CW-18 Series Thick Film Cermet Rotary Potentiometers
Thick film cermet rotary potentiometer with 18.5mm metal housing diameter
Thick film layered resistance track deposited on ceramic base with isolated rotor and carbon wiper, actuated by metal spindle
Metal housing profiled to act as a heatsink for improved thermal management
Resistance range 100Ω to 2.2MΩ (E6 series values), linear characteristic (A)
Temperature coefficient of resistance (TCR) ±300 ppm/°C
Power dissipation 1W at 55°C
Limiting voltage 350V
Operating torque ≤40 mNm
Resistance tolerance ±20% for values up to 470kΩ; ±30% for values above 470kΩ
Climatic category 55/100/56
Available in standard or hermetic (CW18H) version
All terminals are solder tag type; spindle end options P1, P3, and P5 in selectable shaft lengths
What are the CW-18 Series Thick Film Cermet Rotary Potentiometers?
The CW-18 is a thick film cermet rotary potentiometer in an 18.5mm metal housing, built around a layered cermet resistance track deposited on a ceramic base. The combination of cermet resistive technology and ceramic substrate gives the CW-18 substantially better long-term stability and temperature tracking than carbon-film alternatives, making it the component of choice in industrial control applications where the set resistance value must remain consistent over time and across ambient temperature variation. The metal housing serves a dual purpose, providing mechanical protection for the resistive element while its profiled exterior geometry acts as a passive heatsink, dissipating heat away from the resistance track and enabling the 1W power rating to be sustained reliably at an ambient temperature of 55°C.
The actuating mechanism uses an isolated rotor carrying a carbon wiper that traverses the cermet resistance track as the metal spindle is rotated. The electrical isolation of the rotor from the spindle shaft reduces parasitic conduction paths and improves safety in circuits operating at or near the 350V limiting voltage. The three solder-tag terminals follow a standard layout: terminals a and c are the end connections spanning the full resistance track, while terminal b is the central terminal connected to the wiper, enabling both full-track and wiper-to-end resistance configurations. All three terminals are solder tag type, suited to cable attachment and panel-wiring installations rather than direct PCB insertion.
The resistance range covers 100Ω to 2.2MΩ using E6 preferred values in a strictly linear (A) taper characteristic. Resistance tolerance is ±20% as standard for values up to 470kΩ, widening to ±30% for higher values. The temperature coefficient of resistance of ±300 ppm/°C defines the degree of resistance drift per degree of temperature change, a parameter of direct relevance in industrial control loops where the potentiometer’s set value forms part of a calibrated reference or feedback network. The operating torque ceiling of 40 mNm ensures that the spindle can be turned with standard tooling while remaining firm enough to resist vibration-induced drift in installed equipment.
The CW-18 is available in a standard open construction and a hermetic sealed variant (CW18H), the latter providing protection against moisture ingress, dust, and chemically aggressive atmospheres for deployment in particularly harsh or outdoor industrial environments. Spindle end types P1, P3, and P5 are available in selectable standard shaft lengths, accommodating flat, plain cylindrical, and flatted profiles to suit different knob and tool drive requirements. The climatic category of 55/100/56 confirms qualification across a −55°C to +100°C temperature range with humidity endurance testing. Units are supplied in bulk plastic bag and carton box packaging.
CW-18 Series Thick Film Cermet Rotary Potentiometers Specifications
A practical overview for engineers and procurement teams evaluating resistive solutions.
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
Applications of the CW-18 Series Thick Film Cermet Rotary Potentiometers
Where RARA variable resistors are deployed in the field.
Industrial process control equipment — setpoint, reference, and calibration adjustment requiring cermet stability and 1W dissipation
Power supply and voltage regulation circuits — output voltage and current limit setting in industrial and panel-mounted power equipment
Motor drive and variable-speed drive systems — speed reference, torque limit, and acceleration ramp adjustment in industrial drives
Industrial automation and instrumentation panels — analogue signal scaling, bias, and offset adjustment in process control assemblies
High-voltage control circuits — reference divider and level adjustment networks operating at or near the 350V limiting voltage
Harsh and outdoor industrial environments — hermetic variant for moisture, dust, and corrosion-resistant installations
Test and measurement instrumentation — stable calibration and range adjustment in precision industrial and laboratory instruments
Heating, ventilation, and HVAC control systems — temperature setpoint and zone control adjustment
Medical and laboratory equipment — repeatable control adjustment in sensitive measurement and diagnostic instrumentation
General-purpose industrial control panels — rotary adjustment wherever cermet thick film stability, heatsink-profiled housing, and 350V limiting voltage are required
Related Products of the CW-18 Series Thick Film Cermet Rotary Potentiometers
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.
