A switch that can be operated electrically is known as a relay. It consists of several operating contact terminals as well as a group of input terminals for multiple or single control signals. The switch might come with a different number of contacts in several contact forms, like break contacts, make contacts, etc.

Relays have found its uses at places where several circuits need to be controlled by a particular signal or where it is important to control the circuit by a low power signal which is independent. Firstly relays were utilized as signal repeaters in long-distance telegraph circuits. Here they used to revive the signal rolling in from one circuit by broadcasting it on another circuit. Relays were utilized excessively in early computers as well as telephone exchanges to carry out logical operations.

The basic version of relays takes the help of an electromagnet to open or close the contacts, however, other working standards have been concocted like the solid-state relays which utilize the semiconductor properties for controlling. Relays that comes with multiple operating coils and adjusted working attributes are utilized in protecting electrical circuits from faults and overload. In current electric power frameworks, these capabilities are taken care of by digital instruments known as protective relays.

Time Delay Relay

The arrangement of timing relays is made in such a way that it causes a delay in operating their contacts. To cause a very small delay, a copper disk is placed in between the moving blade assembly and the armature. The electric current which flows in the disk keeps up the magnetic field for a brief timeframe, protracting discharge time. For a bit longer delay, a dashpot is utilized. A piston loaded with fluid that can escape slowly is referred to as a dashpot. In this case, both oil-filled, as well as air-filled dashpots, are taken help of. To vary the time period, one can either increase or decrease the flow rate. The installation of a mechanical clockwork timer is done for long time periods. Relays may either be field adjusted or organized for a fixed time span or set remotely from a control panel. Presently we have relays that come with a microprocessor that offers accuracy timing over an extraordinary range.

Today we also have relays that are made with a “shock absorber” mechanism to prohibit full, immediate motion at the point when the coil is either stimulated or de-invigorated. Thus it provides the relay the option of time-delay actuation. This kind of relays can be manufactured to result in a delay armature motion on coil Energization or De-Energization or even both.

The contacts of time delay relays should be specified not simply as closed or open, but also whether the delay gets operated in the opening direction or the closing direction.

This was all we have regarding the time delay and timing relays. Hope you liked the article. Brands that manufacture them are TE Connectivity, Littelfuse and Crouzet. Make sure to go through them using the links as provided. Thank you for reading.

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A stepping motor or a step motor or a stepper motor is referred to as a brushless DC electric motor that partitions a full pivot into various equivalent steps. The position of the motor can be made to hold and move at one of these steps without any rotary encoder for feedback.

Basics of operation

There is a continuous rotation of brushed DC motors whenever a DC voltage is given across their terminals. The stepper motor is popular by its functionality of changing input pulses (square wave pulses) into an accurately characterized augmentation in the pole position. Each pulse makes the shaft to move by a fixed angle.

Stepper motors come with multiple "toothed" electromagnets that are placed around a central gear formed in the shape of an iron. The electromagnets are made to energize by a microcontroller as well as an external driver circuit. To carry out the turning motion in the motor shaft, firstly, power is supplied to the electromagnet which attracts the teeth gear magnetically. When the teeth gear lines up with the first electromagnet, they are somewhat balanced from the succeeding electromagnet. Now as the following electromagnet is switched ON and the previous one is switched OFF, the gear turns marginally to line up with the following one. This process is then repeated and each of these rotation is known as "step".

The electromagnets’ circular arrangement is split into groups, each group is known as a phase, and every group comes with an equal number of electromagnets. The number of groups is selected by the creator of that particular stepper motor. Each group's electromagnet is interleaved with other group's electromagnets to establish a uniform pattern of arrangement. Let’s understand it with an example. Assume that the stepper motor consists of 2 groups A and B. Along with that it has 10 electromagnets. The grouping will be like ABABABABAB.

Electromagnets that are within a particular group are all energized together. As a consequence, the stepper motor with more phases regularly has more wires to operate the motor.

