Eli5: how do modern cutting tools with an automatic stop know when a finger is about to get cut?

Question

I would assume that the additional resistance of a finger is fairly negligible compared to the density of hardwood or metal

In: Engineering

Answer 1

There’s an electric current running through them. Your body conducts electricity, wood kinda doesn’t. As soon as it makes contact with you, the electric signal pulls the blade away. As fast as electricity can react, which is why in the ads you see people will barely have a scratch on them