Why Are We Still Using Through-Hole (THT) Components in 2026?

It's 2026, Why Are We Still Using Through-Hole (THT) Components? 4 Hardcore Advantages of THT

Tear down any modern smartphone or high-end GPU, and you'll be greeted by a sea of microscopic 0201 or even 01005 Surface Mount Technology (SMT) components. In today's relentless pursuit of extreme miniaturization and high-frequency signal integrity, SMT is the undisputed king.

This dominance often leads junior PCB designers to a common misconception: "Through-Hole Technology (THT) is an ancient relic. Premium boards should be 100% SMD."

But step just slightly off the consumer electronics path into industrial control, high-power supplies, or automotive electronics, and you'll find THT holding its ground as firmly as ever. A highly upvoted comment in the famous r/AskElectronics community sums it up perfectly: "Give me a TO-220 package, some thermal paste, and an M3 bolt, and I'll use it any day."

So, here in 2026, what makes veteran engineers still reach for THT when laying out a board?

1. Table of Contents
2. 1. Brute-Force Mechanical Strength: The Last Line of Defense
3. 2. High Power & Extreme Thermals: Breaking Free from Copper Pours
4. 3. Field Repairability 30 Years Down the Line
5. 4. The Cradle of Prototyping and Maker Culture
6. The Engineer's Dilemma: SMT vs. THT from a DFM Perspective
7. FAQ: Top THT Concerns from the Engineering Community

Before we dive deep, let's look at a quick baseline comparison of the physical and electrical realities of SMT vs. THT:

Table 1: SMT vs. THT - Core Characteristics & Use Cases

1. Brute-Force Mechanical Strength: The Last Line of Defense

This is the physical gap SMT can never bridge. SMT components simply "sit" on the surface. Their resistance to mechanical stress relies entirely on the adhesion of a microscopic layer of copper foil and solder paste.

In the real world, PCBs are subjected to serious physical abuse:

• High-cycle connectors: Think high-current power jacks, industrial D-Sub connectors, or audio jacks on guitar pedals. If you use pure SMT here, the mechanical leverage of plugging and unplugging will inevitably cause catastrophic pad lifting.
• Heavy components: Massive electrolytic capacitors, common-mode chokes, and transformers carry significant mass. In environments with high-frequency vibrations (like automotive or robotic arms), the fatigue on an SMT joint supporting a heavy component will quickly lead to cracked solder joints.

THT leads pass all the way through the board, anchored by a solid plug of solder formed during wave soldering. This "rooted" structure provides unmatched mechanical strength against shear and pull forces.

2. High Power & Extreme Thermals: Breaking Free from Copper Pours

Handling serious current is THT’s traditional stronghold. When dealing with high-wattage dissipation, your thermal path dictates whether your product lives or goes up in smoke.

For SMT power devices, heat must be pushed down through thermal vias into large, internal copper planes. This eats up incredibly valuable routing space and is fundamentally bottlenecked by the thermal resistance of the FR-4 substrate itself.

In contrast, classic THT packages (like TO-247 or TO-220) feature a dedicated metal mounting tab. Engineers can bolt them directly to massive extruded aluminum heatsinks—or even use the product's metal enclosure as a heatsink—paired with active airflow. This direct-to-ambient thermal transfer is something micro SMDs simply cannot replicate.

3. Field Repairability 30 Years Down the Line

Consumer tech is designed for a 2 to 3-year lifecycle—if it breaks, you chuck it. But industrial variable frequency drives, medical monitors, or grid protection relays are expected to operate for 20 to 30+ years.

When a machine goes down in a remote mine or a dusty factory floor:

• The SMT Nightmare: A field technician without a hot air rework station and microscope has a near-zero chance of replacing a blown QFN or BGA chip. Worse, high-density SMT chips go obsolete quickly, making replacement parts impossible to find.
• The THT Savior: A basic $20 soldering iron is all it takes to swap out a burnt through-hole relay in minutes. Furthermore, THT footprints are remarkably standardized and timeless. Of course, if your legacy equipment truly hits an End-of-Life (EOL) component wall, partnering with a platform that has a global procurement network and a robust Turnkey BOM Service is the safest way to bring legacy boards back to life.

