Category Archives: Electronic Products

PTC Thermistors: Positive Temperature Coefficient

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The positive temperature coefficient, PTC thermistor has two types: silistor & switching PTC have very different characteristics.

 

As the name indicates a positive temperature coefficient, PTC thermistor has a response in which the resistance rises with increasing temperature.

 

There are two types of PTC thermistor which have very different characteristics, one showing a linear increase, whilst the other shows a sudden change in resistance.

 

PTC thermistor outline

 

PTC thermistors can be divided into two types according to their structure and the materials used. The two types of PTC thermistor have very different characteristics:

 

  • Switching PTC thermistor:

This form of PTC thermistor is used in heaters, sensors and specialized versions are also used as resettable fuses. Switching type NTC thermistors have a highly non-linear curve. The resistance at first falls slightly with increasing temperature, and then at a critical temperature the resistance increases dramatically, thereby acting virtually as a switch. This makes it ideal in many protection devices.

  • Silistor:

The silistor PTC thermistor uses a semiconductor as its base material and it is characterized by a linear characteristic and as a result, the silistor is used in temperature sensors. The silistor PTC thermistor is generally manufactured from doped silicon, the level of doping determining the exact characteristics.

 

Switching PTC thermistor basics

 

As the switching PTC thermistor is very widely used form, it warrants further explanation as it has an unusual characteristic.

 

Switching PTC thermistors are typically fabricated from polycrystalline materials including barium carbonate or titanium oxide with added materials including tantalum, silica, or manganese, etc.

 

The materials are mixed and ground to fine powders and finally compressed into the required shapes before being sintered. Contacts are then added and the thermistor is encapsulated.

 

The characteristic of the switching PTC thermistor shows that the device has a highly non-linear characteristic. As the temperature increases, the resistance first decreases, then rising slightly before it reaches a critical temperature, TC. At the critical temperature the resistance increases sharply for any increase in temperature, before finally leveling off and falling slightly.

 

A similar type of device is known as a Polymer PTC. These devices consist of a plastic element into which carbon grains are embedded. When cool, the carbon is able to conduct electricity, but as the temperature increase the carbon grains move further away as a result of expansion and conduction falls rapidly. In this way the device acts like a switch in the same way as the more traditional PTC thermistors.

 

PTC thermistor operational modes

 

There are two main ways in which switching PTC thermistors are generally used.

 

  • Self-heating mode:

When used in the self-heating mode, current is passed through the thermistor, often in series with the item being controlled. As it heats up as a result of the current, it reaches a point where the critical temperature is reached and the resistance increases significantly. In this way it operates in a self-heating mode and can be used as a safety cut-out or regulator.

 

  • Sensor mode:

In this mode, a minimum amount of current is passed through the device and PTC thermistor senses the surrounding temperature. Keeping the current to a minimum ensures the self-heating effect is negligible and only the surrounding temperature affects the device. As the surroundings heat the device it may reach its critical temperature at which point the resistance will significantly increase.

 

Switching PTC thermistor applications

 

Switching thermistors are a very useful form of electronic component. It can perform functions with a single component that would require far more complex circuitry should any other technique be used.

 

  • In-rush protection:

Some electrical items like motors and transformers have a large surge of current at switch on. This gives rise to very high peaks of current which can cause spikes on the power line, or cause damage in some instances. PTC thermistors can be used to reduce the level of the inrush current and thereby prevent the spikes or damage occurring.

 

  • Overcurrent protection:

In this application, the PTC thermistor is placed in series with the load and uses the self-heating effect. The current taken under normal conditions should enable the thermistor to operate in its flat resistance curve area. However if an over-current condition arises, then the thermistor will carry more current and the temperature will rise more causing it to rise beyond the critical temperature when the resistance will rise significantly causing the current to drop.

 

PTC thermistor circuit symbol

 

It is sometimes necessary to indicate the type of thermistor being used on a circuit diagram. Accordingly the IEC have a special PTC thermistor circuit symbol that can be used.

 

As seen the circuit symbol utilizes the characters +t° to give an indication of the positive temperature coefficient.

