The device that regulates heat on a stove is called a "burner control knob" or simply a "heat control knob." It is a dial or knob typically located on the front or top of the stove that allows you to adjust the intensity of the heat produced by the stove's burners.
The burner control knob is used to turn the burners on and off and set them to different heat levels, ranging from low to high. By turning the knob, you can control the flow of gas or electricity to the burner, thus adjusting the flame or heat output accordingly. This allows you to cook at various temperatures and control the cooking process for different types of food.