Sensor and Converters Overview

The converter is devices that convert one type of energy into another, such as converting electrical energy into light or sound, or create an electrical output corresponding to some physical parameters.

In this section on Input/Output Devices, we found that converters are devices that convert one energy form into another.For example, microphones convert sound waves into electrical signals, motors convert electrical energy into mechanical energy, or bulbs convert electrical energy into light.In both cases, Transducerscan be interfaced with electrical and electronic circuits in many forms to monitor or control the environment in which they are installed.

sensors and converters

There are thousands of converters to choose from for any application such as electrical, mechanical, chemical, biological, ultrasonic, etc.

Converters can be divided into input devices called "sensors" and output devices called "actuators".That is, the sensor is a device that receives or responds to an input signal.However, the actuator is a device that activates or moves something.

Below is a list of the main features related to Sensors and Actuators, as well as a summary of the converters that we have reviewed in this section.

Input Devices or Sensors

  • Sensors are"Input" devices that convert some kind of energy or quantity into an electrical analogue signal.
  • The most common forms of sensors are those that detect Position, Temperature, Light, Pressure and Speed.
  • The simplest of all input devices is the switch or push button.
  • Some sensors, called "self-generating" sensors, produce output voltages or currents according to the measured amount, such as thermocouple and photovoltaic solar cells, and the output bandwidth is equal to the bandwidth of the measured amount.
  • Some sensors, called "modulated" sensors, change their physical properties, such as inductive sensors, LDRs and pontiometers, according to measured quantity, such as inductees or resistance, and must be prerequisced to provide an output voltage or current.
  • Not all sensors produce straight linear output and linearization circuit may be required.
  • Signal conditioning may also be required to ensure compatibility between the sensors low output signal and the detection or amplification circuit.
  • Some kind of amplification is usually required to produce a suitable electrical signal that can be measured.
  • Instrumentation type Operational Amplifiers are ideal for signal processing and conditioning of sensor output signal.

Output Devices or Actuators

  • "Output" devices are often called Actuators, and the simplest of all actuators is LED,lamp or indicator.
  • Relays ensure good separation of low voltage electronic control signals and high-power load circuits.
  • Relays allow dc and AC circuits to be separated (that is, altering an alternating current path through a DC control signal or vice versa).
  • Solid state relays react quickly, are long-lasting, do not contain moving parts without arcs or splashes in contact, but require heat absorbers.
  • Solenoids are electromagnetic devices mainly used to open or close pneumatic valves, safety doors and robot-type applications.They are inductive loads, so a flywheel diode is required.
  • DC motors with permanent magnets are cheaper and smaller than equivalent winding motors because there is no field winding.
  • Transistor switches can be used as simple ON/OFF unipolar controllers, and pulse width speed control is achieved by changing the task cycle of the control signal.
  • Two-way engine control can be achieved by connecting the motor into a transistor H bridge.
  • Stepper motors can be controlled directly using transistor switching techniques.
  • The speed and position of a stepper motor can be accurately controlled using pulses to operate in open-cycle mode.
  • Microphones are input audio transducers that can detect acoustic waves in the range of infrared sound, audible sound or ultrasound produced by a mechanical vibration.
  • Speakers, buzzers, horns and sirens are output devices and are used to produce output sound, note or alarm.