Tech ministry to invest NT$4 billion in IC development, aiming AI

Tech ministry to invest NT$4 billion in IC development, aiming AI

Taipei, Aug. 15 (CNA) The Ministry of Science and Technology (MOST) said Tuesday that it plans to invest NT$4 billion (US$132 million) over the next four years in the local semiconductor sector in a bid to maintain Taiwan’s global competitive edge.

Science and Technology Minister Chen Liang-gee (陳良基) told the press that the four-year plan code named the “moon shoot” has set its sights on artificial intelligence by widening the applications of Taiwan’s integrated circuit industry to meet demand.

According to the ministry, the four-year plan will kick off in 2018 as it starts to allocate NT$1 billion a year.

Chen said that with many international brands having entered AI development, it is expected to boost demand for highly efficient computing and energy-efficient ICs. As a result, Taiwan is in a strong position to take advantage of its strength in semiconductor technology to seize newly developing business opportunities.

International tech giants that have poured resources into the AI industry include Google Inc., Microsoft Corp., Apple Inc., Facebook Inc., Intel Corp., and Qualcomm Inc.

In particular, Chen said, Taiwan is good at IC design and that strength is expected to help the local semiconductor industry roll out specialty ICs for future AI applications.

Chen said that his ministry has designated 2017 the first year of AI development in Taiwan, with the four-year IC development plan expected to roll out critical IC devices for AI development by 2022.

Chen said the global semiconductor business is expected to launch commercial production of chips made using the advanced 3 nanometer process in 2022, an important transition point for AI development. In addition, the ministry’s four-year IC development plan will help Taiwan’s efforts to advance AI industry.

Currently, Taiwan Semiconductor Manufacturing Co. (TSMC, 台積電), the world’s largest contract chip maker, is focusing on developing the 3nm process, with a plan to set up a new 3nm plant.

TSMC’s latest technology to enter commercial production is the 10nm processor, while the chip maker is developing 7nm, 5nm and 3nm processes in a bid to maintain its lead over competitors in the global semiconductor market.

According to the ministry, the four-year investment plan was devised after consulting with IC giants such as TSMC, United Microelectronics Corp. (聯電) and Taiwan’s largest IC designer MediaTek Inc. (聯發科).

The ministry said funding will mainly go to the academic sector, which is expected to seek a partnership with the business community over the next four years, adding that the plan looks to cultivate a pool of talent for Taiwanese firms.

The ministry added that the four-year plan is not part of the government’s “Forward-looking Infrastructure Development Program,” which has its own budget for digital technology development.

The country will spend up to NT$420 billion on the forward-looking program over the next four years.

(By Liao Yu-yang and Frances Huang)

Laser Security Alarm Circuit

Laser Security Alarm Circuit

Security is main concern for various buildings, houses and offices. For this purpose, there are a variety of security alarms available in market which uses various types of technology for intruder detection like infrared sensors, motion sensors, ultrasonic sensors, laser sensors, etc. We have also built some security alarms like this PIR sensor based motion detector and burglar alarm circuit. In this circuit we are going to build a laser security alarm which uses a laser light and a laser light detector circuit. It gets activated when someone crosses it.

Circuit Components

  • IC LM358
  • 555 Timer IC
  • Laser light
  • 150 Ohm, 10K Resistor
  • 10 K POT
  • 220uF capacitor
  • LDR
  • Breadboard
  • 9 Volt Battery and Connector
  • LED

Circuit Diagram and Explanation

Laser Security Alarm Circuit

In this laser security alarm circuit we have used LM358 Dual Comparator IC for comparing voltages coming from LDR. Comparator is configured as Non-inverting mode and one 10K potentiometer is connected at its non-inverting terminal. An LDR is used for detecting light or laser light with respect to ground through a 10K resistor. And the midpoint of LDR and resistor is directly connected to inverting terminal of comparator.  A red LED is connected at output pin of comparator for indicating intruder detection. A mono-stable multi-vibrator is also used for activating buzzer and LED for a time period.  And a 9 volt battery is used for powering the circuit.

Working  of Laser Security Alarm Circuit

In this circuit we have set reference voltages of comparators by using potentiometer, we can say this sensitivity of the circuit. Comparator is configured in non-inverting mode. In this system we have placed laser light and LDR facing each other, so laser light continuously falls on LDR. Due to this a potential difference generated across the non-inverting pin of comparator, then comparator compare this potential difference with reference voltage and generate a digital output as HIGH. Before this we have configured 555 timer in mono-stable mode so we it required a LOW trigger pulse at its trigger pin to activate buzzer and LED. So we applied output of comparator at trigger pin of 555 timer. Even comparator’s output is HIGH when laser lights falls on LDR so at this time buzzer and LED are deactivated. When someone crosses the laser light due to this LDR lost the laser light and generates a different potential difference across the same comparator terminal. Then comparator generates an output as LOW. Due to this LOW signal 555 timer gets a LOW trigger pulse and activates buzzer and LED for a time periods that is defined by R1 and C1 at 555 timer circuit.

