来自《耶鲁大学开放课程：生物医学工程探索第2集第2集》

and then the temperature stays the same inside the room

你设定温度后房间里的温度就保持不变
no matter what the temperature is outside.

不管外面温度是多少
Well how does that work?

那么它是如何工作的呢
It works by a control mechanism called negative feedback,

是通过一种叫做负反馈的控制机制
and the thermostat is measuring the temperature

探测器测量温度
and then sending a signal to a heater somewhere.

再把信号传给加热器
If the temperature drops below a certain level

如果温度降到一定程度以下时
it sends a signal, 'turn on the heat',

探测器会发送一个信号打开加热器
and that signal stays on

直到加热器再收到关闭的信号
until it gets a negative signal to turn off.

它就会一直开着
When does that negative signal happen?

什么时候会产生关闭信号呢
When the temperature gets above the level you want it to be.

就在当温度超过你想要的温度时