question about induction cooking

The temp setting uses a sensor to detect the cooktop heat. This heat is what is transferred back from the pan/pot. So it's a fair approximation of the temp of the pan/pot bottom. Use the temperature settings for holding a simmer, setting a frying oil temperature. Holding a simmer in a small pot on a gas stove is tricky and may not be possible depending on the burner. With induction, size of the pot and quantity matters much less as the system monitors the temps.

I've found the temperature settings good for dark roux too as you have more control over how hot the pan gets without exceeding the temp and scorching the dark roux. If you had fine grained controls, it could be good for sugar work. My temperature settings on my unit are usually about 30 degree bumps, too coarse for sugar.

The temperature setting will also protect against a pan simmering dry and over-heating. Temperature setting cycles heat on and off. In an ideal situation, there wouldn't be a difference between bringing a pot of water to a boil by temperature or by power. But in the real world, the power setting works faster because the pan doesn't transfer heat to the water with perfect efficiency so you have a few off cycles in the temp setting comparison.  If you set the temp to something like 250, which the pan bottom is probably efficient enough in heat transfer to the water, it will never get that hot, and the unit will pour full power into a pot of water at that temp. Different units may use fuzzy logic to reduce the power as the heat approaches the desired temp so it doesn't over shoot.

When you use a wattage setting, It pours that much wattage into the unit continuously (unitl a "dangerous" temperature is reached, usually in the higher end of the 400s mine maxes out at 464. This is a reasonable choice as you're at or past the smoke point limits of most household cooking oil, and risk some damage to many pots/pans. But for blackening or a steak in cast iron, I'd like to go hotter still.

Think of the wattage settings as equivalent to a burner from low to high. The heat comes in continuously and you regulate the intensity.

There are some situations where the power and temperature settings are indistinguishable, particularly at full power/max temperature.

I bought an induction cooktop a few months ago and

this is exactly what I've been wondering about. 

Thanks for the great explanation.

please tell me about diffrent tempreture for diffrent recipe

Thank you! Nowhere in the instructions which came with my induction hob, nor in questions I've put elsewhere,nor in results which came up in a search on the Internet was there an answer as straightforward and comprehensive as yours. I've now cut-and-pasted your answer into the scanned version of my hob's user manual - which is where it should have been in the first place, as another poster has commented. Thank you again.
 

I can't imagine cooking like that,  It sounds like it only makes it more complicated, not less, and you have to second guess the machine, which is trying to think for you.  Sort of like driving with an automatic transmission

That and the fact that you can't toss the pans around.  What fun is it? 

With a compatible pan, it's funner than my gas stove. Funner for all the reasons that gas is said to be better than an electric coil hob. It heats FAST. It has immediate response. All faster and better than gas. With the inexpensive stand alone units talked about here, you don't have as fine grained control as a knob on a gas stove, true. But those kinds of controls are becoming more and more common on the installed units.

You can pick up the pan and toss the food around, no problem. While the pan is off the burner, it usually displays an error code, but when you return the pan, it's right back to business.

Induction burners run about 80% efficient, gas stoves about 35%. You can put more BTUs right into the pan and food, and not so much escaping into the kitchen.

And it's awesome for stir fry.