 

Positive temperature coefficient, PTC thermistors are used in many electronic circuits and for a variety of functions. It is essential to check that the correct type is selected for any given circuit to ensure that its characteristic meets the requirements.

 

Zonkas is the experienced and reliable manufacturer of specializing in capacitor, inductor, and transformer. If you are still interested in PTC thermistors, welcome to visit the website of Zonkas.

 

 

Article Source: https://www.electronics-notes.com/articles/electronic_components/resistors/thermistor-ptc-positive-temperature-coefficient.php

Scope Of RFID Systems In Security Measures

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What is RFID?

 

Radio-frequency identification device is a technology that retrieves the status and presence of a thing to which it is attached to remotely. These devices will track the objects automatically and sends the embedded information to the processors.

 

Typical components of RFID system

 

An RFID system contains an RFID tag, RFID reader, RFID antenna, and RFID package.

 

RFID tag is attached to the item that needs to be tracked and identified.

 

RFID antenna will detect the RFID tag when it comes in range.

 

RFID reader reads the RFID tags and authenticates its presence.

 

RFID package contains the server and software and transmits the information to all other applications.

 

Application of RFID systems

 

To simplify, RFID systems do the same function as of a BAR-CODES, but when it comes to applications they are widely spread as RFID systems doesn’t need to maintain contact with the scanners as in case of BAR-CODE. High Frequency RFID systems doesn’t necessarily to be appear in the line of sight, especially such are applied for livestock tracking, Missile tracking, automobile tracking through assembly lines and most importantly in case of vehicle tracking.

 

Security potential

 

Increasing security measures through CCTV cameras has already outdated, the latest technology implies to the usage of RFID readers wherever the security is needed along with authentication.

 

They can be installed in a library, home, and elsewhere domestically to secure the important files, books, and expensive things, so that even when they are found missing they can be easily detected with the help of local servers that are giving location information.

 

They can also be placed in a vehicle, thanks to their non-contact readable characteristic feature as the vehicles can be tracked along the route as they can use the location provided by the nearest GSM signal boosting towers and thus one can keep notice of their vehicles.

 

The size of the smallest developed RFID is 0.05mm × 0.05mm size and the average size would be around 3mm x 3mm. As we go cheaper the size will be increased consistently. Their dimensions make them invisible to see which a plus point in terms of security measures is.

 

Evercom Communication Technology Co., Ltd. is the professional company of specializing in kinds of antennas. If you are interested in learning more details about RFID antenna and other antennas, welcome to visit Evercom’s website to see what antennas they can offer you.

 

 

Article Source: http://EzineArticles.com/8431202

What Is a Proximity Reader?

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If you are in the process of updating your home’s or business’s security system or if you never had such a system and you are planning to invest in one, there are probably a lot of industry terms you don’t understand very well. That is why, in this article, we are going to talk about two important parts of any security access system, the proximity card and the proximity reader.

 

Proximity cards, also referred to as prox cards, are different than the magnetic stripe cards, because they do not need to be inserted into the reader device to grant access in the secured area. We say “grant access” because the majority of proximity cards and proximity readers are used as a part of home or business security system. Other uses include library cards, contactless payment systems or in public transit fare. Proximity cards are practical due to the fact that they can easily be read through a wallet or a purse.

 

There are two main types of proximity cards: passive and active. Passive prox cards have a limited range and are widely used to grant access in office buildings. Active cards, also called vicinity cards, have a greater range (150 meters), due to the fact that they use and internal lithium battery. They can be used to easily access courtyards from inside of a vehicle or from automated toll collection.

 

Now, in case you were wondering “What is a Proximity Reader?” they are devices that can store details about the identity of the cards holders, granting them access to otherwise restricted areas. This system is similar to the “chip and PIN” bank cards, with the difference that the proximity reader grants access using radio frequencies and does not need actual insertion of the card. Also, they offer more security to their holders, due to the fact that they are harder to copy. Another great advantage of these readers is the fact that they are quite sturdy and do not need any maintenance.

