In the realm of DIY electronics, few projects are as exciting and visually impressive as an induction heater. Watching a piece of metal glow red hot without touching it or exposing it to an open flame is nothing short of fascinating. And at the heart of such a project lies a powerful and reliable IGBT transistor. One particular component that fits the bill is the STGW60H65DFB, a high-speed, high-voltage Insulated Gate Bipolar Transistor made by STMicroelectronics. This article explores a specific DIY project: constructing a compact but powerful induction heater based around the STGW60H65DFB, without diving into any coding, formulas, or complex schematics—just a clear, hands-on explanation of how the project unfolds.

Understanding the Project Vision

This project is aimed at electronics hobbyists who are keen to work with high-voltage and high-power components. The idea is to build a table-top induction heating unit that can heat metal objects like bolts, small steel rods, and other ferrous materials quickly and efficiently. Unlike soldering stations or open flame heating, induction heating is clean, safe (when handled properly), and highly efficient.
Using the STGW60H65DFB as the key switching element, this induction heater will be capable of handling substantial power levels with greater stability and reduced heat loss, making it an ideal component for this build.

Getting to Know the STGW60H65DFB

Before diving into the actual project build, it's worth understanding the component that will serve as the core of our device. The STGW60H65DFB is a high-voltage, high-current IGBT (Insulated Gate Bipolar Transistor) capable of operating at voltages up to 650V and handling continuous currents up to 120A in pulsed mode. It’s designed for fast switching, which is critical for induction heating where rapid transitions help create the alternating magnetic field needed to generate heat in the workpiece.
The TO-247 package of this transistor also provides excellent thermal performance, which is essential since the device will be operating under significant stress in a heating application.

Project Overview

The goal is to construct a desktop induction heater powered by a 36V DC power supply, capable of heating small metallic items in seconds. The key sections of this project include:

1. Power Supply
2. Oscillator Circuit
3. Resonant Tank Circuit
4. Cooling System
5. Enclosure and Safety Features

Step 1: Sourcing the Components

Apart from the STGW60H65DFB IGBT, the project requires several other components and materials:
●  A 36V, 20A DC power supply
●  High-current capacitors (for resonance tank)
●  Copper tubing for the induction coil
●  Ferrite core (optional but improves performance)
●  Fast recovery diodes
●  Heat sinks and cooling fans
●  Gate driver circuit (opto-isolated for protection)
●  Control switch with indicator light
●  Thermal paste and insulation material
Many of these can be found from electronics suppliers or salvaged from old power electronics equipment. The copper tubing used for the heating coil can often be found in refrigeration repair shops or HVAC suppliers.

Step 2: Constructing the Resonant Tank Circuit

The resonant tank circuit is where the magic happens. It consists of a high-frequency coil (our copper tubing) and a capacitor bank connected in parallel or series-parallel, forming an LC resonant circuit. When energized, this circuit creates an oscillating magnetic field.
The STGW60H65DFB IGBT is used to switch this circuit on and off at high speed, inducing a rapidly changing magnetic field in the coil. When a metal object is placed within the coil, it experiences eddy currents and heats up due to its internal resistance.
The coil should be shaped into a tight spiral, large enough to accommodate small bolts or tools. Proper spacing between the turns is important to avoid arcing.

Step 3: Assembling the Driver Circuit

To control the IGBT, a gate driver is required. This module takes the low-voltage control signal and boosts it to the level needed to switch the IGBT effectively. For safety and reliability, it's best to use an opto-isolated gate driver module. This isolates the control circuitry from the high-power side, preventing any dangerous feedback.
In this setup, the driver receives power from a separate 12V source and is triggered via a simple toggle switch on the front panel. Once activated, it drives the IGBT at high frequency, which in turn energizes the coil.
The STGW60H65DFB must be mounted on a proper heat sink with thermal paste to ensure good thermal conductivity. Active cooling via a small fan is strongly recommended, as the device will heat up during prolonged operation.

Step 4: Power Distribution and Safety

Working with high-current DC circuits demands careful attention to wiring and safety. All connections to the IGBT and resonant circuit should use thick, low-resistance wire to avoid voltage drops and excessive heat.
A main power switch with a light indicator is mounted on the enclosure. Additionally, fuses or circuit breakers are highly recommended to protect against overcurrent conditions. A thermal cutoff switch mounted on the IGBT’s heat sink can provide an extra layer of safety by disabling the circuit if the transistor gets too hot.

Step 5: Enclosure and Cooling

Once the circuitry is tested and working reliably on a bench setup, it’s time to build a suitable enclosure. A metal or thick plastic case can be used, but it must have proper ventilation. Fans should be installed to draw heat away from the heat sinks and out through vent holes.
Position the coil outside or at the front of the enclosure, mounted securely so it doesn’t shift during use. Users should be instructed not to touch the coil while the unit is in operation, as it gets extremely hot. A mesh guard or a plexiglass shield can be added for additional safety.

Step 6: Testing and Calibration

With everything in place, the induction heater is ready for testing. Start by powering the system without a workpiece to ensure that all components are functioning and staying cool. Once you're confident in the setup, introduce a small steel object into the coil and activate the circuit.
You should see the object begin to heat up within seconds. If the object doesn’t heat up, check your connections, especially in the resonant tank circuit and the gate driver. Minor adjustments to coil shape or capacitor values may help optimize performance.
Observe the IGBT’s heat sink during prolonged operation. If it becomes excessively hot, increase fan speed or upgrade the heat sink.

Applications of the Induction Heater

Once completed, your DIY induction heater can be used for a wide variety of tasks:
●  Heat treating metal tools to harden or temper them.
●  Removing seized bolts by heating them to expand and loosen the threads.
●  Melting small quantities of metal like solder or aluminum (with precautions).
●  Scientific demonstrations for educational use.
It's important to never use the induction heater on unknown metal types, as some materials may spark or cause arcing. Always use protective gear like gloves and goggles when operating the device.

Lessons Learned and Tips

Working with the STGW60H65DFB revealed just how crucial good thermal management and switching efficiency are in high-power electronics. Unlike simpler transistors or MOSFETs, IGBTs can handle much more power but must be carefully driven to avoid failures.
Here are a few tips for those planning to take on this project:
●  Use a proper gate resistor between the driver and IGBT to prevent voltage spikes.
●  Don’t underestimate the heat: even short sessions can cause significant temperature rise.
●  Double-check polarity and connection orientation before applying power.
●  Use shrink tubing and insulation wherever there’s a risk of shorts.

Final Thoughts

This induction heater project isn’t just a fun DIY activity—it’s a hands-on introduction to the power and utility of modern electronic components like the STGW60H65DFB. Watching cold steel glow orange-red in seconds brings a unique satisfaction, and doing it with a circuit you built yourself is even better.
Beyond the technical knowledge, such projects also teach patience, discipline, and safety—vital traits for any serious electronics enthusiast. And while this heater may be compact, it’s a strong reminder of what’s possible when high-performance components meet careful planning and hands-on creativity.
In the end, the STGW60H65DFB doesn’t just act as a switch. In this project, it serves as the beating heart of a powerful DIY tool—quietly but confidently transforming volts and amps into controlled electromagnetic fury.