Laser Security Alarm Circuit

Main component of this circuit is LDR which detects dark and light. LDR is a light dependent resistor which changes his resistance according to the light. When light falls on the LDR surface, it reduces its resistance and when no light resistance of LDR become Maximum. Understand more about working of LDR in this Dark Detector Circuit.

The 555 timer time calculation formula in mono-stable mode is:

Time period T is given by :

T = 1.1 R1 * C1

Where T is time in seconds, R1 is resistance in ohm and C1 is capacitor in farads

To demonstrate this project we have used a small toy laser light.


Air Circuit Breaker

Air Circuit Breaker

Normally we are not used to seeing accidental explosions or fire blazing in our home or office when the current jumps above the safe level or when there are any other faults in the electrical system. When these accidental incidents are about to happen the circuit breaker cuts the power to the electrical system. Without circuit breakers (or the alternative, fuses), household electricity would be impractical because of the potential for fires and other mayhem resulting from simple wiring problems and equipment failures. It is one of the most important safety mechanisms either in the primary source of electricity or in the electrical distribution systems from where electricity is distributed in our home or in our home.

Air circuit breaker: When the breaker opens the current flow is interrupted that causes an electrical arc to be generated. This arc is cooled and extinguished in a controlled way, so that the gap between the contacts can again withstand the voltage in the circuit. When the fault condition is fixed, the contact is again closed to restore power to the interrupted circuit. When a circuit breaker uses compressed air to extinguish the arc the circuit breaker is called air circuit breaker (ACB).

Construction: Each phase of a three-phase Air Circuit Breaker (ACB) consists of 3 types of contacts, namely; main contacts which carry the load current, arcing contacts and the arcing horn.

The main contacts: Under normal operation the main contacts carry the load current. Therefore, main contact resistance must be low enough to prevent overheating, when current is flowing through it. The main contacts are therefore made up of a good conducting material such as copper, silver or copper with silver plating. Since these metals have relatively lower melting points, they can be damaged if arcing occurs. To prevent this damage, the main contacts do not make or break the current.

Arcing Contacts: Since no arcing must occur at the main contacts, arcing contacts are provided, which make or break the circuit current.

Arcing Horns: After the arc is established on the arcing contacts, it is transferred to the arcing horns during the opening of the arcing contacts. Their shape is designed to weaken or extinguish the arc.

Arc chute: The arc chute is a cooling chamber located at the top end of the breaker. It cools the hot gases which are produced when arcing occurs.

Operating mechanism: To understand the sequence of operation of various contacts in the air circuit breaker, one must realize that arcing must never occur at the main contacts.

Opening cycle: When the breaker is closed, the load current is conducted by the low resistance main contacts. But when the breaker opens, the main contacts open first and transfer the current to the arcing contacts. The arcing contacts open and an arc is established across the arcing horns. The arc rises to the top of the arcing horns and enters the arc chute where it is rapidly cooled by heat transferring mechanism in the cooling plates. Cooled gas deionizes that makes it unable to conduct electricity, and consequently arc is extinguished.

Closing cycle: In the closing cycle, the arcing contacts touch first to make the circuit again. Then the main contacts close and enable the circuit to flow electrical current.

Advantages of Air Circuit Breaker (ACB) over the other circuit breakers

* Relatively inexpensive
* Simple installation
* Simple construction
* Simple maintenance requirements

Air Circuit Breakers (ACB) are used in both low and high voltage current. They are commonly used in electrical distribution systems and NGD for voltage up to 15 KV. Air circuit breakers (ACB) which include operating mechanisms are mainly exposed to the environment. They protect for overload, short circuit and earth fault/ground fault. Most of air circuit breakers are used in indoor type substations.

Need Of Flexible Circuits

Flexible Circuits

In the world of electronics, necessity is the mother of all inventions, holds best applicable to the invention, evolution and development of flexible circuits in all types of electrical and electronics gadgets. The flexible circuits have just recently come of age as an interconnection technology, although it was originally developed around two decades ago.

In short, a flexible circuit is “a patterned arrangement of printed wiring utilizing flexible base material with or without flexible cover layers.”

Let us first understand the necessity of such circuits and the constraints posed by the earlier technology of printed circuit boards, which led to its invention.

