 all carry ROHS3 compliance certification. The original 78B03 is RoHS non-compliant. For new designs or regulatory compliance requirements, any of the three substitute parts satisfy RoHS3 standards.

Q: What is the operating temperature range for each part?

A: The 78B03, 78B03T, and BD03 all operate from -40°C to 85°C. The 206-3 offers an extended lower temperature range of -55°C to 85°C, providing superior performance in cold-environment applications.

Q: Can these parts be used interchangeably in existing inventory?

A: The 78B03T can be used interchangeably with the 78B03 without any restrictions. The 206-3 and BD03 can be used interchangeably with each other only in applications where both the reduced current and voltage ratings are acceptable. Cross-substitution between the 78B03/78B03T group and the 206-3/BD03 group requires circuit analysis to confirm electrical compatibility.

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