Harmful Effects of Led Lights

Harmful Effects of Led Lights

Led lights are increasing day by day due to low energy consumption, but their many harmful effects of led lights. In this article i will discuss about effects of led lights on the eyes and which lights are good for eyes.

Effects of LED light on the eyes:

The light-emitting diode is the device that emits rays when current flows through them. LED lights are efficient in both energies as well as in case of price. LED lights are emitting blue light that causes severe damage to our eyes. LED’s were emitting high energy blue lights having short wavelengths that are the cause of significant issues to eyes like fatigue, dry eyes. The blue lights are not new for us; it is coming from the sun and also present in old yellow bulbs emitting a small amount. Close and continuous exposure from our mobiles tablets computer to LED blue light, although it has a minimal amount as compared to fluorescent LED lights but causes irreparable damage to eyes. Computers, tablets, mobile phones have these LED lights, and our enthusiasm for using these lights is increasing day by day, and in return, our eyes have to pay for that.

Diseases caused by LED lights:

According to American studies, the ratio of harmful effects of LED lights to eyes in evening and night is more significant as compared today. Retina mostly affected by LED, which is light-detecting nerve tissue at the back of the eye and a considerable portion of the eye. They cause irreparable loss to the retina and also decreases the sharpness of our eyes.

Sánchez-Ramos said.

“Eyes are not designed to look directly at the light — they are designed to see with light,”

Following are the diseases

  • Macular degeneration
  • Cataract
  • Dry eyes
  • Tiredness or eyestrain

Macular degeneration:

Continuous exposure to LED lights quickens the maturing of retinal tissue, causing a decrease in visual sharpness and specific degenerative ailments, for example, age-related macular degeneration. As we all know, Macular degeneration is the severe irreversible vision disease of an older adult over age 60, but continuous exposure destroys the retinal layer called Macula.


LED lights are also responsible for cataract disease. Water and proteins are the major constituents of the eye lens. Proteins are arranged in layers, but with age, these proteins layers form clusters due to which cloud-like formation is created on eyes. It is the primary cause of blindness in the world. A person having no interaction with LED light might have cataract disease after the age of 40, but the person using LED lights with continuous exposure will have this disease before 40. Because blue lights LED, have short wavelength but high energy due to which this energy cause disruption in the protein layer and form clumps or clusters.  

Dry eyes:

Dry eyes are the condition of eyes when they are not ready to leave a “tear film” that washes and alleviates the eye each time they blink. The sight at that point gets irritated and dry. This irritation and dryness brought about by dry eye cause vision problems. In rare cases, dry eye can become a severe problem if not consider and treated well. Side effects of eye fatigue incorporate sore or disturbed eyes and trouble focusing.

Tiredness or eye strain:

The tiredness of eyes is also a significant problem, also known as eyestrain. Probably the most common cause is little sleep, sensitive eyes having allergy problems in the past, using a computer for a long time, poor lighting conditions, or have the light of high intensity, driving a vehicle for delayed timeframes, or studying for a longer time.

If you want to know about more you can go to this link

Characteristics of transducer

Electrical Transducer & Characteristics of transducer

In this article I will describe about electrical transducer and characteristics of transducer. What are the main types of characteristics of transducer, how they work and their applications and advantages.


Transducer is a physical device that receives energy from one system and transmits it into same form or another form of another system. There are three main parts included in its working principle. First is sensor, second signal conditioning unit and last one is data representation. A sensor is an electronic device that sense energy or some physical quantity i.e temperature, pressure, speed, water level etc. or in other words sensor is used to detect some physical quantities at specific level. If any change in the input, sensor is able to find its reason. The nature of physical quantities is non-electrical. After passing through sensor, signal conditioning unit is applied like amplifiers, analog to digital converter, modulators, filters, rectifiers. It is implemented with respect to desired output of a signal. At last data is represented to any measured scale like a LCD display or any other form.

Efficiency of a transducer is the ratio of output power to input power.

E(%) = x/y *100

y = Output power,  

x = input power  

If you want to read more about transducer you can click on this link

Characteristics of transducer

There are two types of characteristics of transducer to define the performance of a system. It is important to define performance parameters of a system.

  1. Static characteristics
  2. Dynamic characteristics

Static characteristics

In this type of transducer, the set of performance is established by static tuning. It maintains static performance of parameters i.e precision (accuracy), threshold, sensitivity, repeatability, stability, drift, linearity, resolution, reproducibility, differential linearity, integral linearity, noise, maximum input, dynamic range, saturation level, hysteresis, input and output impedances. The measured parameters are varying slowly with respect to time or take a constant value.    