 

Another term you might encounter when browsing for this type of access system in “Contactless Smart Card”, which is basically the same thing, with the difference that they use advanced methods of data encryption and authentication, meaning that they offer a higher level of security. Besides this general information, there are various technologies that are used in the manufacture of proximity cards and readers.

 

If you are planning to invest in such a system, you must know that the prices are very different from one product to another. For example, the price for a single card ranges from $2 to $200, while for the proximity reader you can pay from $100 to $400.

 

Before making any purchase, we advise you to ask the advice of an experienced security technician, just to make sure that you choose the right system for your needs. The good news is that the majority of shops, even online ones, have an assistant which can help you make the right decision.

 

Pongee Industries Co., Ltd. is the manufacturer of proximity reader. If you are looking for the best proximity reader, don’t miss Pongee’s website, we can offer clients kinds of high quality products. Contact with Pongee to obtain further product information!

 

 

Article Source: http://EzineArticles.com/8665232

Difference between Manual Thermostats and Electrical Thermostats

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A thermostat is a temperature–sensitive device that turns HVAC systems on and off when the temperature of an environment reaches a preset level. Essentially, it turns on the air conditioning when it gets too warm, or the heating when it gets too chilly. Thermostats control the workings of comfort systems by directing energy to the appropriate system when needed. When selecting a thermostat, property owners can either go for simple manual thermostats or sophisticated electronic thermostats that provide improved functionality and highly efficient operations. Thanks to the easy to understand packaging and universal compatibility, choosing a thermostat is easy.

 

Systems that Use a Thermostat

Single–stage heating systems have one electrical or gas heating device, which may consist of a heater or an AC device as well. Most units that use natural gas provide single–stage heating. Usually, a single–stage thermostat should have room for three wires if the system handles heating only. However, if the system handles heating and cooling, the thermostat will have to accommodate five wires or less.

 

Multi–stage systems have a standard electrical or gas heating device as well as an emergency and/or auxiliary heating device. The emergency or auxiliary heating kicks in when temperatures drop faster than the standard heater can handle, or if the standard heater fails. Line voltage systems, on the other hand, use direct current. Homeowners should choose line voltage thermostats that can handle additional conducted power.

 

Difference between Manual and Programmable Electrical Thermostats

 

Electromechanical or annual thermostats are the traditional mercury units that have internal coils to contract and expand in response to changes in temperature. They are becoming obsolete because of two main reasons:

 

  • Products containing mercury are banned or restricted in most states
  • Programmable thermostats are more accurate and sensitive to temperature changes

 

However, manual thermostats are still popular due to their ease of use, low cost, and the familiarity of their controls.

 

Digital manual thermostats use an electronic sensor to register temperature changes in an environment and then compare those changes to the preset settings. If there is a difference, the thermostat sends a warning to the cooling or heating system that immediate action is required. However, users still have to physically adjust the settings to their preferred level.

 

Programmable electrical thermostats are an upgrade from the manual thermostats. In addition to saving energy costs, they allow homeowners to program their preferred temperature settings into the unit’s memory, along with the time of day they would like the changes to occur.

 

For most homes, a pre–programmed electrical thermostat does not need any adjustment. Homeowners simply need to install it and they are ready. When determining the right thermostat, homeowners should consider the flexibility and functionality they need from day to day.

 

Alpha Brass electrical thermostats are manufactured and calibrated with precision to provide accurate temperature points. These thermostats are snap-acting and the temperature is controlled by signal interrupting the gas flow to the burner. If you need further details about our electrical thermostats, welcome to browse our website or contact with Alpha Brass directly!

 

 

Article Source: http://cphac.com/blog/difference-manual-thermostats-electrical-thermostats

SMPS: Basics & Working of Switched Mode Power Supply

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Switching mode power supply (SMPS) is used in a range of applications as an efficient and effective source of power. This is in major part to their efficiency. For anybody still working on a desktop, look for the fan output in the central processing units (CPU). That’s where the SMPS is. SMPS offers advantages in terms of size, weight, cost, efficiency and overall performance. These have become an accepted part of electronic gadgets. Basically it is a device in which energy conversion and regulation is provided by power semiconductors that are continuously switching “on” and “off” with high frequency.

