How to a sensor apply a voltage




Have a look at this picture. It's a simple heat sensor. Though it looks like it's really simple, I don't fully understand how the middle pin works.

How can a voltage be applied? I thought it was merely an abstract concept for the difference in potential electrical energy.

And how does it work for this heat sensor in particular?

Best Answer

Here's a link to the spec sheet. I'd call it a temperature sensor. (heat has units of energy.) You have to apply power so the internal circuitry provides an output voltage.

It looks to be a silicon band gap temp sensor described here