Advantages

• Low speed and high torque at startup.
• Ease for control accomplished.
• Construction is simple.
• Ruggedness
• It can be operated in an open-loop control system.
• Low maintenance.
• Will surely wok in any kind of environment.
• Less chance to slip or stall.
• It can be utilized in robotics.
• The input pulse is proportionate to the rotational angle.
• Highly reliable.
• Full torque at standstill.
• It provides a quite good response to reversing / stopping / starting.
• As there are no contact brushes in the motor, they are very much reliable. Thus the motor’s life is dependent completely on bearing’s life.

Applications

Stepper motors are commonly used in flatbed scanners, compact disc drives, computer printers, slot machines, image scanner, intelligent lighting, CNC machines, camera lens as well as in 3D printers.

Hope you liked the article on stepper motors. Brands that manufacture them are Applied Motion, CUI and Pololu. Make sure to follow the links as provided.

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LCD Touch panels serve both as input as well as an output device. They are generally placed above any electronic visual display of an information processing system. The users can operate the information processing system or even can provide input just by touching the screen by fingers or with a stylus.

Now, LCD Touch Panels’ basic principle of working is based upon that of an LCD. It will be good for us to get accustomed to LCDs. So let’s begin with it.

The LCD consists of a flat panel like display which takes the help of light modulating characteristics of liquid crystals. Instead of emitting light directly the liquid crystals use a reflector (or a backlight) to generate images in monochrome or color. LCDs are accessible to show a discretionary or a fixed picture with less info content, which can be shown or covered up, for example, digits, 7 segment displays like in digital clocks or preset words. Depending on the polarizer arrangement LCDs can either be ON or OFF. On blue LCDs, the optical fibers are summed with white to provide its characteristic appearance.

LCDs have found its way in several applications like computer monitors, aircraft cockpit displays, instrument panels, and LCD televisions. Small LCD screens are used in calculators, smartphones, watches, digital cameras, etc. It is also utilized in consumer electronics products like clocks, video game devices, and DVD players. LCD screens have completely replaced bulky and heavy CRT (Cathode Ray Tube).  Today they are available in several sizes than CRT. It should also be noted that some LCDs are also getting replaced by OLEDs. It is so because they can be easily converted into different shapes, has wide color gamut, low response time, virtually infinite viewing angles and color contrast, slimmer profile and weights lesser than an LCD.

Advantages of using LCDs:

• Light, thin and compact.
• Power consumption is low.
• The amount of heat emitted during emission is also less.
• No geometric distortion.
• A sharp image is generated when operated at native resolution.
• Discharges no bothersome electromagnetic radiation.
• Can be made in practically any size or shape.
• Offers Masking Effect – The LCD masks the effects of grayscale and spatial quantization to establish an illusion of higher picture quality.
• They are not affected by any magnetic fields (including the Earth).
• Can be constructed using narrow frame borders. Thus, enabling several LCD screens to get lined up side by side to make up what resembles a big screen.

Disadvantages of using LCDs:

• There is a chance for loosing up of contrast at high temperature.
• At low temperature, the response time is much slower.
• Thermalization might take place in case of bad thermal management.
• Stuck or dead pixels might take place during the time of manufacture or after a certain span of its use.

This was all we have regarding LCD and LCD touch panels. Hope you liked it. Brands that manufacture them are Fujitsu, NKK Switches and 3M. Make sure to follow them using the links as provided.

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A VFD or a Vacuum Fluorescent Display is a display device that was used on purchaser gadgets gear like car radios, video cassette recorders, and microwave ovens.

A VFD follows the principle of Cathodoluminescence which is much similar to that of the CRT (Cathode Ray Tube). The only difference is that they can be operated at a much lower potential difference. Each tube present in a VFD consists of an anode coated with a phosphor that is bombarded by electrons transmitted from the cathode fiber. In addition to that, each tube in a VFD has a mesh control grid.

A VFD produces an exceptionally splendid light with high contrast and can support display components of different hues. The standard illumination quantity for a VFD is around 640 cd/m². The VFDs providing high brightness operate at 4,000 cd/m² and that of the experimental components is as high as 35,000 cd/m² . The brightness of the display and the selection of color altogether influence the lifetime of the tubes. It ranges from as high as 30,000 hours for the most commonly produced green light to as low as 1,500 hours for a vivid red. In the past, cadmium was used as VFDs metal but now they are replaced by RoHS-complaint VFDs.

