Test the surface temperature of the heating wire to see the color of the heating wire. As the temperature increases, it changes from dark red to bright red, and then from close to yellow to white, reaching a dazzling blue-white color. Based on this fact, the temperature of the object can be judged from the color of the object's light emission. The heating wire has a high temperature (1100°C) and is yellow-red. The heating wire has a higher temperature (1300°C) and is yellowish-white. Achieve dazzling blue-white (1500°C) or above. So testing the surface temperature of the heating wire is actually to watch its color change.
An important parameter of the heating wire is the surface power. If the resistivity is too large, after a certain current is passed in, the surface power will be large; if the resistivity is too small, after a certain current is passed in, the surface power will also be small. Therefore, for low-power electrical appliances, use small diameter and small current, but the current The size is determined by the size of the resistance. The greater the current in the heating wire, the higher the temperature of the heating wire. On the contrary, the smaller the current in the heating wire, the lower the temperature of the heating wire. The length and diameter of the heating wire are calculated in this way.
