Ohmite 43F39R Equivalent & Substitute Parts

Part Overview

The Ohmite 43F39R is a 3W, 39 Ohms ±1% through-hole axial wirewound resistor from the Ohmicone® 40 series, designed for applications requiring precision power resistors with stable performance across extended temperature ranges. This component is currently active in production with 908 units in stock. Equivalent and substitute parts are identified to support procurement flexibility, inventory management, and supply chain continuity when the primary part becomes unavailable or when alternative packaging configurations are required.

Substiute Parts

43F39R

OhmiteIn Stock: 97943F39R Datasheet

Current PartRFQ

43F39RE

OhmiteIn Stock: 77443F39RE Datasheet

DirectRFQ

ALSR0339R00FE12

Vishay DaleIn Stock: 1038ALSR0339R00FE12 Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the 43F39R are identified based on strict electrical and mechanical compatibility criteria. The primary substitution parameters are:

• Resistance value: 39 Ohms (exact match required)
• Tolerance: ±1% (exact match required)
• Power rating: 3W (exact match required)
• Composition: Wirewound (exact match required)
• Package: Axial through-hole (exact match required)
• Termination count: 2 leads (exact match required)

Two substitute parts meet these core electrical specifications:

1. 43F39RE (Ohmite): Direct manufacturer equivalent with identical electrical parameters. Differs only in packaging configuration (Bulk vs. Box) and RoHS compliance status.

2. ALSR0339R00FE12 (Vishay Dale): Cross-manufacturer substitute with matching electrical specifications. Physical dimensions are slightly smaller (0.180" Dia x 0.500" L vs. 0.220" Dia x 0.594" L), and temperature coefficient is ±30ppm/°C versus ±20ppm/°C. Includes moisture-resistant feature.

Parameter Comparison

Engineering Selection Recommendations

43F39RE (Ohmite): This part is the preferred direct substitute when RoHS compliance is required. It maintains identical electrical specifications and physical dimensions to the 43F39R, with the primary difference being packaging format (Bulk vs. Box) and RoHS Compliant status. Selection of this part is appropriate for applications subject to RoHS regulations or when maintaining exact dimensional compatibility is critical.

ALSR0339R00FE12 (Vishay Dale): This cross-manufacturer substitute is suitable for applications where compact form factor is advantageous. The smaller physical dimensions (0.180" Dia x 0.500" L) may provide space savings in PCB layouts. The temperature coefficient of ±30ppm/°C is slightly higher than the 43F39R (±20ppm/°C), and the maximum operating temperature is 250°C versus 275°C. The inclusion of moisture-resistant features provides additional environmental protection. This part is appropriate for applications where these parameter variations are acceptable and where Vishay Dale supply chain access is preferred.

Frequently Asked Questions (FAQ)

Q: Can the 43F39RE be used as a direct replacement for the 43F39R?

A: Yes. The 43F39RE is electrically and mechanically identical to the 43F39R. The only differences are packaging configuration (Bulk vs. Box) and RoHS compliance status. Both parts have identical resistance (39 Ohms ±1%), power rating (3W), temperature coefficient (±20ppm/°C), operating temperature range (-55°C ~ 275°C), and physical dimensions (0.220" Dia x 0.594" L).

Q: What are the key differences between the Ohmite 43F39R and the Vishay Dale ALSR0339R00FE12?

A: Both parts share identical electrical specifications: 39 Ohms ±1%, 3W power rating, wirewound composition, and axial package. The ALSR0339R00FE12 differs in three areas: (1) physical dimensions are smaller (0.180" Dia x 0.500" L vs. 0.220" Dia x 0.594" L), (2) temperature coefficient is ±30ppm/°C versus ±20ppm/°C, and (3) maximum operating temperature is 250°C versus 275°C. The ALSR0339R00FE12 includes moisture-resistant features.

Q: Are there any PCB layout considerations when substituting the ALSR0339R00FE12 for the 43F39R?

A: Yes. The ALSR0339R00FE12 has smaller physical dimensions (0.180" Dia x 0.500" L) compared to the 43F39R (0.220" Dia x 0.594" L). This smaller form factor may require PCB footprint adjustment. Both parts use identical axial lead terminations, so lead spacing compatibility should be verified against your specific PCB design.

Q: Which substitute part should I select for RoHS-compliant applications?

A: The 43F39RE is RoHS Compliant and is the appropriate selection for applications subject to RoHS regulations. It maintains all electrical and mechanical specifications of the 43F39R while meeting RoHS compliance requirements.

Q: How do temperature coefficients affect part selection?

A: The 43F39R and 43F39RE both have a temperature coefficient of ±20ppm/°C, while the ALSR0339R00FE12 has ±30ppm/°C. In applications requiring high precision across temperature variations, the lower temperature coefficient of the Ohmite parts provides better resistance stability. The ALSR0339R00FE12 is suitable for applications where this higher coefficient is within acceptable tolerance limits.

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

A: The 43F39R and 43F39RE operate from -55°C to 275°C. The ALSR0339R00FE12 operates from -65°C to 250°C. For applications requiring operation above 250°C, the Ohmite parts are required.