how refrigerators know when to beep when they’ve been open too long

Question

how refrigerators know when to beep when they’ve been open too long

In: Technology

Answer 1

There’s a switch connected to the door, which is connected to a timer.

Did you look inside the fridge?

Answer 2

There is a switch when the door opens to turn on the light. The same switch is hooked up to a circuit that checks how long the switch, thus door, is open.