Variable Resistors
Variable resistors are passive components that allow resistance to be adjusted manually or mechanically, enabling engineers to set, trim, or continuously control voltage, current, and signal levels within a circuit. Unlike fixed resistors, they serve a dual role: potentiometers function as three-terminal voltage dividers for signal-level control and calibration adjustment, while rheostats operate as two-terminal high-power devices for direct current and power regulation in demanding industrial systems.
RARA variable resistors span four technologies — carbon potentiometers, cermet potentiometers, precision wire wound potentiometers, and wire wound power rheostats — covering power ratings from 0.1W up to 3000W and resistance values from 22Ω to 4.7MΩ. The carbon PR series provides economical panel control for general-purpose applications, while the hermetically sealed PC-199 and CW-18 cermet models resist moisture and contamination in outdoor and harsh-environment installations. The DM, DOW, and DG precision wire wound potentiometers deliver the accuracy and repeatability required for calibration and instrumentation duties, and the BC1 wire wound rheostat handles continuous power loads up to 3000W for industrial motor control, resistance welding, and electrolysis equipment.
Compared to fixed resistor networks or digital potentiometers, RARA's mechanical variable resistor range offers immediate tactile adjustment, no supply voltage requirement, and proven long-term reliability in environments from PCB-level trimming applications all the way to heavy industrial power control — all from a single ISO 9001 and IATF 16949 certified supplier.
Passive three-terminal components for adjustable resistance — carbon and cermet potentiometers for signal-level control, precision wire wound potentiometers for calibration and instrumentation, and heavy-duty wire wound rheostats rated up to 3000W for industrial power control.
22Ω – 4.7MΩ
Resistance Range
Technologies:
Potentiometer
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Rheostat
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Cermet
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Precision
What Is a Variable Resistor?
A practical overview for engineers and procurement teams evaluating resistive solutions.
A
variable resistor
is a passive component that allows resistance to be adjusted manually or mechanically — as opposed to a fixed resistor whose value is set at manufacture. RARA's variable resistor range covers two fundamental types:
potentiometers, which are three-terminal voltage dividers used for signal-level control and adjustment, and rheostats, which are two-terminal high-power variable resistors used for current and power control in industrial systems.
At the low-power end, carbon potentiometers
(PR-16, PR-18, PR-24, SP) provide economical, reliable adjustment for audio, lighting, and general-purpose control circuits.
Cermet potentiometers
(CN-15, PC-199, CW-18) offer improved stability and longer service life than carbon types — the PC-199 and CW-18 are hermetically sealed for use in demanding environments.
Precision wire wound potentiometers
(DM, DOW, DG) deliver the accuracy needed for calibration, instrumentation, and closed-loop control applications.
At the high-power end, the
BC1 wire wound rheostat
series handles 25W to 3000W of continuous power — used for motor speed control, current limiting, and power regulation in heavy industrial equipment where large, stepless resistance adjustment is required.
Construction Technologies
-Carbon potentiometers (PR-16, PR-18, PR-24, SP)
-Cermet potentiometers (CN-15, CW-18)
-Hermetic cermet potentiometer (PC-199)
-Precision wire wound potentiometers (DM, DOW, DG)
-Wire wound power rheostat (BC1 — up to 3000W)
Key Advantages
-Full range from signal-level to 3000W power control
-Hermetically sealed cermet models for harsh environments
-Precision wire wound types for calibration use
-Wide resistance range: 22Ω to 4.7MΩ
-ISO 9001 and IATF 16949 certified manufacturer
RARA variable resistors come in potentiometer and rheostat designs — from compact 15mm cermet trimmers at 1W to massive 3000W industrial wire wound rheostats for heavy-duty power control.
Where RARA variable resistors are deployed in the field.
General Purpose Signal Control
Carbon potentiometers (PR-16, PR-18, PR-24) are the standard choice for volume controls, brightness adjustment, speed setting knobs, and general-purpose panel control in consumer electronics, industrial HMIs, and test equipment — offering wide resistance range up to 4.7MΩ in a compact rotary format.
Calibration & Instrumentation
Precision wire wound potentiometers (DM, DOW, DG) with tolerances to ±2% and stable wire wound elements are used for calibration adjustments, setpoint controls, and feedback trimming in measurement instruments, process controllers, and analog signal conditioning circuits where repeatability over time is essential.
Harsh & Sealed Environments
The PC-199 and CW-18 hermetically sealed cermet potentiometers resist moisture, dust, and contamination — making them suitable for outdoor control panels, marine equipment, military systems, and industrial machinery where an unsealed potentiometer would fail due to environmental ingress.
