Ohmite 45F1K8 Equivalent & Substitute Parts

Part Overview

The Ohmite 45F1K8 is a 1.8 kOhms ±1% 5W through-hole resistor with axial wirewound construction, part of the Ohmicone® 40 series. This component is currently active in production and maintains 963 units in new original stock. The part is classified as RoHS non-compliant and is suitable for applications requiring precision resistive elements in axial package format. Substitute parts are identified to provide alternative sourcing options when the primary part becomes unavailable or when specific compliance requirements necessitate alternative components.

Substiute Parts

45F1K8

OhmiteIn Stock: 99945F1K8 Datasheet

Current PartRFQ

ALSR051K800FE12

Vishay DaleIn Stock: 1211ALSR051K800FE12 Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the Ohmite 45F1K8 are qualified based on the following critical parameters:

• Resistance Value: Must be 1.8 kOhms
• Tolerance: Must be ±1%
• Power Rating: Must be 5W
• Composition: Must be Wirewound
• Package: Must be Axial with 2 terminations
• Electrical Performance: Temperature coefficient and operating temperature range must support the intended application

The Vishay Dale ALSR051K800FE12 meets all mandatory electrical and mechanical substitution criteria. This part maintains identical resistance, tolerance, and power specifications while offering enhanced moisture resistance and improved RoHS compliance status.

Parameter Comparison

Engineering Selection Recommendations

Ohmite 45F1K8: Select this part when the original specification is required and RoHS non-compliance is acceptable for the application. Current inventory of 963 units supports immediate availability.

Vishay Dale ALSR051K800FE12: Select this substitute when RoHS3 compliance is mandated or when enhanced moisture resistance is required. The part offers superior environmental protection with MSL rating of 1 (Unlimited) and an extended operating temperature range of -65°C to 250°C. Physical dimensions are slightly smaller (0.312" Dia x 0.875" L versus 0.343" Dia x 0.937" L), which may provide layout advantages in space-constrained applications. The temperature coefficient of ±30ppm/°C is marginally higher than the primary part but remains within acceptable precision tolerances for most applications. Inventory availability is 1181 units.

Frequently Asked Questions (FAQ)

Q: Can the Vishay Dale ALSR051K800FE12 be used as a direct replacement for the Ohmite 45F1K8?

A: Yes, the Vishay Dale part is electrically and mechanically compatible. Both parts share identical resistance (1.8 kOhms), tolerance (±1%), power rating (5W), composition (wirewound), and package type (axial with 2 terminations). The substitute part is physically slightly smaller, which may require verification of PCB layout clearances in space-constrained designs.

Q: What is the significance of the temperature coefficient difference?

A: The Ohmite 45F1K8 has a temperature coefficient of ±20ppm/°C, while the Vishay Dale substitute is ±30ppm/°C. This 10ppm/°C difference is negligible for most applications and does not affect the ±1% tolerance specification. Selection should be based on the specific thermal stability requirements of the circuit.

Q: Why is RoHS compliance important for this substitution?

A: The Ohmite 45F1K8 is RoHS non-compliant, while the Vishay Dale ALSR051K800FE12 is ROHS3 compliant. If the end application or customer requirements mandate RoHS compliance, the Vishay Dale part is the appropriate selection. RoHS compliance affects material composition and environmental impact considerations.

Q: Are there any physical installation considerations when switching between these parts?

A: The Vishay Dale substitute is slightly smaller in diameter (0.312" versus 0.343") and length (0.875" versus 0.937"). Verify that PCB hole spacing, component clearances, and thermal management provisions accommodate the smaller dimensions. The axial lead configuration remains identical, so standard through-hole soldering processes apply to both parts.

Q: What does Moisture Sensitivity Level 1 (Unlimited) mean for the Vishay Dale part?

A: MSL 1 (Unlimited) indicates that the component has no moisture sensitivity restrictions and does not require special handling, storage, or baking procedures prior to soldering. This provides operational flexibility compared to components with higher MSL ratings.