The buzzing sound you hear when a waffle iron is turned on is likely caused by the heating element inside the appliance. Waffle irons, like many other cooking appliances, use electric heating elements to generate the necessary heat to cook the waffle batter.
The buzzing sound is a result of the heating element rapidly heating up. When electricity flows through the heating element, it encounters some resistance, which causes the element to heat up. This process can create a slight vibration or buzzing noise as the element expands due to the heat.
The sound may vary depending on the specific design and brand of the waffle iron, but it's generally a normal and expected part of the appliance's operation. As long as the waffle iron is working correctly and heating up properly, there is typically no cause for concern regarding the buzzing sound.