RT100AS33R0KB Equivalent & Substitute Parts

Part Overview

The RT100AS33R0KB is a 33 Ohm, 100W wirewound potentiometer manufactured by Vishay Sfernice, designed for panel mount applications with a 1-turn rotation and solder lug termination. This component is classified as obsolete, making it necessary to identify functionally equivalent alternatives for ongoing system maintenance and new designs requiring similar electrical and mechanical characteristics.

Key Parameters

Parameter	RT100AS33R0KB
Resistance (Ohms)	33
Power Rating (Watts)	100W
Tolerance	±10%
Number of Turns	1
Resistive Material	Wirewound
Termination Style	Solder Lug
Mounting Type	Panel Mount
Rotation	300°
Actuator Type	Round
Actuator Length	0.984" (25.00mm)
Actuator Diameter	0.236" (6.00mm)
Product Status	Obsolete

Substitute Part Grouping Explanation

Substitution of the RT100AS33R0KB is determined by the following critical parameters:

Resistance Value: 33 Ohms (±10% tolerance acceptable)
Power Rating: Minimum 100W; higher ratings provide design margin
Wirewound Construction: Required for thermal stability and power dissipation characteristics
Panel Mount Configuration: Solder lug termination with compatible actuator dimensions
Rotation Specification: 300° standard rotation
Number of Turns: 1-turn potentiometer

The substitute part RLS35RE from Ohmite meets these criteria with a 35 Ohm resistance value (within tolerance band for 33 Ohm applications), 150W power rating (exceeds minimum requirement), wirewound construction, panel mount design, and compatible mechanical interface.

Parameter Comparison

Parameter	RT100AS33R0KB (Vishay Sfernice)	RLS35RE (Ohmite)	Compatibility Notes
Resistance (Ohms)	33	35	2 Ohm variance within ±10% tolerance band
Power Rating (Watts)	100W	150W	Substitute exceeds minimum requirement
Tolerance	±10%	±10%	Matched specification
Number of Turns	1	1	Matched specification
Resistive Material	Wirewound	Wirewound	Matched specification
Termination Style	Solder Lug	Solder Lug	Matched specification
Mounting Type	Panel Mount	Panel Mount	Matched specification
Rotation	300°	300°	Matched specification
Actuator Type	Round	Flatted	Different actuator geometry; mechanical interface requires evaluation
Actuator Length	0.984" (25.00mm)	0.875" (22.23mm)	2.77mm shorter; panel cutout compatibility required
Actuator Diameter	0.236" (6.00mm)	0.250" (6.35mm)	0.35mm larger diameter
Product Status	Obsolete	Active	Substitute is in active production
RoHS Compliance	Not specified	ROHS3 Compliant	Substitute meets current environmental standards

Engineering Selection Recommendations

The RLS35RE from Ohmite is the manufacturer-recommended substitute for the obsolete RT100AS33R0KB. Selection of this alternative is supported by:

Active Product Status: RLS35RE is in active production, ensuring long-term availability and supply chain stability
Electrical Equivalence: 35 Ohm resistance falls within the ±10% tolerance band of the original 33 Ohm specification
Power Margin: 150W rating provides 50% additional capacity beyond the 100W requirement
Environmental Compliance: ROHS3 certification meets current regulatory requirements
Mechanical Compatibility: Panel mount configuration with solder lug termination and 300° rotation matches the original design intent

Mechanical interface verification is required due to differences in actuator geometry (flatted vs. round) and dimensional variations (length and diameter). Panel cutout dimensions and actuator engagement mechanisms must be evaluated for the specific application.

Frequently Asked Questions (FAQ)

Q: Can the RLS35RE directly replace the RT100AS33R0KB without circuit modifications?

A: The 2 Ohm resistance difference (33 Ohm to 35 Ohm) represents a 6% variance, which falls within the ±10% tolerance specification. For applications where resistance value is critical, circuit performance impact must be evaluated. The higher power rating (150W vs. 100W) does not require modification.

Q: What are the mechanical compatibility considerations?

A: The RLS35RE has a flatted actuator versus the round actuator of the RT100AS33R0KB. Actuator length differs by 2.77mm (0.875" vs. 0.984"), and diameter is 0.35mm larger (0.250" vs. 0.236"). Panel cutout dimensions, mounting bracket clearances, and actuator engagement mechanisms must be verified for the specific installation.

Q: Is the RLS35RE suitable for high-temperature applications?

A: Temperature coefficient information is not provided for either component in the available specifications. Thermal performance data must be obtained from manufacturer datasheets for applications with temperature-dependent requirements.

Q: What is the difference between the Taper specifications?

A: The RT100AS33R0KB does not specify a taper characteristic, while the RLS35RE is designated as Linear taper. This difference may affect the resistance-to-rotation relationship. Application requirements for taper type must be confirmed before substitution.

Q: Are there packaging differences between the original and substitute?

A: The RT100AS33R0KB is specified with packaging designation "-" (not provided), while the RLS35RE is supplied in Bulk packaging. Procurement and handling procedures may differ accordingly.

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