4. The Cradle of Prototyping and Maker Culture

In the early Proof-of-Concept (PoC) stages, THT is still the king of rapid iteration.

• Breadboarding: You don’t need to wait for a board spin. THT parts drop right into a breadboard to test logic instantly.
• Modern Prototyping: That said, breadboards suffer from massive parasitic capacitance. Today, serious engineers skip the perf-board wire-wrapping. Thanks to rapid modern manufacturing, using a dedicated Rev0 Prototype PCBA service gets you a real mixed-technology board in days, which is vastly cleaner and more reliable than a rat's nest of jumper wires.

The Engineer's Dilemma: SMT vs. THT from a DFM Perspective

If THT is so robust, why not use it everywhere? Because when it comes to Signal Integrity (SI) and mass production costs, THT hits a hard ceiling.

When evaluating Design for Manufacturability (DFM) or dropping files to a contract manufacturer, engineers must navigate the hidden costs of "Mixed Technology" assembly:

Table 2: DFM Cost Analysis for Mixed SMT/THT Technology

The Ultimate Compromise: Pin-in-Paste (PiP)

If you need the mechanical strength of THT but refuse to pay for a secondary wave soldering step, modern manufacturing offers an elegant solution: Pin-in-Paste (PiP) / Through-Hole Reflow (THR). By using high-temp rated THT components, solder paste is printed directly into the plated through-holes, and the THT part goes through the standard SMT reflow oven alongside everything else.

However, this requires extreme precision in stencil step-down design and solder volume calculation. This makes auditing your manufacturer's PCB Assembly Capabilities critical. Whether your layout is a high-density HDI design or a rugged mixed-tech power board, partnering with elite PCB Assembly Services (Gia công PCBA) can help you avoid nasty manufacturing traps before you even finalize your Gerber files.

FAQ: Top THT Concerns from the Engineering Community

Q1: Everyone is pushing SMT. Will THT parts go completely obsolete and become impossible to buy in the next 10 years?

A: Absolutely not. While digital logic ICs abandoned DIP packages long ago, the demand for THT in power electronics (capacitors, MOSFETs, relays) and electromechanical parts (switches, connectors) is massive. The industrial, military, and automotive supply chains rely on them. The "THT is dying" narrative is mostly baseless fear-mongering.

Q2: My design is 98% SMT, with just two through-hole pin headers. Will the factory charge me massive wave soldering fees for this?

A: Generally, no. For extremely low THT part counts, a reputable contract manufacturer won't run it through a wave machine. They will use Selective Wave Soldering or simply have skilled technicians hand solder them post-reflow. During the DFM review, you can negotiate the most cost-effective routing with your CM.

Q3: I'm a hobbyist and I hate the idea of learning SMT soldering. Is it bad to stick purely to THT?

A: If you are building low-frequency analog circuits (like audio synthesizers or guitar pedals), THT is perfectly fine. But if you want to play with modern MCUs (like an ESP32) or high-speed sensors, SMT is unavoidable. Honestly, with a cheap hotplate or a hot air gun, SMT soldering is actually faster and cleaner than clipping leads on 50 through-hole resistors. Don't let the small size intimidate you!

The Bottom Line: Right Tool for the Right Job

SMT and THT are not enemies; they are complementary tools in an engineer's arsenal. The most mature commercial designs follow a simple rule: "Let SMT handle the brains, logic, and high-speed routing, while THT does the heavy lifting for power delivery, interfaces, and structural integrity."

If you've just finished routing a mixed-technology board and are looking for a reliable partner for prototyping or mass production, NextPCB offers highly automated SMT lines paired with veteran selective/manual soldering teams. Simply upload your Gerbers and BOM to get a transparent, instant Online PCBA Quote (Sebut Harga PCBA), and let's get your hardcore hardware built right the first time.

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About the Author

Stacy Lu

With extensive experience in the PCB and PCBA industry, Stacy has established herself as a professional and dedicated Key Account Manager with an outstanding reputation. She excels at deeply understanding client needs, delivering effective and high-quality communication. Renowned for her meticulousness and reliability, Stacy is skilled at resolving client issues and fully supporting their business objectives.

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