UB3C-4RF8 Equivalent & Substitute Parts

Part Overview

The Riedon UB3C-4RF8 is a 4 Ohm ±1% 3W axial wirewound resistor designed for current sensing applications. This through-hole component features flame-proof, moisture-resistant, pulse-withstanding, and safety-rated construction, operating across -55°C to 250°C. The part is currently active in production and ROHS3 compliant. Substitute parts are identified when equivalent electrical specifications, mechanical compatibility, and regulatory certifications align with the original design requirements.

Key Parameters

Parameter	Value
Resistance	4 Ohms
Tolerance	±1%
Power Rating	3W
Composition	Wirewound
Package Type	Axial
Temperature Coefficient	±50ppm/°C
Operating Temperature Range	-55°C ~ 250°C
Terminations	2
RoHS Status	ROHS3 Compliant
Moisture Sensitivity Level	1 (Unlimited)

Substitute Part Grouping Explanation

Substitute parts for the UB3C-4RF8 are qualified based on the following criteria:

Electrical Parameters: Resistance value of 4 Ohms, tolerance of ±1%, power rating of 3W, and temperature coefficient of ±50ppm/°C must match exactly.

Mechanical Parameters: Axial package configuration with 2 terminations is required for direct board-level compatibility.

Composition: Wirewound construction is mandatory for current sensing applications and thermal stability.

Regulatory Compliance: ROHS3 compliance and EAR99 ECCN classification must be maintained.

Operating Temperature: Substitute parts must support the minimum operating range of -55°C to 250°C, though extended ranges are acceptable.

All three substitute parts meet these criteria and are manufacturer-recommended alternatives.

Parameter Comparison

Parameter	UB3C-4RF8 (Riedon)	43F4R0E (Ohmite)	ALSR034R000FE12 (Vishay Dale)	WW3FT4R00 (Stackpole)
Resistance	4 Ohms	4 Ohms	4 Ohms	4 Ohms
Tolerance	±1%	±1%	±1%	±1%
Power Rating	3W	3W	3W	3W
Composition	Wirewound	Wirewound	Wirewound	Wirewound
Temperature Coefficient	±50ppm/°C	±50ppm/°C	±50ppm/°C	±50ppm/°C
Operating Temperature	-55°C ~ 250°C	Not Specified	-65°C ~ 250°C	-55°C ~ 350°C
Package / Case	Axial	Axial	Axial	Axial
Size / Dimension	0.157" Dia x 0.350" L (4.00mm x 8.90mm)	0.220" Dia x 0.594" L (5.60mm x 15.10mm)	0.180" Dia x 0.500" L (4.57mm x 12.70mm)	0.187" Dia x 0.560" L (4.75mm x 14.22mm)
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Moisture Sensitivity Level	1 (Unlimited)	Not Applicable	1 (Unlimited)	Not Applicable
Product Status	Active	Active	Active	Active

Engineering Selection Recommendations

All three substitute parts are active products with ROHS3 compliance and EAR99 ECCN classification, meeting regulatory requirements equivalent to the original UB3C-4RF8.

43F4R0E (Ohmite Ohmicone® 40 Series): Electrically equivalent with matching specifications. Physical dimensions are larger (0.220" diameter). Suitable for applications where board space permits. Bulk packaging available.

ALSR034R000FE12 (Vishay Dale ALSR Series): Electrically equivalent with extended lower operating temperature limit (-65°C vs. -55°C). Compact form factor (0.180" diameter) closest to the original. Moisture-resistant construction. Bulk packaging available.

WW3FT4R00 (Stackpole Electronics WW Series): Electrically equivalent with extended upper operating temperature limit (350°C vs. 250°C). Moderate physical dimensions (0.187" diameter). Highest inventory availability (4714 pcs). Cut tape packaging available.

Selection should prioritize physical dimensions relative to PCB layout constraints and packaging requirements for procurement workflows.

Frequently Asked Questions (FAQ)

Q: Can these substitute parts be used interchangeably with the UB3C-4RF8?

A: Yes, all three substitute parts meet the electrical and mechanical specifications required for direct substitution. Electrical parameters (resistance, tolerance, power rating, temperature coefficient) are identical. All use axial package configuration with 2 terminations. Physical dimensions vary, requiring verification of PCB layout compatibility.

Q: What are the key differences between the substitute parts?

A: Primary differences are physical dimensions and operating temperature ranges. The Vishay Dale ALSR034R000FE12 offers the most compact form factor. The Stackpole WW3FT4R00 provides the highest operating temperature ceiling (350°C). The Ohmite 43F4R0E has the largest diameter. All maintain identical electrical performance.

Q: Are there packaging format differences?

A: Yes. The original UB3C-4RF8 is supplied in Tape & Reel (TR) format. The Ohmite 43F4R0E and Vishay Dale ALSR034R000FE12 are available in Bulk packaging. The Stackpole WW3FT4R00 is available in Cut Tape (CT) format. Packaging selection depends on procurement and assembly requirements.

Q: Do all substitutes maintain the same moisture resistance properties?

A: The original UB3C-4RF8 and Vishay Dale ALSR034R000FE12 both specify Moisture Sensitivity Level 1 (Unlimited). The Ohmite 43F4R0E and Stackpole WW3FT4R00 list MSL as Not Applicable, indicating different moisture handling classifications. For moisture-critical applications, the Vishay Dale part maintains direct equivalence.

Q: Which substitute offers the best inventory availability?

A: The Stackpole Electronics WW3FT4R00 has the highest inventory level at 4714 pcs, compared to 932 pcs (Ohmite) and 913 pcs (Vishay Dale).

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