VFDs can display multi-segment Alpha Numeric characters or 7 segment numerals. By and by, there is little breaking point to the shape of the picture that can be shown: it depends exclusively on the state of phosphor on the anode(s).

The very first VFD was the DM160 made in 1959 by Philips. This was the single segment VFD. The 1^st multi-segment VFD was the 1967 Japanese single digit, 7 segment device. The displays started to get common on calculators as well as other purchaser gadgets gears. In the late 1980s, a huge number of units were made yearly.

Use:

Along with brightness, VFDs are inexpensive, rugged, and can be easily arranged to show a wide assortment of customized messages. In contrast to LCDs, VFDs are not restricted by the reaction time of adjusting liquid crystals. Thus, they can carry out their functions normally in cold temperatures. One of its biggest drawbacks of VFDs was that they used to consume a large amount of power than a simple LCD. This was viewed as a huge disadvantage for battery-worked gear like calculators and as a consequence, these VFDs ended up its use in devices that were given power using an AC source.

In the 1980s, VFDs found its use in automobiles for digital displays in odometers and speedometers. Their high brightness feature made them well suited for cars. From 1979 to the mid of 1980, VFDs were also used in portable electronic game units. VFDs also served a piece of good equipment for triode amplifiers.

This was all we have regarding Vacuum Fluorescent Display. Hope you like reading the article on it. Brands that manufacture them are Noritake, Matrix Orbital and Newhaven Display. Make sure to follow them using the links as provided.

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Display modules are popular devices that enrich people with visual information. One of the main motives of display modules is to simplify the sharing of information. There are several displays present but in this article, we are going to focus on two of the most important ones i.e. LCD (Liquid Crystal Display) and LED (Light Emitting Diode). And at the end of the article, we will give a glimpse of OLED (Organic Light Emitting Diode). So without wasting much words let’s begin this blog.     

2.LCD (Liquid Crystal Display)

The LCD consists of a flat panel like display which takes the help of light modulating characteristics of liquid crystals. Instead of emitting light directly the liquid crystals use a reflector (or a backlight) to generate images in monochrome or color. LCDs are accessible to show a discretionary or a fixed picture with less info content, which can be shown or covered up, for example, digits, 7 segment displays like in digital clocks or preset words. LCDs have found its way in several applications like computer monitors, aircraft cockpit displays, instrument panels, and LCD televisions. Small LCD screens are used in calculators, smartphones, watches, digital cameras, etc. It is also utilized in consumer electronics products like clocks, video game devices, and DVD players.

 2. LED (Light Emitting Diode)

LED is a light-producing semiconductor which discharges light when electric current moves through it. The electrons present in the semiconductor get attached with electron holes and release photons (energy). The shade of the light is dictated by the vitality required for electrons to overcome the bandgap of the semiconductor. White light can be generated by a film of a light-emitting phosphor on the device. LEDs have several advantages over an incandescent light. They are:

• Long Lifetime
• Small Size
• Fast switching
• Improved physical robustness

LEDs have found its use in automotive headlamps, traffic signals, plant growing light, aviation light, etc.

As we have got some ideas regarding LEDs, let's look upon OLED which is one of the popular type of LED present in the market.

                             OLED (Organic Light Emitting Diode)

OLED, popularly known as Organic EL diode, is a Light Emitting Diode where the layer of emissive electroluminescent is made up of organic compounds which generates light when electric current passes through it. OLEDs have found its use in devices like computer monitors, screens used in televisions, portable game console, smartphones, and PDAs. As the OLED display emits visible light there is no use for a backlight. Thus, it is lighter and thinner than the LCD. Even though an LCD uses cold cathode fluorescent lamps but still in a dark room an OLED screen can attain a much higher contrast ratio than an LCD.

Now, OLED can be divided into two categories.