  1. Accuracy

It is defined as the ratio of measured value to standard value. It indicates the error value of a system. When the measured value goes to the nearest of ideal value or standard value its accuracy becomes higher.

  1. Resolution

The smallest difference of images or figures is discriminated of some type of units i.e pixels or inches etc. When an image is measured in pixels and compared its value to standard image size then it is called as a resolution of that image.

  1. Repeatability

When a number of outputs are measured consecutively by applying the same value of input during the same operating conditions then it called as repeatability.

  1. Hysteresis

Hysteresis is one the main characteristics of transducer which is measured for some parameter and it gives differ value from the previous one at display by applying the same value of input. The input value gives an increasing behavior with the respect to another parameter which shows decreasing behavior of the same system. Hysteresis loop of elastic is shown in figure. 

Figure:  Hysteresis loop of elastic characteristics of transducer

characteristics of transducer
  • Linearity

The number of increments of the input are same with respect to the output increment then it is known as the linear increment or linear output.

  • Threshold

The minimum value is observed by the observer or standard value is set for a system. When measured value is noticed which is above the desired level then value is to be “above the threshold value”. In figure 1.2 threshold level is represented.

Figure:  threshold voltage or time over threshold shows

threshold voltage or time over threshold shows

Dynamic characteristics

In this type of transducer, the set of performance is dynamic. When the performance parameter is measured and varies with respect to time then parameter said to be dynamic for a specific system.  It does not maintain the static performance. It includes speed of response, fidelity, bandwidth and dynamic error.

  1. Bandwidth

The range of frequency which is traveled or transmitted to the desired destination within a given band is said to a bandwidth of a signal.

  1. Response time

The quantity is measured in that time and new equilibrium value of quantity is measured within a time is known as a response time.

  1. Settling time

Settling time is that time in which is not detected any variation of a signal. Variations can occur change of physical quantity. In figure 1.3 shows settling time of PID controller.

  1. Rise time

The rise time is that in which the measured quantity is observed linear behavior by the observer. See figure 1.2, the graph of PID controller.

Figure:  Settling time and rise time of proportional integral derivative

Types of Transducer

There are two main types of transducer which is used in our applications.

  1. Electrical transducer
  2. Mechanical transducer

Electrical Transducer

The physical changes of measured quantities at the electrical output of transducer for an electrical system are known as electrical transducers. It is further divided into Active Electrical Transducer and Passive Electrical Transducer.

Active Electrical transducers are those in which active components are included in a system like Magnetostrictive Transducers, Photoelectric Transducers, Piezoelectric Transducers, Electromechanical Transducers, Electrochemical Transducers, Ionization Transducers, Thermoelectric Transducers etc.

Passive Electrical Transducer are those in which passive components are included in a system like Resistive Transducers, Capacitive Transducers and inductive Transducers etc.

Mechanical Transducer

The physical changes of measured quantities at the mechanical output of transducer for a mechanical system are known as electrical transducers. The measured physical quantities are temperature, pressure, level of a liquid, torque, force, flow rate etc.

Types of transducers and their applications

  1. Photo electric transducers

Voltages are produced, when the light is come to the photo electric transducer.

  • Ultrasonic transducers

These type of transducer is used to measure flow rate or floe level in ultrasonic waves.

  • Piezoelectric transducers

These type of transducers are used to measure force, acceleration and pressure. Voltages are produced by applying force in it.

  • Hydro-pneumatic transducers

These type of transducers is used to measure velocity, speed, flow level of water. Devices of pitot tube, turbines & vanes are used in it.

  • Pressure transducers

These are used to measure the physical quantities which is used in converting pressure energy into electrical energy. They are used in sensing of pressure, altitude, flow rate, level of depth. It is also used in vehicles in which converting force into electrical energy.

  • Temperature transducer

This type of transducers is used to convert temperature into different forms of energy like electrical, mechanical or pressure.

inductive transducer

inductive torque transducer working principle

What is a transducer?

The device is used for the conversion of physical quantities into proportional electrical quantities such as in voltage or electric current. It plays an important role in the instrumentation system. Inductive torque sensor is use for measurement of torque of motor’s shaft. Inductive torque transducer working principle is simple just to getting a electrical signal from transducer sensor. It can measure physical quantities like displacement, temperature, motion, level, pressure, etc. The output which is obtained from the transducer is in the electric form and its equivalent to the measured quantity. There are numerous types of transducer but in this, we will discuss inductive transducer only.

What is Inductive transducer?

