ISFET

ISFET stands for Ion Sensitive Field Effect Transistor. It's something like a tiny computer chip with a sensor built in. The sensor is really sensitive to ions, which are tiny charged particles like molecules in the air. When ions come near the chip, it changes the electric signal it produces. That signal can be used to measure changes in the environment, like the temperature or how acidic something is. People use ISFETs to measure things like the amount of salt in water or the pH of a liquid. ISFETs can also be used to detect chemicals in the air and dangerous gases.