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How does an induction cooktop work?

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Quick answer

An induction cooktop uses a coil under the glass to create a fast-changing magnetic field. This field induces electric currents inside a magnetic pan, and the pan's resistance turns those currents into heat. The pan heats directly, so the glass stays cooler and the food cooks faster than on many traditional stoves.

An induction cooktop works by generating a rapidly changing magnetic field in a coil beneath the glass, which induces circular electric currents inside the iron or steel base of a compatible pan. Those currents heat the pan directly, and the pan then cooks the food, while the glass stays relatively cool.

Step by step

  1. Electricity flows from the wall into the cooktop's power electronics, which convert it to a high-frequency alternating current.
  2. This current passes through a copper coil located just beneath the ceramic glass surface.
  3. The coil generates a magnetic field that reverses direction thousands of times per second.
  4. When a ferromagnetic pan is placed on the glass, the changing field induces circular eddy currents inside the pan's base.
  5. The pan's electrical resistance converts the eddy currents into heat, which spreads through the metal and cooks the food.

Key things to understand

  1. A coil of copper wire sits just under the ceramic glass surface of the cooktop.
  2. The cooktop's electronics push alternating current through the coil at a high frequency, typically around 20,000 to 50,000 hertz.
  3. This alternating current creates a magnetic field that constantly reverses direction, expanding and collapsing many times per second.
  4. When a pan made of iron or magnetic stainless steel sits on the glass, the changing magnetic field induces swirling electric currents, called eddy currents, inside the pan's base.
  5. The electrical resistance of the pan's metal converts those eddy currents into heat, which spreads through the pan and cooks the food.

Labelled diagram

  1. Power supply

    Wall electricity enters the cooktop and is converted to high-frequency AC.

  2. Induction coil

    A copper coil under the glass carries the alternating current.

  3. Magnetic field

    The coil creates a field that reverses direction many times per second.

  4. Eddy currents

    The field induces swirling electric currents inside the pan's magnetic base.

  5. Heat

    Resistance in the pan converts the currents into heat that cooks the food.

How an induction cooktop heats a pan

Real-world examples

  • A cast-iron skillet on an induction hob heats up in seconds because its iron base responds strongly to the magnetic field.
  • A glass or aluminum pan will not heat on an induction cooktop because the magnetic field passes through without creating significant eddy currents.
  • Professional kitchens in Japan and Europe often use induction ranges for precise temperature control and faster boiling.
  • A magnetic stainless steel pan with a thick base works on induction, while a pure copper pan does not.

Common mistake

✗ Myth: Induction cooktops heat the glass surface, which then heats the pan.

✓ Fact: The glass is not heated directly by the magnetic field; it only warms from contact with the hot pan. The pan itself is the source of heat, which is why the glass stays relatively cool.

People also ask

What is an induction cooktop and how does it work?
An induction cooktop is a stove that uses a magnetic field to heat a compatible pan directly. A coil under the glass creates a rapidly alternating magnetic field, which induces electric currents in the pan's base. Those currents meet resistance and produce heat, cooking the food while the glass stays cooler.
Why does induction cooking require special pans?
Induction relies on a magnetic field to induce currents in the pan. Only pans made of ferromagnetic materials, like cast iron or magnetic stainless steel, allow those currents to form. Pans made of glass, aluminum, or copper do not respond to the field and will not heat.
Is induction cooking better than gas?
Induction offers faster heating, precise temperature control, and higher energy efficiency because heat is generated in the pan itself. Gas provides instant visual flame control and works with any pan shape. The better choice depends on your cookware, kitchen ventilation, and cooking style.
Why does an induction cooktop require special cookware?
Induction needs a pan with a ferromagnetic base, such as cast iron or magnetic stainless steel, so the magnetic field can induce eddy currents in it. Glass, aluminum, copper, and most ceramic pans do not respond to the magnetic field and stay cool. A simple fridge magnet stuck to the pan's base confirms it will work.
Is induction cooking more energy-efficient than gas or electric?
Yes, because the heat is generated directly in the pan rather than in a flame or heating element that also warms the surrounding air. Less energy escapes into the kitchen, so induction transfers a higher share of the electricity into the food. The exact efficiency depends on the pan and the cooktop model.
Can an induction cooktop harm people with pacemakers?
The magnetic field is strongest right above the cooktop surface and drops quickly with distance. Most modern pacemakers are shielded, but health agencies still advise people with implanted medical devices to keep a reasonable distance and consult their doctor. The risk is generally low when normal cooking distance is maintained.
Why does the glass surface of an induction cooktop stay cooler than a traditional electric stove?
The glass itself is not heated by the magnetic field; it only warms up from contact with the hot pan. Since the pan is the heat source, the glass stays relatively cool except directly under the pan. This also means spills are less likely to bake onto the surface.

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