Industrial Motor Speed Control
The BC1 wire wound rheostat (25W–3000W, 1Ω–10kΩ) is used for direct current control in DC motor drives, resistance welding machines, electrolysis equipment, and industrial heating elements — where smooth, stepless power adjustment over a large range is required continuously.
Lighting & Dimming Control
Carbon and cermet potentiometers serve as dimmer controls in theatrical lighting, industrial LED drivers, and laboratory illumination systems. The CN-15 trimming cermet type is particularly suited to PCB-level brightness adjustment where the control is set once and not frequently changed.
Laboratory & Test Equipment
Precision wire wound potentiometers (DOW at 4W, ±2–5%) provide the power handling and accuracy needed for variable load simulation, resistance substitution boxes, and adjustable reference circuits in laboratory power supplies, impedance bridges, and electronic test fixtures.
Select models from our variable lineup. Download individual datasheets for full specifications, dimensions, and ordering codes.
Model: CN-15
Resistor type: Variable
Description: 15mm, trimming cermet potentiometer
Power Rating: 1W
Resistance (Ω): E6, 100~4.7M
Tolerance (%): ±20, ±30
TCR (ppm/C): 300
Model: PR-16
Resistor type: Variable
Description: 16mm, carbon single turn potentiometer
Power Rating: 0.1W
Resistance (Ω): E3, 100~10k
Tolerance (%): ±5, ±10, ±20, ±30
Model: PR-18
Resistor type: Variable
Description: 18.5mm, carbon single turn potentiometer
Power Rating: 0.2W
Resistance (Ω): E3, 120~2.2M
Tolerance (%): ±5, ±10, ±20, ±30
Model: PR-24
Resistor type: Variable
Description: 24mm, carbon single turn potentiometer
Power Rating: 0.5W
Resistance (Ω): E3, 100~1M
Tolerance (%): ±5, ±10, ±20, ±30
Model: PC-199
Resistor type: Variable
Description: 19mm, hermetic cermet potentiometer
Power Rating: 1W
Resistance (Ω): 100~2.2M
Tolerance (%): ±10, ±20, ±30
Model: SP
Resistor type: Variable
Description: 29mm, carbon single turn potentiometer
Power Rating: 1W
Resistance (Ω): 10kR (E6)
Tolerance (%): ±10
Model: CW-18
Resistor type: Variable
Description: 18.5mm, hermetic cermet potentiometer
Power Rating: 1W
Resistance (Ω): 100~2.2M
Tolerance (%): 20, ±30
TCR (ppm/C): 300
Model: DM
Resistor type: Variable
Description: Wire wound potentiometer
Power Rating: 0.75W
Resistance (Ω): 22~47k
Tolerance (%): ±2.5, ±5, ±10
Model: DOW
Resistor type: Variable
Description: Wire wound potentiometer
Power Rating: 4W
Resistance (Ω): 22~47k
Tolerance (%): ±2, ±5
Model: DG
Resistor type: Variable
Description: Wire wound potentiometer
Power Rating: 2W
Resistance (Ω): 22~3.3k
Tolerance (%): ±5, ±10
Model: BC1
Resistor type: Variable
Description: Variable power rheostat
Power Rating: 12.5W~150W
Resistance (Ω): 0.5~5.1k
Tolerance (%): ±5, ±10
TCR (ppm/C): 200~400
Model: BSR/BSQ
Resistor type: Variable
Description: Slide type variable power resistor
Power Rating: 200W~2000W
Resistance (Ω): 0.5~200 max.
Tolerance (%): ±10
Why Choose RARA Variable Resistors
What sets RARA apart for engineers and procurement managers in industrial and automotive markets.
01
Full Spectrum Coverage
From 0.1W carbon signal potentiometers to 3000W industrial wire wound rheostats — RARA covers the complete variable resistor spectrum from a single ISO 9001 certified supplier.
02
Hermetic Sealed Options
PC-199 and CW-18 hermetically sealed cermet models resist moisture, dust, and contamination — extending service life in outdoor, marine, and industrial environments where standard potentiometers degrade rapidly.
03
Precision Wire Wound
DM, DOW, and DG precision wire wound potentiometers deliver the accuracy and repeatability needed for calibration, instrumentation, and closed-loop feedback applications.
04
Global Track Record
Trusted by Siemens, Rockwell, Schneider Electric, and Hanwha — deployed in industrial control and power regulation systems across six continents.
