Induction Heater Working with a Single MOSFET Circuit
Build a single MOSFET induction heater circuit for fast, contactless metal heating. Step-by-step DIY guide with components, working principle, and FAQs included...
What Is a Single MOSFET Induction Heater Circuit?
A single MOSFET induction heater circuit is a state-of-the-art electronic device that provides heat to metals by induction of a high-speed switch (one MOSFET) connected to a resonant circuit of an LC tank. The resonant coil produces an alternating magnetic field that produces eddy currents in the metallic piece of work, ch causes the workpiece to heat.
low cost induction heater with single mosfet
One circuit of a MOSFET induction heater is a simple and efficient method of heating metals without making contact by induction of electromagnetism. The induction heater is best suited to DIY users and small-scale works of metalworking, offering an economical means of heating or softening metal.
The single MOSFET induction heater circuit is a circuit that relies on a high-speed MOSFET that switches DC current through a resonant LC tank, creating strong alternating magnetic fields in the coil. Once a metallic workpiece has been inserted into the coil, eddy currents are generated, creating heat quickly and efficiently. This circuit is simpler to construct, less hazardous at small loads, and uses fewer components than multi-MOSFET or IGBT designs, which makes it ideal not only for the beginner who wants to understand high-frequency electronics, electromagnetic induction, and thermal management, but also because the circuit is simpler to build than more complicated ones.
Advantages of Single MOSFET Induction Heaters
- Simple Design: Uses only one MOSFET and few components.
- Low-Cost DIY Solution: Highly economical for beginners.
- Contactless Heating: Heats metal without physical touch.
- Quick Heating: Ideal for small metal parts and rods.
- Compact Size: Smaller than multi-IGBT induction heaters.
Components Required for DIY Circuit
| Component | Quantity | Purpose |
|---|---|---|
| High-speed MOSFET (IRF540N / IRFZ44N) | 1 | Main switching element |
| Gate Resistor (10–100Ω) | 1 | Limits gate current |
| Flyback / Fast Recovery Diode | 1 | Freewheeling current |
| Capacitors (400V–600V) | 1–2 | Resonant tank circuit |
| Induction Coil | 1 | Generates magnetic field |
| DC Power Supply (12V–24V) | 1 | Powers MOSFET & coil |
| Heat Sink & Fan | 1 | MOSFET cooling |
| Fuse & PCB | 1 | Protection & assembly |
Working Principle of the Circuit
AC Input & Rectification: Low-voltage AC is rectified to DC and smoothed with capacitors.
MOSFET Switching: The MOSFET switches high-speed pulses through the coil.
Resonant Tank: Coil (L) + Capacitor (C) form resonance for efficient heating.
Workpiece Heating: Metal is heated via eddy currents generated in the coil.
Safety: Use heat sinks, fans, and a fuse for protection.
Circuit Diagram Explanation
DC Supply → MOSFET Drain → Coil → MOSFET Source → Ground
Gate → Gate Resistor → Control Signal
Capacitor → Across Coil (Resonant Tank)
Diode → Across MOSFET or Coil
Step-by-Step Construction Guide
- Build Resonant Coil: Make coil and connect capacitor for tuning.
- Connect MOSFET: Gate → resistor; drain → coil; source → ground.
- Power Supply: Connect 12–24V DC supply.
- Cooling: Mount MOSFET on heat sink with a fan.
- Testing: Insert metal in coil, power ON, and observe heating.
Applications
- Soldering and brazing small metal parts
- Heating bolts, screws, and rods
- Small-scale metal annealing
- DIY electromagnetic experiments
- Metal softening for bending
Troubleshooting Tips
| Problem | Cause | Solution |
|---|---|---|
| No heating | MOSFET not switching | Check gate drive & coil wiring |
| MOSFET overheating | Insufficient cooling | Upgrade heat sink/fan |
| Slow heating | Bad LC tuning | Change coil turns/capacitor value |
| Fuse blowing | Overcurrent | Check MOSFET rating & short circuits |
Frequently Asked Questions - Induction Heater Working with a Single MOSFET Circuit:
What is a single MOSFET induction heater?
A circuit that heats metal using electromagnetic induction with one MOSFET switch.
Which MOSFET is suitable?
IRF540N or IRFZ44N high-speed MOSFETs are commonly used.
What metals can be heated?
Small ferrous and conductive metals like copper, aluminum, and steel.
What voltage is required?
Typically 12V–24V DC for small DIY circuits.
Do I need a resonant capacitor?
Yes, to form an LC resonant tank for efficient heating.
Is cooling needed?
Yes, MOSFETs require heatsink and fan for thermal management.
Can it melt metal?
Only small, low-melting-point metal pieces can be melted.
Is it safe for beginners?
Yes, with proper insulation, fuse, and low-voltage DC supply.
How is heating controlled?
By adjusting supply voltage, coil turns, or resonant capacitor value.
Can it be used for soldering?
Yes, suitable for small metal soldering or brazing tasks.