• PMOLED – This stands for Passive Matrix Organic Light Emitting Diode. In this type of display, each row is controlled successively, individually.4
• AMOLED – This stands for Active Matrix Organic Light Emitting Diode. It takes the help of a thin film transistor to switch and access each pixel (ON/OFF). Thus, OLED of this category makes large display and high resolution possible.

So this was all about popular Display Modules. Hope you liked this article. Popular brands that makes display modules are 4D Systems, Riverdi and MikroElektronika. Make sure to check them out using the links as provided.

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An LCD controller or LCD Display driver or an LCD Driver is an integrated circuit that offers an interface between the LCDs and the Microcontroller (MCU) or Microprocessor (MPU) system. Generally, a standard parallel or serial electronic interface is used for connection with MCU or MPU. LCD Drivers can be discrete chips executed in standard semiconductor chip bundles, with enormous I/O interconnects to a different LCD glass through gadgets like bonded flexible looms or elastomeric connectors. To beat the extremely high I/O interconnection necessities of the controller to the glass, the controller chip can be bonded straightforwardly to the glass, with the serial interface and power supply being the main I/O associations.

                                                        The above figure is that of an LCD circuit.

Display drives drive a matrix of liquid crystal segments or dots. The enormous number of spots broadens the achievable number of ports that can be associated with the chip. To beat this exceptional technique for driving, a dot matrix grid is implemented. This is accomplished by implementing the LCD as a cluster, or network of lines and sections, and driving the lines and segments by exceptional waveform shapes. The signal pattern on the LCD Controller ports is defined already to empower driving without contention and work in order to not harm the LCD.

LCD Drivers / Controller also consists of characters stored in a different language to enable driving the display efficient. They also come with programmable shape memory such that they can offer user-defined characters. The manufacturer of the driver/controller will generally offer a generic software driver to provide interfacing with the device. They usually provide regulation of voltage for changing the port waveform amplitude, managing the contrast and adapt to several ambient temperatures. They also come with the inbuilt functionality to manage backlighting.

Though a short one but this was all we have regarding LCD drivers. Hope you liked going through it. Brands that manufacture them are Texas Instruments, NXP and Maxim. Make sure to follow them using the links as provided.

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Motor drives refer to those circuits that help in running a motor. It can be said in other words that they help in motor interfacing. The motor can be easily interfaced with the drives. Their selection totally depends upon the kind of motor being utilized as well as their ratings (like the voltage, current, etc.). 

Let’s take a reference of a DC motor and understand its major components.

The major components of motor drive present in DC motors are a Motor Driver IC, a controller, Power Supply Unit, DC motor and required connections to the motor.

• Controller – The controller can be a microcontroller or a microprocessor.
• Motor Driver IC – Motor Driver IC (or Motor Driver Circuits) are current amplifiers which convert low current signal taking from the controller to high current signals.
• Motor – Motor is referred to as a mechanic or electric device that can cause motion. Some motors like a stepper motor, brushless DC motor, and normal DC motor might need a driver circuit or a driver IC while interfacing with the controller. DC motor is referred to as that kind of motor that helps in converting DC into Mechanical power. The brushless DC motor consists of an inverter that produces an AC signal to drive the motor and a DC power source. Stepper motor is referred to as a brushless DC electric motor that helps in converting electrical pulses into discrete mechanical motions.
• Power Supply Unit – Offers the needed power to the motor drive.

DC Motor Driver Circuits

Motor Driver circuits are basically current amplifiers. These motor drivers behave like a bridge between the motor and the controller. Motor drivers are produced using discrete parts which are coordinated inside an IC. The motor driver circuit or a motor driver IC takes in a low current signal as an input. The main functionality of the IC is to convert this Low Current signal to a High Current signal which is then provided to the motor. The motor can be a brushed DC motor, brushless DC motor, stepper motor or other DC motors, etc.

Characteristics:

• Better performance
• Supports with the high current drive
• Gives a high level of functionality
• Offers High voltage
• It comes with an assurance scheme to avert the disappointment of motors because of any issues.