It is an electrical device used to convert physical motion into modifying inductance within. It is a self-generating type. Like it uses the principle of fundamental electric generator which means when a motion among a conductor as well as magnetic field induces a voltage within the conductor.

inductive torque transducer

Self-inductance change:

It can be derived by


N= no. Of twists of coil

R= magnetic circuit reluctance


It primarily consists of the two-part of the coil, the first one is the movable magnetic core, the element that senses pressure. Not only this has the inductance of the coil changed as the AC voltage is applied to that. Moreover, there is a direct relationship with the inductance increase and the current decrease with the help of the coil. 


  • If there is a significant change in the quantity to be measured, then there is a significant change in the inductance.
  • The electromagnetic induction’s principle is applicable here, which is primarily used to measure or to detect the things.
  • The foremost fundamentals are the Famous law of Faraday
  • The principle of a fundamental electrical generator is applicable here. 


A magnetic field develops when a current is flowing through the active inductive transducer then instantly the current flow by the circuit that contains an effective inductor when the magnetic field changes through it. This effect is primarily used to indicate all the metallic jobs that usually associates with the field of the magnetic. 

However, the objects that are non-metallic like liquid or some different type’s dirt that won’t react with the field of the magnetic, this is the reason that the inductive sensor could effectively perform in any of the dirt conditions.

There are two types of inductive transducers available such as simple inductance & two-coil mutual inductance. The best example of an inductive transducer is LVDT (Linear variable differential transformer).

  • Simple inductance

A single simple coil that is used as a transducer can be termed as the mechanical element whose displacement has to be evaluated, after that it will change the path of the flux permanence that is originated from the circuit. The final equivalent output is the modified version of the inductance circuit. Moreover, the output of the circuit can be adjusted corresponding to the value of the input. Hence this is the foremost reason that this value could be calculated. 

  • Two-coil mutual inductance

This is the second most fundamental and the different types of coils that are arranged in it. With the help of the external source of power, this primary coil will be generated. However, the focused output could be attained. Moreover, the input of the mechanical and the output are proportional to each other. 

Advantages and disadvantages of inductive transducer

  • It is used for measuring the displacement, for which we use one of its types known as Linear Variable Differential Transformer (LVDT) to measure displacement in terms of the voltage difference between two secondary voltage.
  • It also used to detect the motion of the equipment, for which we the device we use known as a proximity sensor. It also measures position, touchpads.
  • It is used for the detection of metals, to find out the missing parts otherwise count the objects.


  • It will reduce load effects.
  • Higher the responsivity of transducers.
  • Strong against ecological quantities.


  • Due to the side effects, the operating range will be reduced.
  • Sensitive to the magnetic field.
  • The working temperature should lie under the cutie temperature.
Industrial Application of inductive Transducer

The application of inductive transducers finds in proximity sensors also to measure position, touchpads, dynamic motion, etc.

Inductive torque transducer works to measure torque of motors and moving machines

In industries this device is used as a traffic light sensor.  It is also used as metal detector. As the device is able to detect metal under the ground.  They are very useful in industries as this device as a proximity sensor is able to detect the presence and absence of an object other than its position. 

So, in this, we have discussed the inductive transducer and its applications. We go through its structure, the principle of working, where it applies, its advantages and disadvantages of uses and its working phenomenon. As we know any electronic device has some good as well as a bad impact also but besides this, it has numerous applications which are helpful for us in any sort of way. In a modern era, this device is helpful in maintaining the motion, metals, temperature, and pressure of the object by detecting them with the help of a magnetic field. It has two coils one is simple and the other one is a mutual two coil. Both have different working phenomenon and has different techniques to be work on.inductive torque transducer working

Proximity Sensor types & their applications in industries

Proximity Sensor Types and Uses in Industries

To detect the presence of an object without being into physical contact with the object, proximity sensors are used. The proximity sensor works on different principles to sense different objects. Different types of sensors are used in for different scenarios where the detection of the objects is required through non-physical contact. For example, inductive type proximity sensor used for metallic objects and capacitive type sensor for non metallic objects.

Mainly there are two types like inductive and capacitive. But proximity sensors are further classified into several types depending on the principles that are used for the detection of an object without any physical contact. They are also classified according to the type of material they sense.

Here is the list of some basic types of the proximity sensor.

Inductive Proximity Sensor:

The inductive sensor is the type of proximity sensor used to detect metallic objects without being in physical contact with the object. The principle under which the inductive proximity sensor is the electrical principle of inductance. The target object is detected when an electromagnetic force is induced in the object due to the fluctuation of the current.

The inductive sensor makes use of an oscillator circuit for the generation of the high frequency of the electromagnetic field. When an object comes in touch with the field, then at the surface of the object an eddy current will be produced. The eddy current absorbs radiated energy from the sensor, this will result in the loss of energy and also the strength of the oscillator will be changed.

inductive proximity sensor working

The changes in the strength of the magnetic field will be detected by the sensor detection section of the sensor, it will then trigger a solid-state output level if the strength of the magnetic field starts decreasing.