 

The different kinds

  • C. to D.C. Converter
  • Forward Converter:
  • Flyback Converter:
  • Self-Oscillating Flyback Converter
  • DC-DC converter

 

The primary power received from AC main is rectified and filtered as high voltage DC. It is then switched at a huge rate of speed and fed to the primary side of the step-down transformer. The step-down transformer is only a fraction of the size of a comparable 50 Hz unit thus relieving the size and weight problems. We have the filtered and rectified output at the secondary side of the transformer. It is now sent to the output of the power supply. A sample of this output is sent back to the switch to control the output voltage.

 

Forward converter

 

In a forward converter the choke carries the current when the transistor is conducting as well as when it’s not. The diode carries the current during the OFF period of the transistor. Therefore, energy flows into the load during both the periods. The choke stores energy during the ON period and also passes some energy into the output load.

 

Flyback converter

 

In a flyback converter, the magnetic field of the inductor stores energy during the ON period of the switch. The energy is emptied into the output voltage circuit when the switch is in the open state. The duty cycle determines the output voltage.

 

Self-Oscillating Flyback Converter

 

This is the most simple and basic converter based on the flyback principle. During the conduction time of the switching transistor, the current through the transformer primary starts ramping up linearly with the slope equal to Vin/Lp. The voltage induced in the secondary winding and the feedback winding make the fast recovery rectifier reverse biased and hold the conducting transistor ON. When the primary current reaches a peak value Ip, where the core begins to saturate, the current tends to rise very sharply. This sharp rise in current cannot be supported by the fixed base drive provided by the feedback winding. As a result, the switching begins to come out of saturation.

 

Basic working concept of a SMPS

 

A switching regulator does the regulation in the SMPS. A series switching element turns the current supply to a smoothing capacitor on and off. The voltage on the capacitor controls the time the series element is turned. The continuous switching of the capacitor maintains the voltage at the required level.

 

Design basics

 

AC power first passes through fuses and a line filter. Then it is rectified by a full-wave bridge rectifier. The rectified voltage is next applied to the power factor correction (PFC) pre-regulator followed by the downstream DC-DC converter(s). Most computers and small appliances use International Electrotechnical Commission (IEC) style input connector. As for output connectors and pinouts, except for some industries, such as PC and compact PCI, in general they are not standardized and are left up to the manufacturer.

 

Why SMPS

 

Like every electronic gadget, switching mode power supplies also involve some active and some passive components. And like every of those gadgets, it has its own advantages and disadvantages.

 

Let’s start with why you should go for a SMPS

 

  • The switching action means the series regulator element is either on or off. Very high efficiency levels are achieved as very little energy us dissipated as heat.
  • As a result of the high efficiency and low levels of heat dissipation, the switch mode power supplies can be compact.
  • Switch mode power supply technology also provide high efficiency voltage conversions in voltage step up or “Boost” applications and step down or “Buck” applications.

 

Then there’s the bad set

 

  • The transient spikes due to the switching action can migrate into other areas of the circuits if not properly filtered. These can cause electromagnetic or RF interference affecting other nearby items of electronic equipment, particularly if they receive radio signals.
  • To ensure that a SMPS performs as per the required specification can be a bit difficult. The ripple and interference levels are particularly tricky.
  • The costs of a switch mode power supply is calculates before designing or using one. Additional filtering further adds to the cost.

 

What would the future hold?

 

In the future, we could have more efficient SMPS aimed at a better converter doing the most effective conversion process. The focus areas for designers in making SMPS efficient would be:

 

  • Higher output power
  • Achieving higher current output and low voltage
  • Increasing power density
  • Using switching device like Schottky diode

 

Hon-Kwang Electric specialized in manufacturing switch mode power supply and related products. We provide series of switching power supplies to meet different demands of you. If you are interested in learning more details about switching mode power supply, please feel free to contact with Hon-Kwang.

