In this tutorial, you will learn the difference between sensor and actuator. The main difference between sensor and actuator is that actuator is a output device and sensor is a input device.  First I will introduce you to actuator and then I will explain you about sensor and their types. Actuator and sensors are different parts of machinery upon which the working of machinery depends. Here we have brief introduction and the technical different between them.

Difference between sensors and actuators

Introduction to Actuator

The part of machinery upon which the movement and guidance of an apparatus is dependent is actually an actuator. Most of the actuators are guided by software because they turn the control sign into spontaneous action but in the past the actuators are based upon hydraulic, pneumatic, electric, thermal or mechanical means.


Some types of actuators includes;

  • Electric motors
  • Comb drive
  • Hydraulic cylinder
  • Pneumatic cylinder

Introduction to Sensor

For the detection of different actions and gestures of the surrounding a device or an element used is called sensor. After detection of any gesture it provides the information to the electronic device. Sensors can only work with other electronic components.


There are a large variety of different types of sensors. Some of them are listed:

Difference Between Actuator and Sensor

Sensors and actuators are the most important part in any machinery as they provide the information to do work. Sensor and actuator are widely used in are daily life routine in different mechanical, electrical or different equipments or devices.

Sensors and actuators have a number of similarities and dissimilarities in the functioning or processing. Here we have listed the differences between the actuator and a sensor.

  • The main difference between an actuator and a sensor is that the sensor converts the phyical gesture into electrical signals and do different works. Whereas, the actuator is responsible for the conversion of electrical signal to mechanical work.
  • Sensors measure discrete as well as continuous process variables. On the other hand, actuators are used to impel the parameters of both dicrete and continuous processes.
  • Sensors are widely used to original electrical signals in different electrical applia On the other hand actuators are very useful in the production of energy in the form of heat and motion.
  • Sensors are used as an input device because of the reason it is placed at input dork of the machine. However, actuator are used as output device as it is mostly placed at output port of the machinery.
  • Sensors are the one which acts as a brain because it provides information to do work.
  • Sensor provides you electrical energy by direct conversion of thermal energy with the sensor name thermocouple. Two metallic wires which are connected to the single terminal forms a joint. That joint is heated and the joints are provided with thr voltages. This effect was named after the scientist seedbeck coefficient or effect. In this effect the voltages ate directly proportional to temperature of joints. While there’s a type of actuator called bimetallic strip which converts thermal energy into mechanical output. When the material is heated the distance between different atoms or molecules increases. Because of large number of atoms in a material, the material expands considerably. The opposite reaction occurs when the temperature decreases, most of the metals contract.

Applications of sensor and actuators


  • Mechanical sensors are used to measure atmospheric pressure with the sensor named Barometer. Barometer tube is filled with mercury so when the atmospheric pressure increases the level of mercury in the tube also increases.
  • While in the mechanics, actuator gives the result in linear motion from the physical rotatory input given to the actuators. Screw jack is the common example of mechanical actuator. When the screw of the screw jack is tightened or rotated the legs of jack move together. Thus mechanical actuator converts mechanical rotation in linear motion.


  • Electrical sensor is an other type of sensor which is used in sensing the quantity of electric current which passes through the conductor. This process involves different energy conversions i.e; electrical to magnetic and magnetic to mechanical rotation.
  • While electric motor is a type of electric actuator. Type of electric actuator is DC motor. DC motors operate by the current flowing through the coil. Which creates magnetic field around the coil. Electrical actuators converts electrical energy to magnetic energy to mechanical output in the form of motion.


  • Sensor in the automotive determines whether the consumption of fuel is smooth or is igniting. Ignition of the fuel causes major damages to the car like breaks engine rings, or effects bearing and many more. With the help of sensor we are able to know if the fuel is burning adequately or is colder. Because the cold fuel is denser and restricts the car to move smoothly.
  • However in the automotive engines, an actuator controls the futile speed of car. Air flutters are adjusted by actuator and actuator is responsible for the enhancement of force. Actuators are made with such technique to provide driver or passengers with full safety. Actuators are used to control the redistribution or exhaust gas to increase performance.


  • Hydraulic sensor are very popular in the field of water distribution. Hydraulic sensor are used to measure the pressure and flow of water. These sensors are used as gauge. In water distribution system the hydraulic sensor is used to measure momentary pressures and pipe bursts. Hydraulic sensor is also used in measuring the velocity of water. Electromagnetic and vortex swirl measurements are the modern methods of flow meter.
  • On the other side hydraulic actuators for the easy sliding of a piston contains a cylindrical hollow tube. The movement of a piston in a single direction means that the pressure id applied only on the one side of the piston. This is known as single acting. During the movement of piston in the single direction, a spring is used for the return blow. There’s an other type of pressure acting that is known as double acting. In this pressure is applied across the both sides of the piston. Pressure contradiction among the different sides of the piston is thr process which causes the piston to move.


  • Sensors plays vital roles in robotics. Sensors are the one that allow the robot to move, hear, see and touch. The use of sensor in robotics increased the performance of robots to large extent. With the use of sensor the robots are made in the same way to act like a human being.
  • On contrary actuators are used to make mechanical movements. We could say actuator in other words the muscles of robots.

Sensors and actuators, both play very important role in a machine.


  1. The main difference between a sensor and an actuator output device. Gears are generally toothed wheels that connect with the teeth on other gears to transmit movement to another part.


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