MOSFET or IGBT?

MOSFET vs IGBT in power electronics: conduction loss, voltage class, switching frequency, applications, replacing them during repair, and common mistakes.

Short answer

At low and medium voltages (roughly under 200 V) and high frequencies, the MOSFET is more efficient. 600 V and above, high current and low-to-medium frequency (welders, induction hobs, VFDs) is IGBT territory.

Comparison

	MOSFET	IGBT
Control	Gate voltage	Gate voltage (usually +15 V to turn on)
Loss when on	Like a resistor: I² × RDS(on)	Like a diode: ≈ I × VCE(sat), a roughly fixed 1.5–2.5 V drop
Typical voltage class	Mostly under 200 V in silicon (up to 1200 V with SiC)	600 – 1700 V and above
Switching frequency	20 – 200 kHz and up	≈5 – 30 kHz; slow turn-off (tail current)
Reverse diode	Has an internal body diode	Most have a separate diode co-packed
Typical use	DC-DC converters, 12–48 V motor drives, SMPS	Welders, induction hobs, VFDs, inverter air conditioners

Choose a MOSFET if…

✓The voltage is roughly under 200 V
✓The switching frequency is high (SMPS, DC-DC)
✓It's a battery system where efficiency matters

Choose an IGBT if…

✓You're working at 600 V or more
✓Current is high and frequency low-to-medium
✓You're repairing a welder, induction hob or motor drive (replace like for like)

Common mistakes

!Swapping an IGBT for a MOSFET (or vice versa) during repair based only on voltage and current. Speed, VCE(sat), gate voltage and package must also match.
!Replacing a blown IGBT without checking the gate driver, gate resistors and snubber. If the real cause is there, the new part blows at first power-up too.
!Trying to drive an IGBT from 5 V. IGBTs usually turn on at +15 V, and some circuits switch them off with a negative voltage.
!Forgetting thermal paste or the insulating pad when mounting on the heatsink.
!Judging the part healthy from the reverse diode alone on a multimeter. Also briefly trigger the gate with a 9 V battery and check it conducts.

Try it: losses as frequency rises

Raise the switching frequency and watch the losses grow, and see why IGBTs stay at lower frequencies.

Open the simulator full page →

🔒 This content is in the repair pack

The repair pack unlocks all interactive content in one go: diagrams and current flows, the Repair Workshop, simulations, concepts, IC guides, the Component Library and comparison guides. One sample in every section is free.

Repair pack: 5,000 ₺, members get 10% off → 4,500 ₺. Or 1-week access for 1,000 ₺.

Learn the topic in depth

More guides

MOSFET or BJT?Zener or regular diode?Electrolytic, ceramic or tantalum?Triac or thyristor (SCR)?Carbon film or metal film resistor?