The oven's buzzing. What's going on?

There are three main sounds when the oven is working.

The first: the sound of the oven shell. When the internal temperature of the oven is increased, it will cause the metal panel to expand and shrink, which will cause a sound, which is normal, and it is good to use several times, you can rest assured that it can be used.

The second: the sound of the oven timer. When the oven is working, some oven timers will make a ticking sound, which is normal and can be used with confidence.

Third: the sound of oven parts working. There is occasionally a little sound when the oven parts are operating, which is normal and can be used with confidence.