TO220 Thick Film Power Resistor

The TO220 Thick Film Power Resistor from RST Electric bridges the gap between traditional through-hole power resistors and advanced surface-mount devices, offering the thermal performance of a heatsink-mountable component in a familiar TO220 footprint. This Heatsink Mount Resistor is designed for applications where board space is at a premium but power dissipation requirements exceed what SMD components can handle. The TO220 package allows for single-screw installation directly onto a chassis or heatsink, utilizing thermal interface materials to efficiently transfer heat away from the resistive element.

Internal structure

The internal construction of this Power Thick Film Resistor consists of a high-stability resistive layer deposited on an alumina substrate, which is then wire-bonded to the lead frame and encapsulated in a molded plastic package. This construction provides excellent insulation properties, withstanding voltages up to 1800VAC and maintaining insulation resistance greater than 10GΩ. The non-inductive nature of thick film technology ensures minimal parasitic inductance, making the PRT series suitable for high-frequency switching circuits where wirewound resistors would introduce unacceptable phase shift.

Power rating

The PRT series is available in two power ratings:

● PRT35 – 35W at 25°C case temperature (2.5W without heatsink)

● PRT50 – 50W at 25°C case temperature (3W without heatsink)

Resistance values span from 0.1Ω to 1MΩ, with TCR options ranging from ±50 ppm/°C (for precision values above 10Ω) to ±300 ppm/°C (for low ohmic or high-resistance ranges). Standard tolerances include ±0.5%, ±1%, ±5%, and ±10%, accommodating both high-accuracy instrumentation and general-purpose power applications. As a trusted To220 Thick Film Power Resistor manufacturer in China, RST Electric combines over 10 years of thick film engineering expertise with precision manufacturing to deliver components that provide reliable, stable performance in demanding power electronic circuits.

Technical Specification

TCR by Resistance Range

Electrical Performance

● Lead wire materials: Tinned Copper

● Max torque: 0.9Nm

● Power limit depends on surface temperature of package.

● Temperature measurement required to measure the central of heat sink plate.

● Heat dissipating cream must be applied correctly

What are the core advantages of To220 Thick Film Power Resistor?

1.TO220 Standard Package – Industry-standard footprint with single-screw mounting simplifies mechanical integration and thermal management.

2.High Power Density – 35W (PRT35) or 50W (PRT50) at 25°C case temperature, enabling compact power stage designs.

3.Wide Resistance Range – From 0.1Ω to 1MΩ in a single series, covering applications from current sensing to high-impedance voltage division.

4.Excellent Insulation – Withstands 1800VAC dielectric strength with insulation resistance >10GΩ, ensuring safety in high-voltage circuits.

5.Non-Inductive Construction – Thick film technology minimizes parasitic inductance, ideal for high-frequency switching applications.

6.Precision Tolerances – Available in ±0.5%, ±1%, ±5%, and ±10% to meet both high-accuracy and general-purpose requirements.

7.Low TCR Options – As low as ±50 ppm/°C for precision values >10Ω, ensuring stable performance across temperature variations.

8.Easy Assembly – Single M3 screw mounting with 0.9 Nm maximum torque; leads are tinned for reliable solder connections.

9.Versatile Applications – Suitable for switching power supplies, snubber circuits, power amplifiers, voltage regulation, and pulse loading.

10.Rugged Construction – Molded plastic case protects the resistive element from mechanical stress and environmental contaminants.

Product Applications

Drawing and dimensions

Packaging and Transportation Instructions

Our company strictly controls every transportation step to ensure that the To220 Thick Film Power Resistor arrives safely.

For bulk transportation, anti-static tubes or pallets are used for packaging. Each resistor is independently sealed in an anti-static bag, accompanied by foam cushioning, which effectively prevents pin bending and component damage; additional foam is fixed at the pin end to avoid bumps during transportation. Customized packaging services are also provided, allowing for adjustments of packaging specifications according to purchasing requirements.

Before each resistor leaves the factory, it undergoes 100% electrical testing. Only those that pass the test are packaged. The shipping includes a packing list, inspection report, and other complete materials. The shipping method is flexible. Small batch orders are transported by international courier services such as DHL or FedEx, medium batch orders by air freight, and large batch orders by sea freight, balancing efficiency and cost. Storage should be in a well-ventilated and dry environment, away from corrosive substances, to avoid affecting product performance.

Factory Direct Supply Advantage

As a manufacturer specializing in the research and production of To220 Thick Film Power Resistors, we have over 10 years of industry experience, achieving full-process self-control from alloy selection, thick film deposition to product inspection, without any intermediate steps. The factory direct supply model eliminates the premium charged by middlemen, allowing buyers to obtain high-quality products at more favorable prices. At the same time, we can provide customized production according to requirements, precisely matching the actual usage scenarios for resistance value, power, and pin specifications.

We have a complete production system and have obtained ISO 9001 quality certification. Each product undergoes strict testing and meets automotive and industrial usage standards. We also have a professional engineering team that can provide technical support and solution optimization, helping buyers efficiently complete product integration.

FAQ

1.Question: How effective is the packaging protection?

Answer: We use anti-static packaging and foam cushioning. For bulk transportation, we use special cartons. There are additional fixations at the pins, which can effectively prevent bumps and damages during transportation. At the same time, an inspection report is provided with the goods to ensure the integrity of the products.

2. Question: What scenarios can the To220 Thick Film Power Resistor be applied to?

Answer: It is mainly suitable for scenarios such as power supply, industrial control, and automotive electronics. It supports full-dimensional customization, including power, resistance value, pin specifications, terminal type, etc. It can be adjusted according to actual needs to meet different usage scenarios.

3. Question: Is the product quality guaranteed?

Answer: The product has undergone strict testing and meets the automotive-level reliability standards. It comes with a 12-month warranty. It also offers remote fault diagnosis and spare parts replenishment services. A complete test report and qualification documents are provided with the product, ensuring a worry-free purchase throughout the process.

4. Question: How long is the delivery cycle?

Answer: We offer factory direct supply, allowing for flexible adjustment of the production cycle. For standard models, the delivery time is 10-15 working days. For customized models, it is 15-25 working days. The delivery time can be adjusted according to the purchasing requirements, and technical support is also provided.