 

Article Source: http://electronicsforu.com/resources/learn-electronics/smps-basics-switched-mode-power-supply

Choosing the Best Option for Overcurrent Circuit Protection

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When it comes to overcurrent protection of electronic equipment, fuses have long been the standard solution. They come in a wide variety of ratings and mounting styles to fit virtually any application. When they open, they completely stop the flow of electricity, which may be the desired reaction; the equipment or circuit is rendered inoperable, which draws the user’s attention to what may have caused the overload condition so that corrective action can be taken.

 

Nevertheless, there are circumstances and circuits where auto-recovery from a temporary overload without user intervention is desirable. Positive temperature coefficient (PTC) thermistors – also called polymeric positive temperature coefficient devices (PPTCs) or resettable fuses – are an excellent way of achieving this type of protection.

 

Ceramic PTCs are also widely available through possess different operating characteristics including greater internal resistance, higher ambient heat tolerance, and higher voltage ratings. As they are typically used within high ambient heat areas including heating equipment applications not common to many electronics requirements, they were not factored within the scope of this article.

 

How a PTC works

 

A PTC resettable fuse consists of a piece of polymer material loaded with conductive particles (usually carbon black). At room temperature the polymer is in a semi-crystalline state and the conductive particles touch each other, forming multiple conductive paths and providing low resistance (generally about twice that of a fuse of the same rating).

 

When current passes through the PTC it dissipates power (P = I2R) and its temperature increases. As long as the current is less than its rated Hold Current, IHOLD, the PTC resettable fuse will remain in a low-resistance state and the circuit will operate normally. When the current exceeds the rated Trip Current, ITRIP, the PTC heats up suddenly. The polymer changes to an amorphous state and expands, breaking the connections between the conductive particles. This causes the resistance to increase rapidly by several orders of magnitude and reduces the current to a low (leakage) value just sufficient to keep the PTC in the high-resistance state – generally from around tens of milliamps to several hundred milliamps at rated voltage (Vmax). When the power is shut off the device cools down and returns to its low-resistance state.

 

Like a fuse, a PTC is rated for the maximum short circuit current (IMAX) it can interrupt at rated voltage. IMAX for a typical PTC is 40A, and may reach 100A. Interrupting ratings for fuses of the sizes that may be used in the sorts of applications we are considering here can range from 35 to 10000 amperes at rated voltage.

 

The voltage rating for a PTC is limited. PTC resettable fuses for general use are not rated above 60V operating voltage (there are PTCs for telecom application with 250V and 600V interrupting voltage, but their operating voltage is still 60V); surface-mount and small cartridge fuses are available with ratings from 32V to 250V or more.

 

The operating current rating for PTCs ranges up to about 9A, while the maximum level for fuses of the types considered here can exceed 20A, with some available to 60A.

 

The useful upper temperature limit for a PTC is generally 85°C, while the maximum operating temperature for thin-film surface mount fuses is 90°C, and for small cartridge fuses is 125°C. Both PTCs and fuses require derating for temperatures above 20°C, although PTCs are more sensitive to temperature (Fig.2). When designing in any overcurrent protective device, be sure to consider factors that may affect its operating temperature, including the effect on heat removal of leads/traces, any air flow, and proximity to heat sources. The speed of response for a PTC is similar to that of a time delay fuse.

 

Common PTC applications

 

Much of the design work for personal computers and peripheral devices is strongly influenced by the Microsoft and Intel System Design Guide which states that “Using a fuse that must be replaced each time an overcurrent condition occurs is unacceptable.” And the SCSI (Small Computer Systems Interface) Standard for this large market includes a statement that “… a positive temperature coefficient device must be used instead of a fuse, to limit the maximum amount of current sourced.”

 

PTC resettable fuses are used to provide secondary overcurrent protection for telephone central office equipment and customer premises equipment, alarm systems, set top boxes, voice over IP (VOIP) equipment and subscriber line interface circuits (SLICs). They provide primary protection for battery packs, battery chargers, automotive door locks, USB ports, loudspeakers and power over Ethernet.

