With the coffee maker circuit visible, we can see how the machine operates at a basic level:

The coffee maker is controlled by a simple on/off switch on the side of the machine. When the device is plugged into the wall, it receives consistent AC power that flows into the switch. However the circuit is broken so it does not begin heating until the switch is turned on.

Once the switch is turned on, current can flow through the white wire (blue tape) into two thermal fuses (216°C) which act as safeguards against overheating. From there, power flows through the heating system which contains about 17 ohms of resistance, and travels back out into the switch by the black wire