CTR Series Bulk Ceramic Tubular Resistors
Bulk ceramic sintered resistive element in large-format hollow cylindrical tube form factor
Power rating 15W to 1000W — the highest continuous power rating in the RMS ceramic resistor range
Resistance range 1Ω to 1MΩ
Tolerance options ±5% and ±10%
TCR per datasheet — refer to individual size specifications
Inherently non-inductive construction — energy dissipated uniformly through the entire ceramic body
Available in a wide assortment of diameters and lengths to suit diverse mounting and power requirements
Multiple termination and mounting hardware options available including end-band contacts, push-in brackets, and thru-bolt bracket assemblies
Anti-track coating available on outer and inner diameter surfaces between contact areas
What are the CTR Series Bulk Ceramic Tubular Resistors?
The CTR is a high-power bulk ceramic tubular resistor manufactured by sintering resistive particles within a binding ceramic medium to produce a large-format hollow cylinder. It occupies the top of the RMS ceramic resistor range, with continuous power ratings from 15W at the smallest sizes up to 1000W at the largest, and is designed for applications where neither the rod nor the smaller tube variants of the 83-series can provide sufficient single-component power dissipation. The tubular geometry is particularly effective at this power level: the hollow bore creates a large internal surface area that, combined with the substantial outer surface, gives the CTR a surface-area-to-volume ratio well suited to natural convective cooling in open air, and the ceramic wall thickness provides the resistive mass needed to absorb high-energy transient events without thermal runaway at the element surface.
The CTR shares the fundamental construction principle of all bulk ceramic resistors: the resistive material is distributed uniformly throughout the full thickness and length of the ceramic wall rather than being confined to a film or wound wire. This means there is no surface layer to delaminate and no helical conductor to rupture under overload. Surge and pulse energy is spread across the entire ceramic volume, giving the CTR exceptional tolerance of repetitive high-energy transients. The construction is also inherently non-inductive, since there is no wound wire path through the component; the CTR presents a purely resistive impedance even at high frequencies and switching rates where wirewound alternatives of comparable power rating would introduce significant inductive reactance. Resistance values span 1Ω to 1MΩ with tolerance options of ±5% and ±10%, covering the impedance requirements of a broad range of industrial load, snubber, damping, and protection circuits within a single product series.
The CTR is available in a wide assortment of tube diameters and lengths, allowing the designer to select the geometry that best matches the power rating, energy absorption capacity, voltage rating, and physical envelope of the target application. Electrical connection is made through metalised end-band contacts at each end of the tube body, and a variety of terminal and mounting hardware configurations is available including push-in spring brackets and thru-bolt bracket assemblies with associated hardware, enabling the CTR to be panel-mounted, chassis-mounted, or installed in open-frame rack assemblies. An anti-track coating is available on both the outer diameter and inner bore surfaces between the contact bands, extending the component’s operating voltage margin in high-voltage, humid, or contaminated service environments. Multiple CTR tubes can be connected in series or parallel arrangements to achieve resistance values or power ratings beyond those of a single standard-size component.
CTR Series Bulk Ceramic Tubular Resistors Specifications
A practical overview for engineers and procurement teams evaluating resistive solutions.
Model: CTR
Resistor type: Bulk Ceramic
Description: Tubular Resistors
Power Rating: 15W~1000W
Resistance (Ω): 1~1M
Tolerance (%): ±5, ±10
TCR (ppm/C): See More Information
Applications of the CTR Series Bulk Ceramic Tubular Resistors
Where RARA ceramic resistors are deployed in the field.
High-power load resistors and dummy loads — single-component continuous dissipation up to 1000W without localised element failure, suitable for generator, UPS, turbine, and battery system load bank testing
Dynamic braking resistors for AC and DC motor drives — non-inductive ceramic construction absorbs kinetic energy returned from the motor during deceleration without introducing inductive transients on the drive bus
Snubber and damping circuits in high-power inverters and converters — purely resistive impedance at switching frequencies prevents oscillation and voltage overshoot without the frequency-dependent behaviour of wirewound alternatives
RF power amplifier loads and transmitter dummy loads — inherently non-inductive bulk ceramic body maintains consistent resistive termination across a wide frequency range in transmitter, modulator, and RF test applications
Impulse voltage generators and high-voltage pulse discharge circuits — volumetric energy absorption across the full ceramic wall handles high-energy single-shot and repetitive pulse duties at voltages up to 1MΩ range
High-voltage power supplies, X-ray equipment, and industrial power conditioning — wide resistance range to 1MΩ and anti-track coating option support operation in kilovolt-level environments
Inrush current limiting for large motor drives, capacitor bank pre-charge, and soft-start systems — high power rating accommodates the sustained dissipation requirements of large-scale industrial inrush events
Surge and transient energy absorption in electrical transmission and distribution equipment — bulk ceramic wall absorbs fault-level pulse energies across the entire tube cross-section without surface film delamination or wire burn-out
Series and parallel CTR assemblies for custom load banks and test systems — tubes may be combined in bracket-mounted multi-tube arrays to achieve total power ratings or resistance values not available in a single component
Industrial test and measurement equipment — stable, non-inductive high-power reference loads for acceptance testing, calibration, and power quality measurement of large generators, UPS systems, and industrial drives
Related Products of the CTR Series Bulk Ceramic Tubular Resistors
Model: 83-A
Resistor type: Bulk Ceramic
Description: Axial lead rods
Power Rating: 2.2W~7W
Resistance (Ω): 6~977k
Tolerance (%): ±5, ±10, ±20
TCR (ppm/C): -500~-1500
Model: 83-T
Resistor type: Bulk Ceramic
Description: Tubes
Power Rating: 12W~352W
Resistance (Ω): 1~295k
Tolerance (%): ±5, ±10, ±20
TCR (ppm/C): -500~-1500
Model: 83-R
Resistor type: Bulk Ceramic
Description: Rods
Power Rating: 4.7W~445W
Resistance (Ω): 0.9~244k
Tolerance (%): ±5, ±10, ±20
TCR (ppm/C): -500~-1500
Model: 83-W
Resistor type: Bulk Ceramic
Description: Organic, washers
Power Rating: 3.8W~327W
Resistance (Ω): 20m~6.8k
Tolerance (%): ±5, ±10, ±20
TCR (ppm/C): -500~-1500
Why Choose RARA Ceramic Resistors
What sets RARA apart for engineers and procurement managers in industrial and automotive markets.
01
Unique Negative TCR
The -500 to -1500 ppm/°C negative TCR is a fundamental property of sintered bulk ceramic — exploited in inrush limiting, soft-start, and temperature compensation circuits where resistance must decrease with temperature rise.
02
Surge Tolerant by Design
The bulk distributed construction absorbs pulse and surge energy throughout the entire volume of the component — giving ceramic resistors exceptional pulse handling capability compared to surface-film types of equivalent power rating.
03
Five Form Factors
Axial rods, bare tubes, bare rods, washers, and disks — five geometries covering through-hole PCB, chassis, in-line bus bar, and panel mounting requirements in a single product family.
04
Global Track Record
Trusted by Siemens, Rockwell, Schneider Electric, and Hanwha — deployed in industrial power electronics, inrush protection, and surge limiting applications across six continents.
