Bulk ceramic resistors manufactured by sintering resistive particles in a binding medium — available as axial rods, tubes, rods, washers, and disks from 2.2W to 445W, with a characteristic negative TCR that makes them uniquely suited to surge limiting and inrush protection applications.
-500 to -1500 ppm/°C
Negative TCR
20mΩ – 235MΩ
Resistance Range
Rod, Tube etc.
Technologies
Technologies:
Negative TCR
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Sintered Construction
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Surge Tolerant
What Is a Ceramic Resistor?
A practical overview for engineers and procurement teams evaluating resistive solutions.
A
bulk ceramic resistor
is fundamentally different from wire wound, film, or carbon resistors. Rather than depositing a resistive element onto a substrate, bulk ceramic resistors are made by
sintering resistive particles in a binding medium
— compressing and firing a mixture of conductive and insulating materials into a solid ceramic body. The result is a resistor whose resistive material is distributed uniformly throughout the entire bulk of the component, not just on the surface.
This construction gives bulk ceramic resistors a distinctive and useful property: a
negative temperature coefficient of resistance (negative TCR)
of -500 to -1500 ppm/°C. This means resistance decreases as the component heats up — the opposite of wire wound and film types. In surge and inrush applications, this behaviour is highly desirable: as current flows and the resistor warms, its resistance drops, allowing the circuit to stabilize naturally as the surge event subsides.
RARA's 83-series bulk ceramic resistors are available in five physical forms —
axial lead rods (83-A), tubes (83-T), rods (83-R), organic washers (83-W), and organic disks (83-D)
— spanning power ratings from 2.2W to 445W and resistance values from 20mΩ to 235MΩ. The variety of form factors allows designers to select the geometry best suited to their mounting and thermal management approach.
Construction Technologies
-83-A — Axial lead rods (leaded)
-83-T — Tubes (bare)
-83-R — Rods (bare)
-83-W — Organic washers
-83-D — Organic disks
Key Advantages
-Negative TCR: -500 to -1500 ppm/°C
-Resistance decreases as temperature rises
-Excellent surge and pulse energy tolerance
-Wide resistance range: 20mΩ to 235MΩ
-High power handling in compact form
RARA ceramic resistors are manufactured by sintering resistive particles in a binding medium — available in cylinders, tubes, washers, and disks for a wide variety of mounting configurations.
Where RARA ceramic resistors are deployed in the field.
Inrush Current Limiting
The negative TCR of bulk ceramic resistors makes them a natural fit for inrush limiting in power supplies, motor drives, and capacitor bank pre-charge circuits. At startup, resistance is high — limiting the inrush spike. As the component warms during normal operation, resistance falls, reducing steady-state power dissipation automatically without any active control circuit.
Surge & Pulse Energy Absorption
The distributed bulk construction of sintered ceramic resistors allows them to absorb high-energy pulses and surge events across the entire volume of the component — unlike film or wire wound types where surge energy is concentrated at the surface. The 83-T tube and 83-R rod series handle up to 352W and 445W respectively for demanding pulse applications.
Discharge & Bleeder Resistors
Bulk ceramic resistors are widely used as bleeder and discharge resistors in high-voltage power supplies, capacitor bank discharge circuits, and defibrillator charge management — where the combination of high resistance values (up to 235MΩ in the 83-D disk series) and surge tolerance is required in a single component.
Industrial Heating & Temperature Compensation
The negative TCR characteristic can be exploited in temperature compensation networks — pairing a ceramic resistor with positive-TCR components to create circuits whose overall resistance is stable or varies in a controlled manner with temperature. Used in industrial sensors, bridge circuits, and process control instrumentation.
RF & High-Frequency Loads
Ceramic tube and rod resistors (83-T, 83-R) are used as dummy loads and termination resistors in RF test equipment and transmitter systems — where the non-inductive bulk ceramic construction avoids the frequency-dependent behaviour of wire wound types at higher frequencies.
Soft-Start & Power-On Circuits
Washer-format ceramic resistors (83-W) are physically mounted in line with power connections in some soft-start designs — their compact washer geometry allowing direct in-line installation on bus bars or power terminals. As the system warms to operating temperature, resistance drops and the voltage drop across the component becomes negligible.
Select models from our ceramic lineup. Download individual datasheets for full specifications, dimensions, and ordering codes.
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
Model: 83-D
Resistor type: Bulk Ceramic
Description: Organic disks
Power Rating: 18W~180W
Resistance (Ω): 2m~235M
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.