What is the need for Motor Driver Circuits (ICs)

While interfacing the motor with the controller, one of the basic needs for the controller's operation is a small amount of current with a low voltage. But the motor needs a high current and voltage for its own operation. Thus we can say that the output generated from the processor or controller is not much to drive a motor. In this case, direct interfacing of controllers to the motor is beyond the realm of imagination and we use a Motor Driver IC.

This was all we have regarding Motor Drives. Hope you liked it. Brands that manufacture them are Schneider, Omron, and Applied Motion. Make sure to follow them using the links as provided.

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The act of sensing the absence or the presence of a substance (object) with a non-contact or contact sensing device is known as presence sensing. The sensors generate an output signal (electrical) that can be utilized to control processes or equipment.

Limit switches are a category of sensing device that helps in detecting the presence and absence of objects. Mechanical limit switches refer to those switches that can be activated mechanically i.e. they consist of some kind of lever, arm, plunger, knob, etc. which is mechanically or physically activated. Other kinds of switches/sensors include light sensors, proximity sensors, etc.

As said earlier, these limit switches help in the sensing of objects in industrial applications. The device is named as 'limit switch' due to the operation it performs. As the target (object) comes in close contact with the switch’s operator, it moves the actuator to the limit where the electrical contacts change state. Because of this mechanical activity, the electrical contacts are either closed (in an open circuit) or opened (in a closed circuit). Capacitive proximity, photoelectric sensors, and inductive proximity carry out this same procedure through non-contact detection.

Let's have a look at some of the basic functions linked with limit switches.

• Counting
• Detecting Speed
• Detecting Absence or Presence
• Detecting Travel limit and Positioning
• Detecting Range of Movement
• When an unsafe condition forms up it breaks the live circuit.

Limit switches have found its use in many commercial and industrial applications which requires safety. Let’s check out some of its strengths as well as its weaknesses.

Strengths

• Limit switches can withstand several environments.
• It provides high accuracy, repeatability, and precision.
• It’s quite a good economic sensing solution.
• It’s not a big deal to switch high currents (approx. 10A).

Weaknesses

• The mechanical component used in it may wear out.
• It needs to make physical contact with an object to actuate.

Advantages of using Limit Switches

• It can operate multiple loads.
• It consumes less electrical energy.
• It can be utilized in nearly any industrial habitat.
• Loads can be switched with high inductance.
• It’s very much specific regarding repeatability and accuracy.

Disadvantages of Limit Switches

• These switches are by and large confined to hardware working at moderately low speeds.

Basic Limit Switch Design and Terminology

• Pretravel – It is the angle or the distance that the actuator must go through to trip the contacts.
• Operating Point – It is the position of the actuator where the contact break to the position of operation.
• Release point – It is the position of the actuator at which the contacts come back to their initial state.
• Differential – It is the length between contacts reset and contacts trip.
• Overtravel – It is the movement of the actuator past the contacts trip point.
• Initial Position – It is the position of the actuator when no external force is applied to it.
• Operating Force (Torque) – It is the amount of force needed to move the actuating element.

This was all we have regarding limit switches. Brands that manufacture them are Omron, Honeywell, and QUADRANT. Make sure to follow them using the links as provided.

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An SSR or a Solid State Relay is a piece of electronic switching equipment which when applied by a small external voltage across its control terminal switches ON and OFF. SSRs have a sensor in them that reacts to a proper control signal (input), a piece of switching equipment that changes power to the load circuit, and a coupling process to empower the control signal to initiate this switch without the help of any mechanical parts. The relay might be made to switch either DC or AC to the load. It offers the same functionality as that of an electromechanical relay but comes with no moving parts.

Packaged Solid State Relay utilizes power semiconductors like transistors and thyristors to change the electrical current approximately to hundred Amperes. The switching speed of solid-state relays is comparatively faster than that of the electromechanical relays. In addition to that, it has no physical contacts to wear out. The devices using the Solid State Relays must take into consideration their higher value of “ON” state resistance as well as their lower capacity to hold out against momentary overload. In contrast to an electrochemical relay, the SSR offers only a limited amount of switching arrangement.

