Electrical Signals

What device is used to convert variations in a physical parameter such as pressure, brightness, temperature, flow etc, into an electrical signal?

Hint
Multiple choice answers:
  1. Transducer
  2. Communication Signal
  3. Detector
  4. Transitivity
A transducer is an electronic device that converts energy from one form to another via electrical signal. Common examples include thermocouples, speakers, microphones, position/pressure sensors, and LEDs/lightbulbs.
Transducer