Difference between actuator and sensor?

Sensors

feeding information to a circuit and they are applied to some electronic devices which produce electrical signals electronically such as ultrasonic sensor, water level sensors, and IR sensor

Actuators

generally, mechanical devices which produce signals but by mechanical means such as switches

Transducer

conversion of energy from one form to another

every Transducer is a sensor ( or has a one ) but not every sensor has to be transducer

Author - Abdallah Hegab