  • The accuracy rate is high
  • Switching rate is also very high 
  • Harsh environmental condition is not a limitation for this type of proximity sensor.


  • Only suitable for the detection of metallic objects
  • Range limitation

Capacitive Proximity Sensor:

Capacitive sensors are almost similar to inductive proximity sensors, the only difference between these two types of proximity sensors is that the capacitive inductor produces electrostatic instead of the electromagnetic field. 

The formation of the sensing surface is made using two metal electrodes, the oscillator produces the electrostatic field between two plates. Whenever a metallic or non-metallic object meets the electrostatic field, the capacitance of the oscillator changes. 

capacitive proximity sensor working

The oscillator circuit begins to oscillate and changes the state of the output of the proximity sensor as a result when it reaches a certain value of amplitude.


  • Detection of metal and non-metal object is possible with the help of capacitive sensors
  • Very high speed of detecting an object
  • Very good stability
  • Power usage is efficient 
  • The cost is very low


  • Temperature and humidity effects the performance of the sensor
  • The accuracy level is less as compared to the inductive sensor
  • Designing very difficult.
Photoelectric Proximity Sensor:

This sensor works on the principle of light for the detection of objects without any physical contact with the object. There are 2 basic types of photoelectric sensors 

  1. Reflective sensor
  2. Through-beam sensor

The reflective sensor works by the emission of a beam of light that hits the object and reflected the sensor, usually in the same physical house as beam emitter.

The through-beam sensor, on the other hand, comprises two parts, one is an emitter, also known as a source of light and the other is a detector or separate receiver. Whenever an object breaks the beam of light, the detector will register this break.


  • It is also known as an all-purpose sensor because it has the capability of sensing all types of material.
  • The life span is longer
  • The sensing range is good 
  • It is very reliable 
  • The response time is very fast
  • The cost is very low


  • Lens gets contaminated 
  • Two separate components are required.

All the different proximity sensors types and their application in industries are well described and their comparison you can see in following image

Proximity sensor types

If you want to learn about working principles for all above sensors you can check this link

All images credit goes to machinedesign

What is Proximity Sensor in Mobile

What are Proximity Sensors

As the sensor name suggest, Proximity sensor is a sensor which can detect other object, which comes closer to it, up to a certain range of distance without any physical connection. The covering distance of sensor is called sensing range which varies according to size of sensor, for example an 18 mm diameter inductive sensor will have sensing range for 5 mm to 8 mm. See datasheet here so you can get idea that what is proximity sensor.

The maximum distance at which sensor can sense other object is called nominal range, which is also depend on size of sensors. There are some sensors for which you can adjust their sensing and nominal ranges. You can see here how adjustable proximity sensor works. Proximity sensor are highly reliable and long functional life because of no mechanical parts and no physical contact between sensor and sensed object.

How it works

Proximity sensor emits electromagnetic field or a ray of electromagnetic radiations, infrared, for instance, and wait for changes in these radiations or bounce back signal. The object which is sensed by proximity sensor is often called sensor’s target object. The target demand for different proximity sensors is different. For example , a capacitive proximity sensor or photoelectric sensor often demands for plastic target which is more suitable for them and an inductive proximity sensor always want a metal object as sensor’s target.

Proximity sensor working
proximity sensor working

Proximity sensor types

There are different types of proximity sensors but mainly are two by which they known.

  1. Inductive type
  2. Capacitive type

Inductive type can detect metal objects and capacitive type can detect any object which come closer to them. If you want to check other types you can view by this link.

Proximity sensor uses

Proximity sensors have huge applications across every technological field. They finds application in industrial and manufacturing areas. They sense material and then response some type of action or simply tell about presence or absence of that material. The most important feature of these sensor is that they don’t require physical connection with their target which is being sensed. That is why they are often called non-contact sensors.

Every type of sensor has its own technique of use for a specific operation in any device. Here I will tell you about the applications of proximity sensors in android and IOS.

what is proximity sensor in mobile

I hope now you are known by this fact that proximity sensor works when anything come close to it. Here i will tell you about working of proximity sensor in mobile.

Large touch screen displays use huge battery power. So it should be turned off while you its not in use like calling someone or when the phone is in pocket. In that case proximity sensor turn off your mobile screen, as in both case mobile screen is close to your ear/cheeks or body in pocket. In such cases proximity sensor activate, sense object and send a signal to mobile processor to turn off display.

There are some other methods also, that are used for proximity sensing. For example, detecting the change in capacitance, inductance, magnetic field or even techniques like sonar. But, I doubt if they are used in mobiles. Thank you for your reading.

Please feel free to ask me anything about it.