Ohmite 45F3K9 Equivalent & Substitute Parts

Part Overview

The Ohmite 45F3K9 is a 3.9 kOhms ±1% 5W through-hole resistor with axial wirewound construction, part of the Ohmicone® 40 series. This component is currently active in production with 1101 pieces available in inventory. Equivalent and substitute parts are identified when electrical specifications, mechanical dimensions, and package compatibility align with the original design requirements, enabling seamless integration into existing circuits and assemblies.

Substiute Parts

45F3K9

OhmiteIn Stock: 117245F3K9 Datasheet

Current PartRFQ

45F3K9E

OhmiteIn Stock: 101245F3K9E Datasheet

DirectRFQ

ALSR053K900FE12

Vishay DaleIn Stock: 967ALSR053K900FE12 Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the Ohmite 45F3K9 are qualified based on the following criteria:

Electrical Parameters: Resistance value (3.9 kOhms), tolerance (±1%), and power rating (5W) must be identical. Temperature coefficient performance within acceptable engineering margins supports thermal stability equivalence.

Mechanical Parameters: Axial package configuration and physical dimensions must accommodate the same PCB footprint and mounting requirements. Wirewound composition ensures equivalent frequency response and noise characteristics.

Compliance & Status: Active product status confirms ongoing availability. RoHS compliance status is documented for each part to support regulatory requirements in target applications.

The following parts meet these substitution criteria:

• Ohmite 45F3K9E (direct manufacturer variant, bulk packaging, RoHS3 compliant)
• Vishay Dale ALSR053K900FE12 (alternative manufacturer, moisture-resistant variant, RoHS3 compliant)

Parameter Comparison

Engineering Selection Recommendations

Ohmite 45F3K9E: This part is a direct manufacturer equivalent from Ohmite with identical electrical and mechanical specifications. The primary distinction is RoHS3 compliance, making it suitable for applications requiring regulatory adherence. Bulk packaging aligns with production volume requirements.

Vishay Dale ALSR053K900FE12: This alternative manufacturer part maintains core electrical specifications (3.9 kOhms, ±1%, 5W) with RoHS3 compliance. The temperature coefficient is ±30ppm/°C compared to ±20ppm/°C for the primary part, representing a 50% increase in thermal drift. Physical dimensions are slightly smaller (0.312" Dia x 0.875" L versus 0.343" Dia x 0.937" L), which may require PCB layout verification. Moisture-resistant construction provides enhanced environmental protection. Operating temperature range (-65°C ~ 250°C) is specified, supporting extended thermal applications.

Selection between these substitutes depends on regulatory compliance requirements, thermal stability margins, and physical space constraints within the target assembly.

Frequently Asked Questions (FAQ)

Q: Can the Ohmite 45F3K9E be used as a direct replacement for the 45F3K9?

A: Yes. Both parts share identical resistance (3.9 kOhms), tolerance (±1%), power rating (5W), composition (wirewound), package type (axial), temperature coefficient (±20ppm/°C), and physical dimensions (0.343" Dia x 0.937" L). The primary difference is RoHS3 compliance status on the 45F3K9E variant.

Q: What are the implications of the Vishay Dale ALSR053K900FE12 having a ±30ppm/°C temperature coefficient versus ±20ppm/°C?

A: The ALSR053K900FE12 exhibits 50% greater thermal drift per degree Celsius. In applications with wide operating temperature ranges or stringent tolerance requirements, this difference may impact circuit performance. Thermal stability analysis is necessary to determine acceptability in specific designs.

Q: Are the physical dimensions of the Vishay Dale ALSR053K900FE12 compatible with the original PCB layout?

A: The ALSR053K900FE12 is slightly smaller (0.312" Dia x 0.875" L) compared to the original 45F3K9 (0.343" Dia x 0.937" L). While the axial package type remains compatible, PCB footprint verification is required to confirm fit within existing mounting holes and clearance constraints.

Q: What is the significance of the moisture-resistant feature on the Vishay Dale part?

A: The ALSR053K900FE12 includes moisture-resistant construction, providing enhanced protection in humid or corrosive environments. This feature is not present on the Ohmite variants and may be beneficial for applications exposed to elevated moisture levels or harsh operating conditions.

Q: Which substitute part should be selected for RoHS-compliant applications?

A: Both the Ohmite 45F3K9E and Vishay Dale ALSR053K900FE12 are RoHS3 compliant. The original 45F3K9 is RoHS non-compliant. Selection between the two compliant options depends on thermal coefficient requirements, physical space constraints, and environmental protection needs.