WMF4S33K Film Capacitor Equivalent & Substitute Parts

Part Overview

The WMF4S33K is a 0.033 µF polyester film capacitor rated for 400V DC operation in an axial through-hole package manufactured by Cornell Dubilier Electronics (CDE). This component is classified as obsolete, necessitating identification of active equivalent parts for ongoing procurement and design continuity. The WMF series represents a legacy product line, and locating functionally identical substitutes ensures system reliability and manufacturing continuity for applications requiring this specific capacitance and voltage rating.

Substiute Parts

WMF4S33K

Cornell Dubilier Electronics (CDE)In Stock: 834WMF4S33K Datasheet

Current PartRFQ

WMF4S33K-F

Cornell Dubilier Electronics (CDE)In Stock: 4184WMF4S33K-F Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the WMF4S33K is determined by strict equivalence across the following critical parameters:

Electrical Equivalence Requirements:

• Capacitance value: 0.033 µF (exact match)
• Capacitance tolerance: ±10% (exact match)
• Voltage rating: 400V DC minimum (exact match)
• Dielectric material: Polyester (exact match)

Mechanical Equivalence Requirements:

• Mounting technology: Through hole (exact match)
• Package configuration: Axial (exact match)
• Physical dimensions: 0.374" Dia × 0.874" L (exact match)
• Termination style: PC Pins (exact match)

Environmental Equivalence Requirements:

• Operating temperature range: -55°C to 125°C (exact match)
• Moisture sensitivity level: 1 (Unlimited) (exact match)

The WMF4S33K-F meets all substitution criteria as a direct equivalent from the same manufacturer series, with identical electrical and mechanical specifications. The primary distinction is product status and regulatory compliance.

Parameter Comparison

Engineering Selection Recommendations

Primary Substitute: WMF4S33K-F

The WMF4S33K-F is the direct functional equivalent of the WMF4S33K. Both components share identical electrical specifications (0.033 µF, ±10%, 400V DC), dielectric material (polyester), mechanical configuration (axial through-hole), and physical dimensions (9.50mm × 22.20mm).

The WMF4S33K-F is classified as an active product with current manufacturing status, ensuring long-term availability and supply chain continuity. The substitute part carries ROHS3 compliance certification, whereas the original WMF4S33K is RoHS non-compliant. This compliance upgrade is advantageous for applications subject to environmental regulations and procurement standards requiring RoHS-compliant components.

Both parts maintain identical operating temperature ranges (-55°C to 125°C) and moisture sensitivity ratings (MSL 1), confirming compatibility across environmental and storage conditions. The packaging difference (bulk versus standard) reflects inventory management and does not affect functional performance or circuit integration.

Selection of the WMF4S33K-F is appropriate for new designs, redesigns, and replacement procurement where component availability and regulatory compliance are considerations.

Frequently Asked Questions (FAQ)

Q: Can the WMF4S33K-F be used as a direct replacement for the WMF4S33K in existing circuit designs?

A: Yes. The WMF4S33K-F is electrically and mechanically identical to the WMF4S33K. Both components have the same capacitance (0.033 µF), tolerance (±10%), voltage rating (400V DC), dielectric material (polyester), and physical dimensions (9.50mm × 22.20mm). Direct substitution in PCB layouts and circuit schematics is supported without modification.

Q: What is the significance of the product status difference between these parts?

A: The WMF4S33K is classified as obsolete, indicating discontinued manufacturing and limited availability from existing inventory. The WMF4S33K-F is an active product with ongoing production, ensuring reliable procurement for current and future applications. For new designs and long-term supply requirements, the active WMF4S33K-F is the appropriate selection.

Q: Does the RoHS compliance difference affect circuit performance?

A: No. RoHS compliance relates to material composition and environmental regulations, not electrical or mechanical performance. Both the RoHS non-compliant WMF4S33K and the ROHS3-compliant WMF4S33K-F deliver identical functional performance. RoHS compliance becomes relevant when procurement standards, customer requirements, or regulatory frameworks mandate environmentally compliant components.

Q: Are the physical dimensions identical between these parts?

A: Yes. Both the WMF4S33K and WMF4S33K-F share identical physical dimensions of 0.374" diameter by 0.874" length (9.50mm × 22.20mm). PCB footprints, lead spacing, and mounting hole patterns are identical, supporting direct mechanical substitution without layout modifications.

Q: What is the difference between standard and bulk packaging?

A: Packaging designation reflects inventory and distribution format. Standard packaging typically includes individual component packaging and labeling. Bulk packaging consolidates multiple units for high-volume procurement. Both packaging formats contain identical components with identical electrical and mechanical specifications. Packaging selection is determined by procurement volume and inventory management requirements, not component performance.

Q: Are the operating temperature ranges equivalent?

A: Yes. Both parts operate across the identical temperature range of -55°C to 125°C. Thermal performance, derating characteristics, and environmental storage conditions are equivalent between the WMF4S33K and WMF4S33K-F.

Q: Can these parts be used interchangeably in high-reliability applications?

A: Both parts meet the same electrical and mechanical specifications required for general-purpose applications. The WMF4S33K-F, as an active product with current manufacturing status and ROHS3 compliance, is the appropriate selection for applications requiring long-term supply assurance and regulatory compliance documentation.