Adjustable Power Resistor

Part Number	Description / PDF	Quantity
RSSD25138A2R20KB00 Vishay / Sfernice	ADJ PWR RES 2.2 OHM 140W CHAS MT	0
D75K200E Ohmite	RESISTOR POWER ADJ 200 OHM 75W	0
RSSD16X94A3R90KB19 Vishay / Sfernice	ADJ PWR RES 3.9 OHM 70W CHAS MT	0
D12K1K25E Ohmite	RESISTOR POWER ADJ 1.25K OHM 12W	0
RSSD25168C9R10KB00 Vishay / Sfernice	ADJ PWR RES 9.1 OHM 200W CHAS MT	0
D225K2K5E Ohmite	RESISTOR POWER ADJ 2.5K OHM 225W	0
RSSD30250A1000JB06 Vishay / Sfernice	ADJ PWR RES 100 OHM 280W CHAS MT	6
RSSD25138AR220MB00 Vishay / Sfernice	ADJ PWR RES 220M OHM 140W CHAS	0
RSSD25168A51R0JB06 Vishay / Sfernice	ADJ PWR RES 51 OHM 200W CHAS MT	0
D50K1R0 Ohmite	RESISTOR POWER ADJ 1 OHM 50W	0
RSSD30250C1800JB04 Vishay / Sfernice	ADJ PWR RES 180 OHM 280W CHAS MT	0
RSSD20117A15R0JB00 Vishay / Sfernice	ADJ PWR RES 15 OHM 100W CHAS MT	0
D225K30RE Ohmite	225W 30 OHMS VIT 0.1	5
D25K10R Ohmite	RESISTOR POWER ADJ 10 OHM 25W	4
D12K8K5 Ohmite	RESISTOR POWER ADJ 8.5K OHM 12W	0
D75K10KE Ohmite	RESISTOR POWER ADJ 10K OHM 75W	0
RSSD40370C4R70KB00 Vishay / Sfernice	SFERNICE FIXED RESISTORS	0
D225K30K Ohmite	RESISTOR POWER ADJ 30K OHM 225W	0
D75K4K0E Ohmite	RESISTOR POWER ADJ 4K OHM 75W	0
D12K400E Ohmite	RESISTOR POWER ADJ 400 OHM 12W	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