Adjustable Power Resistor

Image	Part Number	Description / PDF	Quantity	Rfq
	RSSD40370C27R0JB00 Vishay / Sfernice	SFERNICE FIXED RESISTORS	0
	RSSD13X70A27R0KB00 Vishay / Sfernice	ADJ PWR RES 27 OHM 42W CHAS MT	0
	RSSD16X94A39R0JB00 Vishay / Sfernice	ADJ PWR RES 39 OHM 70W CHAS MT	0
	RSSD25168C40R0JB00 Vishay / Sfernice	ADJ PWR RES 40 OHM 200W CHAS MT	0
	RSSD30250C1500JB00 Vishay / Sfernice	ADJ PWR RES 150 OHM 280W CHAS MT	0
	RSSD30250A4R70KB06 Vishay / Sfernice	ADJ PWR RES 4.7 OHM 280W CHAS MT	0
	RSSD25168CR120MB00 Vishay / Sfernice	ADJ PWR RES 120M OHM 200W CHAS	0
	RSSD30250A68R0JB00 Vishay / Sfernice	ADJ PWR RES 68 OHM 280W CHAS MT	0
	RSSD20117A8R20KB00 Vishay / Sfernice	ADJ PWR RES 8.2 OHM 100W CHAS MT	0
	RSSD20117A12R0JB00 Vishay / Sfernice	ADJ PWR RES 12 OHM 100W CHAS MT	0
	RSSD20117A11R0JB00 Vishay / Sfernice	ADJ PWR RES 11 OHM 100W CHAS MT	0
	RSSD25138C3R90KB00 Vishay / Sfernice	ADJ PWR RES 3.9 OHM 140W CHAS MT	0
	RSSD25138AR330MB06 Vishay / Sfernice	ADJ PWR RES 330M OHM 140W CHAS	0
	RSSD30250C1000JB00 Vishay / Sfernice	ADJ PWR RES 100 OHM 280W CHAS MT	0
	RSSD25168AR120MB06 Vishay / Sfernice	ADJ PWR RES 120M OHM 200W CHAS	0
	RSSD30250C1R80KB04 Vishay / Sfernice	ADJ PWR RES 1.8 OHM 280W CHAS MT	0
	RSSD08X34AR330MS00 Vishay / Sfernice	ADJ PWR RES 330M OHM 16W CHAS MT	0
	RSSD50373C1R50KB01 Vishay / Sfernice	SFERNICE FIXED RESISTORS	0
	RSSD16X94A68R0JB00 Vishay / Sfernice	ADJ PWR RES 68 OHM 70W CHAS MT	0
	RSSD30250CR270MB00 Vishay / Sfernice	ADJ PWR RES 270M OHM 280W CHAS	0

Adjustable Power Resistor

1. Overview

Potentiometers, variable resistors, and adjustable power resistors are three-terminal devices that allow manual or automated adjustment of electrical resistance. These components play a critical role in controlling voltage, current, and power in electronic circuits. Their ability to provide precise resistance tuning makes them essential in applications ranging from consumer electronics to industrial automation. Adjustable power resistors specifically handle high-power loads while maintaining stable performance.

2. Main Types and Functional Classification

Type	Functional Characteristics	Application Examples
Wirewound Potentiometer	High precision, high-temperature tolerance, durable	Power supply calibration, industrial motor control
Carbon Composition Potentiometer	Low cost, moderate noise, compact size	Audio volume control, consumer electronics
Digital Potentiometer	Digital interface, programmable resistance, no moving parts	Smart thermostats, IoT devices, medical equipment
Cermet Potentiometer	Stable resistance, low temperature coefficient	Aerospace systems, precision instrumentation
Adjustable Power Resistor	High power dissipation (up to 1000W), robust heat management	Electric vehicle charging, industrial heating systems

3. Structure and Composition

Typical components include:
- Resistive Element: Wirewound (nickel-chromium alloy), carbon film, or conductive plastic
- Wiper Contact: Gold-plated bronze or phosphor bronze for low contact resistance
- Housing: Flame-retardant plastic or metal casing for thermal protection
- Adjustment Mechanism: Rotary knob, linear slider, or digital control interface
- Terminals: Copper or brass terminals with solderable coatings

4. Key Technical Specifications

Parameter	Description	Importance
Resistance Range	Typically 10 to 10M for potentiometers, up to 100k for power resistors	Determines adjustability range
Power Rating	0.1W to 1000W depending on construction	Defines maximum power handling
Resolution	Analog: 0.1% step; Digital: 8-16 bit precision	Controls tuning accuracy
Temperature Coefficient	50-500 ppm/ C	Measures stability under thermal stress
Life Cycle	10,000-100,000 rotations (mechanical)	Determines durability

5. Application Fields

Consumer Electronics: Audio equipment (volume control), gaming controllers
Industrial: CNC machine calibration, process control systems
Automotive: Electric vehicle battery management, throttle position sensors
Medical: MRI machine parameter adjustment, infusion pump control
Renewable Energy: Solar inverter power optimization, wind turbine pitch control

6. Leading Manufacturers and Representative Products

Manufacturer	Product Series	Key Features
Bourns Inc.	3382P Series	Miniature trimmer potentiometer with 0.1% resolution
Vishay Precision Group	DHP10 Series	High-power wirewound resistor (1000W, 0.25% tolerance)
TE Connectivity	Precision Potentiometers	Military-grade cermet resistors (MIL-PRF-39023 qualified)
Analog Devices	AD5293 Digital Potentiometer	1024-position I C-controlled resistor ( 1% end-to-end tolerance)

7. Selection Guidelines

Key considerations:
- Power Requirements: Select resistors with 20% higher power rating than maximum load
- Environmental Conditions: Choose sealed enclosures for high-humidity environments
- Precision Needs: Use digital potentiometers for sub-1% accuracy requirements
- Cost Optimization: Balance wirewound (high cost, high durability) vs. carbon film (lower cost, shorter lifespan)
- Mounting Style: Through-hole for high vibration environments, surface-mount for PCB integration

8. Industry Trends

Future developments include:
- Miniaturization: 0402 package digital potentiometers entering mass production
- Smart Integration: IoT-enabled resistors with real-time resistance monitoring
- Material Innovation: Graphene-based resistive elements improving thermal stability by 40%
- Automated Adjustment: AI-controlled power resistors for dynamic load balancing
- Environmental Compliance: RoHS-compliant conductive plastics replacing cadmium-based compounds