 

SCSI Plug and Play applications that benefit from PTCs include both the mother-board and the many peripherals that can be frequently connected to and disconnected from the computer ports. The mouse, keyboard, printer, modem and monitor ports represent opportunities for misconnections and connections of faulty units or damaged cable. The ability to reset after correction of the fault is particularly attractive.

 

A PTC resettable fuse can protect disk drives from the potentially damaging overcurrent resulting from excessive current from a power supply malfunction.

 

PTC resettable fuses can protect power supplies against overloading; individual PTCs can be placed in the output circuits to protect each load where there are multiple loads or circuits.

 

Motor overcurrent can produce excessive heat that may damage the winding insulation and for small motors may even cause a failure of the very small diameter wire windings. The PTC will generally not trip under normal motor start up currents, but will act to prevent a sustained overload from causing damage.

 

Transformers can be damaged by overcurrent caused by circuit faults, and the current limiting function of a PTC can provide protection. The PTC is located on the load side of the transformer.

 

Fuse or PTC?

 

The following procedure will help in selecting and applying the correct component. Help is also available from device suppliers. For unbiased advice it is wise to look for a company that offers both fuse and PTC technology.

 

  1. Define the circuit operating parameters. Consider the following: normal operating; current in ampere; normal operating voltage in volts; maximum interrupt current; ambient temperature/rerating; typical overload current; required opening time at specific overload; transient pulses expected; resettable or one-time; agency approvals; mounting type/form factor; typical resistance (in circuit).

 

  1. Select a prospective circuit protection component.

 

  1. Determine the opening time at fault. Consult the Time-Current (T-C) Curve to determine if the selected part will operate within the constraints of the application.

 

  1. Verify ambient operating parameters. Ensure that the application voltage is less than or equal to the device’s rated voltage and that the operating temperature limits are within those specified by the device

 

  1. Verify the device’s dimensions. Compare the maximum dimensions of the device to the space available in the application.

 

  1. Test the selected product. Independently test and evaluate suitability and performance in the actual application.

 

Zonkas is the professional manufacturer of capacitor, inductor and transformer. Our main products including: various inductors, transformers, Safety Capacitor (Y1, Y2, X1, X2), Ceramic Capacitor, Film Capacitor and Electrolytic Capacitor. If you need more information about PTC resettable fuses or other capacitors, welcome to visit our website or contact with Zonkas directly!

 

 

Article Source: http://www.engineerlive.com/content/21341

Multiple Connectivity Modes with Biometric Access Control

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Biometric Access Control is the new age technology that has revolutionized attendance and access systems like never before. The age of swapping cards and proxy punching is long gone and now all organizations are adopting this new technology which uses various human traits such as fingerprint scanning, retina scanning and facial recognition in place of swapping cards and passwords. The benefit of these human traits is that they are unique to every individual and cannot be duplicated or stolen.

 

Every year organizations lose a huge sum of money due to time thefts and unnecessary manual work of calculating wages and working days of each and every employee. This is not only tiresome and time consuming but also costs a lot of money. No organization can afford such costs in this highly competitive world. So many organizations are now switching to biometric scanning processes which enable them to save money and also time.

 

Biometric technology has various modes of connectivity and access depending on the needs and want of any organization. Manufacturers of these scanners keep the needs of the customers in mind and provide them with customized technologies most compatible with their employees and their requirements. The different modes include fingerprint scanning, which include the scanning of fingerprints of every employee while entering or leaving the office. Retina scanning is the process by which the iris, retina and other features of the human eye are scanned and then admission is allowed to any individual inside any high secure facility. Retina scanners are really very accurate and personalized. Many high risk government and private facilities use a combination of fingerprint scanning and retina scanning in order to provide maximum security and to ensure that only authorized personnel are allowed to enter. Facial recognition includes scanning the vital points of any individuals’ face that differentiate it from any other individual.

 

Thus latest biometric technology is the technology of the next age and many organizations have already started using it. Preliminary results have been very promising and many are inclined to follow the trend in near future. Its products are very reliable. These biometric systems are now available easily and you can access them as per your convenience and requirements. So don’t be late and order a biometric scanner as per your requirements as soon as possible. It’s high time to upgrade yourself if you don’t want to lag behind in this competitive world.

