Pretty much like a refrigerator.
Many years ago, a new technique was introduced named the inverter system. It costs a little more, but you will save money instead.
The inverter AC works a little differently than the old system. Here is how: When you start your inverter AC, it will start with 100% capacity immediately to cool down your room fast. When the temperature goes down, the system (fan and compressor) slows down to the temperature you chose. This means that when the system slows down, you probably cannot hear the AC working at all. The system will also save electricity.