WMF1W1K-F Equivalent & Substitute Parts

Part Overview

The WMF1W1K-F is a 1 µF film capacitor manufactured by Cornell Dubilier Electronics (CDE) with a 100V DC voltage rating and ±10% tolerance. This polyester dielectric axial component is designed for general-purpose applications requiring through-hole mounting. The part is currently in active production status with 1026 units available in inventory. Substitute parts are identified when equivalent electrical specifications and mechanical compatibility are maintained across the allowed parameter range for this capacitor category.

Key Parameters

Parameter	Value	Substitution Relevance
Capacitance	1 µF	Critical - must match exactly
Voltage Rating (DC)	100V	Critical - must meet or exceed
Tolerance	±10%	Critical - must match or be tighter
Dielectric Material	Polyester	Critical - determines electrical characteristics
Mounting Type	Through Hole	Critical - determines PCB compatibility
Package / Case	Axial	Critical - determines physical fit
Operating Temperature Range	-55°C ~ 125°C	Important - defines environmental limits
RoHS Status	ROHS3 Compliant	Important - regulatory compliance

Substitute Part Grouping Explanation

Substitute parts for the WMF1W1K-F are identified based on strict equivalence of the following parameters:

Critical Matching Parameters:

Capacitance value: 1 µF (exact match required)
Voltage rating: 100V DC minimum (equal or higher acceptable)
Tolerance: ±10% or tighter
Dielectric type: Polyester film
Mounting configuration: Through-hole axial

Acceptable Variations:

Physical dimensions may differ while maintaining axial through-hole compatibility
Operating temperature range may vary (substitute range must encompass application requirements)
Dielectric construction may include metallized polyester variants
ESR and other secondary electrical parameters may differ

Regulatory Compliance:

RoHS3 compliance required
REACH unaffected status maintained

The substitute part 105MWR100K meets all critical matching parameters while offering a more compact physical form factor and lower ESR characteristics.

Parameter Comparison

Parameter	WMF1W1K-F (Main Part)	105MWR100K (Substitute)	Compatibility Status
Manufacturer	Cornell Dubilier Electronics	Cornell Dubilier / Illinois Capacitor	Compatible
Capacitance	1 µF	1 µF	Exact Match
Tolerance	±10%	±10%	Exact Match
Voltage Rating (DC)	100V	100V	Exact Match
Voltage Rating (AC)	Not specified	63V	Substitute provides additional specification
Dielectric Material	Polyester	Polyester, Metallized	Compatible - metallized variant
Mounting Type	Through Hole	Through Hole	Exact Match
Package / Case	Axial	Axial	Exact Match
Size / Dimension	0.669" Dia x 1.500" L (17.00mm x 38.10mm)	0.374" Dia x 0.748" L (9.50mm x 19.00mm)	Substitute is more compact
Operating Temperature	-55°C ~ 125°C	-40°C ~ 105°C	Substitute has narrower range
ESR (Equivalent Series Resistance)	Not specified	1.415 Ohms	Substitute provides lower ESR
Termination	PC Pins	PC Pins	Exact Match
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	Exact Match
REACH Status	REACH Unaffected	REACH Unaffected	Exact Match
Product Status	Active	Active	Both in production

Engineering Selection Recommendations

Primary Selection (WMF1W1K-F): Use the WMF1W1K-F when the extended operating temperature range of -55°C to 125°C is required. This part maintains active production status and is ROHS3 compliant with REACH unaffected designation.

Substitute Selection (105MWR100K): The 105MWR100K serves as a functional equivalent when:

PCB space constraints favor a more compact form factor (9.50mm diameter vs. 17.00mm)
Lower ESR characteristics (1.415 Ohms) are beneficial for the application
Operating temperature requirements fall within -40°C to 105°C range
Metallized polyester dielectric properties are acceptable

Both parts maintain identical capacitance, tolerance, DC voltage rating, and through-hole axial mounting configuration. Both are ROHS3 compliant and REACH unaffected. Selection between these parts depends on thermal environment requirements and physical space availability on the PCB.

Frequently Asked Questions (FAQ)

Q: Can 105MWR100K replace WMF1W1K-F in all applications?

A: The 105MWR100K is electrically equivalent for applications operating within -40°C to 105°C. Applications requiring operation below -40°C or above 105°C must use the WMF1W1K-F, which is rated to -55°C to 125°C.

Q: What is the physical difference between these parts?

A: The WMF1W1K-F measures 0.669" diameter by 1.500" length (17.00mm x 38.10mm). The 105MWR100K measures 0.374" diameter by 0.748" length (9.50mm x 19.00mm). Both are axial through-hole components with PC pin termination. The substitute is approximately 56% smaller in diameter and 50% shorter in length.

Q: Are both parts RoHS compliant?

A: Yes. Both WMF1W1K-F and 105MWR100K are ROHS3 compliant and REACH unaffected.

Q: What does "metallized" mean in the dielectric material specification?

A: The 105MWR100K uses metallized polyester film, where a thin metal layer is applied to the polyester surface. This construction typically results in lower ESR and more compact packaging compared to standard polyester film capacitors.

Q: Can I use the substitute in a high-temperature application rated to 125°C?

A: No. The 105MWR100K is rated only to 105°C maximum operating temperature. For applications requiring 125°C operation, the WMF1W1K-F must be used.

Q: Do both parts have the same lead spacing?

A: Lead spacing is not specified in the provided data for either part. Physical dimensions are provided; verify mechanical fit in your specific PCB layout before substitution.

Q: What is the inventory status for substitution planning?

A: WMF1W1K-F has 1026 units in stock. 105MWR100K has 2036 units in stock. Both are active production parts.

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