 

Quality biometric access control system manufacturer – Pongee, providing fingerprint time attendance, face recognition access controller and USB fingerprint scanner in this series. Our biometric access controllers with time recorders are high security, easy to start and easy to use. Welcome to browse the specification about our biometric access control systems and feel free to contact with Pongee for more details!

 

 

Article Source: http://EzineArticles.com/9011041

 

LCD Video Wall Systems for Modern Control Rooms

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The best display technologies of only 10 years ago are considered primitive by today’s standards. They were a poor return on investment because they were expensive and added little to the control room’s comparative ability to manage critical information. Expensive large format front and rear projectors were the primary choice. They were undependable, relatively low resolution, and required expensive maintenance contracts because they rarely had redundancy when a projection lamp failed. Then you add expensive, bulky hard-wire switchers to bring signals to the projectors and you still don’t have the capabilities of today’s most basic LCD video wall driven by a computerized controller. In fact, much of what was considered state of the art at the time was just “eye candy”; it looked good, but did little to advance the performance of the people using it.

 

What is considered a modern video wall system?

It employs a matrix of displays driven by a sophisticated computer that allows the operator to acquire and display more information faster than with older methods. This also means faster and better decision making. These are the type display systems that do much more than merely connect a switch between computers and individual displays mounted to the wall. These systems allow you to reach out on the data network and bring in an almost unlimited number of sources to the video wall, and as the network grows, it is unaffected except to say that more screen surface could be needed to display more information than before.

 

The growing popularity of LCD video wall systems

These are now more popular because they meet most performance requirements, require less investment and occupy the least amount of floor space. In fact they can be mounted on the wall taking up only 4-6″ in depth. These high resolution displays form a matrix or single pallet. Each display’s ultra-thin bezel is designed to minimize distraction when enlarging images across multiple displays.

 

These are relatively easy to install and require little maintenance or adjustment. They are rarely repaired because it’s easier and faster to replace than repair, however the typical industrial LCD display will run dependably for thousands of hours.

 

I should point out that these systems perform the same as video walls with other type displays because it’s the video wall controller, or brain of the system that acquires and displays what is shown on the video wall. The video controller (processor) doesn’t see the number of displays, or the type or size of displays. The controller sees the matrix of displays as a single display allowing the images to be easily placed and sized anywhere on the overall screen surface.

 

There are two types of LCD video wall used in control rooms; wall mounted or freestanding cabinet. Wall mounted systems require that the wall be reinforced and cannot be installed or easily relocated like a 12″ deep cabinet. The cabinet is modular and stores all supporting electronics in the base and as a result, can be easily expanded and relocated as requirements change.

 

For more information on this, please ask advice from an experienced LCD video wall solution provider like EAGO Vision, the company specializes in customizing LCDs monitors and troubleshooting electronic devices related issues. Welcome to visit the website of EAGO and feel free to contact with us.

 

 

Article Source: http://EzineArticles.com/8416914

 

Professional Low Voltage Power Capacitors Manufacturer – YUHCHANG

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YUHCHANG Electric is a professional capacitors manufacturer with almost 60 years’ experience. Since, establishment, we emphasize the technical development, completeness of service and product quality. Nowadays we have up-to-date production technology and been acquired ISO 9001:2000 and ISO 9002 for capacitors. Our low voltage power capacitors main include two types: Oil-Type and Gas-Filled Dry-Type.

 

Oil type

Oil type low voltage power capacitors use metal case. Capacitor elements are impregnated in high vacuum, low temperature rise, thus they have long life expectancy and can be operated at high ambient temperature. Some other features as following:

 

  • Self-healing mechanism, low dissipation factor, low temperature rise, long service life.
  • Good electrical characteristic, the best heat dissipation, and long service life; particularly suited for use in filter circuit.
  • Safety: Internal protective device to prevent capacitor from bursting and avoid the relative disaster.
  • Use environment friendly insulation oil (non-PCB).