Operation

A Solid State Relay that works based on a particular MOSFET (or multiple ones in a parallel array) works well with DC loads. This MOSFET comes with a substrate diode which helps in the conduction of electricity in the reverse direction. Thus it is not possible for a particular MOSFET to stop the current in both directions. To carry out an AC operation, 2 MOSFET are positioned one after the other with their source pins integrated. The output side is connected with their drain pins. The substrate diodes are reverse biased alternately such that the current can be blocked whenever the relay is OFF. Whenever the relay is ON both the gates are positively biased comparative with the source by the photograph diode.

Parameters

Solid State Relay is governed by several parameters. They are:

• Required activating output current and voltage
• Required activating input current and voltage
• AC or DC
• Resistance or potential drop affecting the output current and thermal resistance.
• SSRs are much less sensitive to operating environment and storage factors like humidity, mechanical shock, external magnetic fields, and vibration.

Advantages of SSR over Mechanical Relays:

• Slimmer and smaller than a mechanical relay.
• It carries out a totally silent operation.
• The switching speed of SSRs is much faster than that of electromechanical relays.
• The output resistance does not vary regardless of the amount it is utilized.
• The operation is bounceless and clean.

Disadvantages:

• For the gate charged circuit an isolated bias supply is needed.
• There is a chance of false switching because of the voltage’s momentary variations.

Hope you liked going through the article on Solid State Relay. Brands that make SSRs are Crydom, Omron and Phoenix Contact. Make sure to follow them using the links as provided here. Thank you for reading.

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A switch that can be operated electrically is known as a relay. It consists of several operating contact terminals as well as a group of input terminals for multiple or single control signals. The switch might come with a different number of contacts in several contact forms, like break contacts, make contacts, etc.

Relays have found its uses at places where several circuits need to be controlled by a particular signal or where it is important to control the circuit by a low power signal which is independent. Firstly relays were utilized as signal repeaters in long-distance telegraph circuits. Here they used to revive the signal rolling in from one circuit by broadcasting it on another circuit. Relays were utilized excessively in early computers as well as telephone exchanges to carry out logical operations.

The basic version of relays takes the help of an electromagnet to open or close the contacts, however, other working standards have been concocted like the solid-state relays which utilize the semiconductor properties for controlling. Relays that comes with multiple operating coils and adjusted working attributes are utilized in protecting electrical circuits from faults and overload. In current electric power frameworks, these capabilities are taken care of by digital instruments known as protective relays.

Types of Industrial Relay

• Coaxial Relay – Whenever a single antenna is shared between a radio receiver and a transmitter, coaxial relays are used. It helps in switching the antenna from the receiver to the transmitter. Thus the receiver is defended from transmitter's high power.

• Contactor – A heavy-duty relay that comes with a high current rating which is utilized for switching lighting loads and electric motors is known as a contactor.

• Force-guided contacts relay - These types of relay come with contacts that are linked together mechanically such that whenever the relay coil gets energized or de-energized, all of them moves together.

• Latching Relay – A latching relay is basically an electromechanical switch that helps in controlling small flow of electrical current with a larger flow of current.

• Machine tool relay - A machine tool relay is a relay that is used mainly for industrial control of transfer machines, machine tools, etc.

• Mercury Relay – The relay that takes the help of mercury as a switching element is known as mercury relay.

• Multi-Voltage relay – These relays are made in such a manner that they can withstand a wide range of frequency (0 to 300 Hz) as well as a wide range of voltage (24 to 240 VAC).

• Polarized relay – This relay positions the armature in between the poles of a permanent magnet only with a motive to increase sensitivity.

• Static Relay – This kind of relay comes with electronic circuitry to imitate each one of those attributes which are accomplished by moving parts in an electromagnetic relay.

This was all we have regarding Industrial Relays. Hope you enjoyed going through it. Brands that manufacture them are Phoenix Contact, TE Connectivity, and Omron. Make sure to visit them from the links as provided.