How Does an Induction Cooktop Work? A Simple Guide

An induction cooktop works by using a coil under the glass plate to create a changing magnetic field. When you place a magnetic metal vessel on the plate, the field makes electric currents flow inside the base of the vessel, and those currents heat it. The heat is made in the vessel itself, not in the cooktop, which is why induction is fast and the plate stays cooler than a gas flame.

This guide explains how an induction stove works step by step, what is inside it, why only some vessels work, how it compares with gas and other cooktops, and what to do if your vessel is not induction friendly.

What is induction cooking?

Induction cooking is a way of heating food with a magnetic field instead of a flame or a hot coil. There is no burning fuel and no red-hot element. The cooktop sends energy through the glass plate straight into a magnetic vessel, so the vessel becomes the heat source.

In India most people call the appliance an induction stove, induction cooker or induction cooktop. In some countries, the word induction hob is used. An induction range is a full kitchen range with induction burners on top and an oven below. Most Indian homes use a single or double portable induction cooktop instead, which needs no installation.

How does an induction stove work, step by step?

•       Electricity flows into a copper coil. Under the glass plate sits a flat coil of copper wire. When you switch the cooktop on, mains power is turned into a fast alternating current, usually tens of thousands of cycles per second, and sent to the coil.

•       The coil makes a magnetic field. The alternating current creates a magnetic field that rises, falls and reverses direction very quickly. The field passes through the glass plate without heating it.

•       The field reaches the vessel. If a magnetic metal vessel such as steel or cast iron is on the plate, the field passes into its base.

•       Currents flow in the base. The changing field makes small swirling electric currents, called eddy currents, flow inside the metal of the base.

•       The metal resists, and heat is made. The metal resists those currents, and that resistance turns them into heat. In magnetic metals like iron, the quick flipping of the magnetic field adds a little more heat.

•       The vessel heats your food. The heat spreads through the base and into the food. When you lift the vessel, the field has nothing to work on, and heating stops.

This is why the plate itself does not become the heat source. It only warms because the hot vessel sits on it.

What is inside an induction cooktop?

Our Chefspecial Induction Cooktop 1600W has all of these. It has a vessel sensor that detects incompatible cookware, a high-rated IGBT that handles voltage fluctuations, eight power levels and a 0 to 3 hour timer. Together these mean it heats only when the right vessel is on the plate and keeps working through voltage fluctuations. It is priced at ₹3,299 and has a 1-year warranty.

How does the cooktop control the heat?

When you lower the power level, the cooktop does not weaken the field the way you turn down a gas flame. It controls how much energy goes in, often by switching the power on and off in short bursts, or by changing how strongly it drives the coil. The vessel responds almost at once, because the heat is made inside the base. That is why induction feels so quick to turn up and turn down.

You may hear a faint click at low levels as the power cycles on and off. This is normal.

Why do only some vessels work on induction?

The magnetic field needs a metal it can work with. Magnetic metals such as iron and many types of steel heat very well. Non-magnetic or highly conductive metals, such as aluminium and copper, do not respond enough, and glass and clay do not respond at all.

A simple test is to hold a magnet to the base of the vessel. If it sticks firmly, the vessel will work. The base should also be flat and large enough to cover a good part of the plate, so the vessel sits close to the coil.

Can you use non-induction cookware on an induction cooktop?

Often you can, with an adapter, but we do not suggest it as an everyday habit. An induction interface plate, or adapter disc, is a flat steel disc that you place between the cooktop and a non-induction vessel. The disc heats up from the magnetic field and passes the heat to the vessel.

•       It is slower and wastes energy. Small air gaps between the disc and the vessel slow the heat transfer, so more heat is lost. A disc setup uses noticeably more energy than an induction-friendly pot to do the same job.

•       It can overheat. Heat builds up in the disc and the cooktop, and that can stress the electronics. Use low or medium power and never leave it unattended.

•       It may not be detected. Cooktops with a vessel sensor, like ours, may not recognise an adapter.

Check your cooktop's manual before you try one. The better fix is to buy a few induction-friendly vessels, such as a steel kadhai, a flat tawa and an induction-base pressure cooker. If you want to keep a favourite aluminium or copper vessel, keep using it on your gas stove.

How to use an induction cooktop: the basics

Once you know how it works, using it is simple. Place the cooktop on a flat, dry surface and plug it into a wall socket. Put a magnetic-base vessel with food or water in the centre of the plate, switch on, and pick a power level or a preset. Start low if you are new, and when you finish, let the fan stop before you unplug. For tips on cookware, first-time use and fixes, see our step-by-step guide on how to use an induction cooktop.

Induction vs gas, electric coil and infrared

In plain terms, induction sends most of its energy into the vessel, so less is lost to the kitchen air than with an electric coil or a gas flame.

You can see our range on the induction cooktop.

Benefits of induction cooking

•       Fast. Water can come to a boil faster than on a gas flame.

•       Precise. Power levels respond at once, so you can simmer gently or fry hard.

•       Efficient. Less heat is wasted, so the kitchen stays cooler in summer.

•       Safer than a flame. No gas, no open fire, and heating stops when you lift the vessel.

•       Easy to clean. A smooth plate wipes down in seconds, and spills do not burn on as much.

•       Compact. A portable cooktop suits small kitchens, hostels and as a second burner.

Things to keep in mind

•       It needs induction-friendly vessels.

•       It needs a steady power supply, and a power cut stops cooking.

•       You cannot roast a phulka or papad directly over a flame.

•       Use a flat tawa for dosa and chapati.

•       People with a pacemaker should check with their doctor before using induction.

FAQs

Q: Does an induction cooktop use a flame or a heating coil?

A: Neither. It has a copper coil that creates a magnetic field, but the coil itself does not make heat for cooking. The vessel does.

Q: Why does the induction plate stay cooler than a gas flame?

A: The heat is made inside the vessel, not in the plate. The plate only warms because the hot vessel sits on it.

Q: Is an induction range the same as an induction cooktop?

A: An induction range has induction burners on top and an oven below. An induction cooktop is only the cooking surface, and many Indian homes use a portable one.

Q: Does induction use less electricity than other electric cooktops?

A: It wastes less heat, because the energy goes into the vessel. Your actual bill still depends on the wattage and how long you cook.

Q: Why does an induction cooker stop when I lift the pan?

A: The field needs a magnetic vessel to work on. With no vessel, the sensor cuts the power, so nothing heats.

Q: Why can't I use my aluminium vessel on induction?

A: Aluminium is not magnetic enough for the field to heat it well. Use a vessel with a steel base, or an adapter disc if your manual allows it.