 

Dry-Type

C-series dry-type low voltage power capacitor uses aluminum can having compact volume, anti-fire and against climate change character. This is the best design for saving space and cost down. There are following merits:

 

  • Dry-Type, N2 (nitrogen) filling, and non-pollution of environment friendly products.
  • Safety: Self-healing mechanism, internal protective device (Overpressure tear-off fuse) with overload and failure protection for every phase.
  • Against electric shock terminals, easy connection.
  • Low dissipation factor, low temperature rise, long service life.
  • The bottom of the can has a mounting stud for mounting and earthing at the same time, easy for installation.

 

Application

 

The improvement of Power Factor in low voltage power system, or use in power filter circuits.

 

If you need more information about power capacitors, welcome to visit the website of YUHCHANG – superior quality of high voltage power capacitors and low voltage power capacitors can be manufactured by YUHCHANG power capacitor manufacturer.

 

 

YUHCHANG Electric Co., Ltd.

No.59, Chung Cheng St., Ching Shui Dist., Taichung City 43653, Taiwan (R.O.C.)

TEL: (04)2622-4188

FAX: (04)2622-4646

E-mail: yce919@ms1.hinet.net

What is a GPS Antenna?

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A GPS antenna is a device that helps boost the reception signal to a GPS unit, whether it is a standalone unit or an embedded unit. Often a GPS antenna is used in a situation where the GPS unit itself is somehow removed from a line of sight to the sky, as in a car, to help the GPS “see” the sky without having to be moved. GPS antennae may be purchased for a range of budgets, or cheaper home versions can be made with fairly common components.

 

GPS, or the Global Positioning System, is a satellite system originally developed by the United States Department of Defense. It utilizes more than two dozen satellites orbiting the Earth to allow receivers on the ground or in the sky to tell exactly where they are, by receiving heads off of multiple satellites. Using this location, devices can detect not just latitude and longitude, but also altitude, and even heading and speed. For years, GPS was reserved for military use in the United States, but following a directive by President Reagan in 1983 it became open for civilian use.

 

Civilian GPS contains certain restrictions, imposed by the US government to make sure hostile forces don’t use the technology in missiles. As a result, consumer GPS isn’t capable of operating when moving at more than 515 m/s at more than 60,000 feet (18 km). Throughout the eighties and early nineties GPS was used primarily in commercial avenues, such as on fishing boats, in airplanes, or for geographic surveying. In the late nineties it began gaining popularity for consumers for hiking or for driving, and by the new millennium cars were being equipped with built-in GPS to give driving directions, and cell phones began having included GPS for directions and location.

 

A GPS unit has a built in antenna, which is usually quite small and located inside of the unit. While this will likely function in ideal circumstances, such as when in a desert moving at slow speeds or staying still, it may not work as well as one would like in more trying circumstances. A GPS unit likes to have a clear, unobstructed view of the sky, to best receive the microwave signals that allow it to communicate with satellites. For GPS units inside of cars, this can be problematic, so often an external GPS antenna will be used, mounted to the outside of the car with a magnet, and connected to the unit itself by a cable.

 

In situations such as heavy canopy cover while hiking, the small GPS antennas built into a consumer unit also may not be able to ideally communicate with the satellites. In this case, a larger, more advanced GPS antenna helps the unit overcome the environmental challenges, to give a clear signal. Similarly, moving at high velocities can overwhelm a smaller, less sophisticated antenna, and an external device can boost the signal.

 

There are a number of different types of GPS antenna, with the patch and Quad Helix styles being the most popular. Both are roughly equal in efficacy, although many people find the quad helix to have a slight bit more sensitivity. Other types of antennae include microstrips, of which the patch is one configuration, planar rings, and spiral helices.

 

Established in 1996, Cirocomm is an outstanding manufacturer of GPS antenna in the industry. We also provide various antenna series, including dielectric filter, Glonass, WIFI, GSM, NFC antenna series and more. If you are interested in and need more details about GPS antennas, welcome to visit our website and send inquiry to Cirocomm!

 

Article Source: http://www.wisegeek.com/what-is-a-gps-antenna.htm