Power Film Resistors

Power film resistors — including thin film, thick film, and aluminum nitride chip variants — are manufactured by depositing a precision resistive layer onto a ceramic or aluminum nitride substrate. This film deposition process achieves tolerances as tight as ±0.1% and TCR values as low as 25 ppm/°C, making them the preferred choice over wirewound resistors when stability under temperature change is critical.

Manufactured under ISO 9001 and IATF 16949 quality systems, RARA power film resistors span from 2W SMD chip resistors to 2000W planar chassis-mount and water-cooled units — covering precision applications in medical equipment, RF and telecom systems, laser power supplies, and industrial inverters. Selected models are laser trimmable post-manufacture for calibration-critical designs.

Compared to wirewound or metal clad resistors, power film designs offer lower inductance, flatter frequency response, and superior resistance stability — advantages that matter in high-frequency and high-accuracy circuits.

High-precision film resistors rated from 10W to 2000W — delivering tight tolerances, low TCR, and high power density in compact chassis-mount, SMD, and water-cooled formats for demanding industrial and high-frequency applications.

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10W – 2000W
Power Range

0.02Ω – 500MΩ
Resistance Range

25 ppm/°C
Best TCR Available

±0.1%
Tightest Tolerance

Certifications: AEC-Q200 l ISO9001 l IATF16949 l UL Listed l Laser Trimmed l TÜV

What is a Power Film Resistor?

A practical overview for engineers and procurement teams evaluating resistive solutions.

A power film resistor is made by depositing a thin or thick layer of resistive material — typically a metal alloy or carbon compound — onto a ceramic or aluminum nitride substrate. Unlike wire wound resistors, the film deposition process is extremely accurate, producing very tight tolerances and low temperature coefficient of resistance (TCR) values that are difficult to achieve with wound construction.

This precision makes power film resistors the preferred choice when accuracy and stability under temperature change are critical — such as in medical equipment, test instrumentation, laser power supplies, and RF/telecom systems. Many RARA models can also be laser trimmed after manufacture for even greater precision, achieving tolerances as tight as ±0.1%.

RARA's power film range spans from compact SMD chip resistors at 2W to massive planar chassis-mount units rated at 2000W, including water-cooled models for the most demanding thermal environments. Aluminum nitride substrate variants offer exceptional thermal conductivity for high-density designs.

Construction

-Thin film on ceramic substrate
-Thick film on ceramic substrate
-Aluminum nitride (AlN) chip
-Carbon film MELF
-Water-cooled planar construction

Key Advantages

-Very tight tolerances — down to ±0.1%
-Low TCR — as low as 25 ppm/°C
-Laser trimmable for extra precision
-High power density in small footprint
-STEP files available for thermal simulation

Power film resistors are the components you want when you need high power with limited space — the film deposition process delivers accuracy that wire wound construction simply cannot match.

Applications

Where RARA power film resistors are deployed in the field.

Medical & Test Equipment

The tight tolerances and stable TCR of film resistors make them essential in medical imaging, laboratory instruments, and precision test equipment — where resistance drift caused by temperature change would affect measurement accuracy.

Telecom & RF Systems

Power film resistors are used as termination resistors, dummy loads, and attenuator components in RF and telecom base stations, where low inductance and flat frequency response are critical. The HPR series supports supply voltages up to 8kV.

Laser Power Supplies

High-power laser systems require stable, accurate load resistors for current control and energy discharge. The HPR planar series at up to 2000W and the RQO capacitor discharge model are purpose-built for pulsed and continuous laser power applications.

Power Supplies & Inverters

Used as snubber resistors, bleed resistors, and feedback network components in switch-mode power supplies, solar inverters, and industrial UPS systems — where low TCR ensures stable regulation across the full operating temperature range.

Water-Cooled Industrial Systems

The WCR water-cooled series (500W–1000W) is designed for high-duty-cycle industrial processes where convection cooling alone is insufficient — including plasma systems, induction heaters, and high-current test rigs.

High-Density PCB Designs

SMD chip variants (SMF, ARN, CRP, TNP) allow engineers to place significant power dissipation capability directly on the PCB — reducing board area requirements in compact power electronics, EV battery management systems, and industrial controllers.

Product Series

Select models from our power film lineup. Download individual datasheets for full specifications, dimensions, and ordering codes.

Power Film Resistors

What is a Power Film Resistor?

Applications

Product Series

Why Choose RARA Power Film Resistors