Increased application of electronic devices such as car stereos, heart pacemakers, disk drives, digital cameras etc., requires greater flexibility of circuit designing and installation, to maximize space constraints. Since size of all gadgets is reducing exponentially, the need arose for designing circuits, which are functionally more capable and compact in size. Therefore came up flexible circuits to replace bulky wire attachments.

Miniaturization is the buzzword in the world of circuit designing. Great emphasis is there in reducing the size of the circuits without compromising on the performance. This required the engineer to improve the functionality and reliability of the circuits along with its flexibility. Flexible circuits are thus the solution to several spatial and orientation constraints earlier faced by fixed printed circuit boards.

How flexible circuits score over the rest?

Make –

1. A flexible circuit is made up of a flexible polymer film, which is laminated onto a thin sheet of copper that is engraved to produce a circuit pattern. The advantage of the polymer film is that the circuits can be designed and etched on both sides of the film. Another polymer overcoat is added to insulate the circuit and provide environmental protection.

2. The polymer film used for designing flexible circuits is KAPTON, which has several favourable characteristics and make it the best bet. These include heat resistance, dimensional stability, flexural capability. KAPTON’s excellent thermal stability provides a better base for surface mounting than hard boards.

3. The flat nature of such circuits offer considerable weight and space savings as compared to traditional wire harnesses. Thickness as low as 0.10mm and weight reductions of over 75% can be achieved.

Uses –

1. Flexible circuits can be used in designing several single or double-sided circuits with complex interconnections, shielding, and surface mounted devices in a multi-layer design. These multi-layer designs can also be combined with rigid circuit boards to create a rigid/flex circuit capable of supporting devices as needed.

2. Flexible circuits also give designers a third dimension to work with. As the name itself indicates, these circuits provide flexibility with which one can bend and shape around circuits along two or more planes during installation. This property can be used in complex and tight-fitting assemblies where it would be impossible to accommodate several rigid boards and harnesses.

3. Flexible circuits provide excellent means of reducing assembly time of a product due its properties of flawless integrate form and flexibility, thereby reducing number of assemble operations and testing time.

Thus, now the time for extinction of the printed circuit boards is fast approaching whereas development of flexible circuits is about to reach its pinnacle.


Flexible circuit is a pattern of conductors created on a bendable film, often polymers, which acts as an insulating base material. The top is coated with an insulating cover layer. A flexible circuit is in fact a counterpart to a rigid printed circuit board.

There are four basic types of flexible circuits, varying in degrees of complexity which can be used in different combinations to solve almost every interconnection design problem.

1. Single-sided flexible circuits –

This is the simplest of all types and provides maximum flexibility for dynamic applications. These simple circuits are also the most easily adaptable to SMT (surface mount technology), TAB (Tape Automated Bonding), and other developments in circuit technology. It is called single sided because the circuit allows access from one side only. Its applications are in the field of optical pick-up for computers, camera, camcorder, VCD players, vibration motors for mobile phones etc.

They are the most least expensive, and produced in the greatest volume. Single-sided circuits find maximum application in appliances where dynamism is required like in case of printers and disk drive heads.

Single layer circuit is created using a technique known as back baring or double access. This technique allows access to the metal conductors from both sides of the circuit. This method eliminates requirement of plate-through holes as required in multilayer circuits.

2. Double-sided flexible circuits –

As the name suggests, these circuits have two conductive layers that are usually accessible from both sides. Their main features include component assembly on both sides. Although, their capacity to flex reduces because of their thickness and complexity in design but their ability to interconnect between sides using plate-through hole helps to implement complex designs without compromising on flexibility.

These types of circuits are used when circuit density and layout cannot be routed on a single layer. Also used in shielding applications and dense surface mount assembly.

3. Multi-layer flexible circuits –

These circuits are ideal for complex, highly dense design requirements. Large numbers of conductors can be interwoven into a small package. Flexibility may be reduced somewhat, depending on the number of layers in the design. Multilayer circuits are the ideal technology to overcome design challenges like unavoidable crossovers, specific resistance requirements, elimination of crosstalk in sensitive circuits, additional shielding of ground planes, and high component density.

4. Rigid-flex circuits –

These are combination of rigid circuits and flex circuits. So it has the advantages of both. Rigid-flex circuits are a hybrid construction, consisting of rigid and flexible substrates laminated together into a single package and electrically interconnected by means of plate-through holes.
Rigid-flex boards are normally multilayer designs, but double-sided (two-metal layer) constructions are possible as well, and, in fact, have been selected for certain microelectronic chip-packaging applications, such as in the construction of hearing aids.

Such circuit types have been encouraged by military product designers, but, in recent years, this type of construction has gained popularity in the commercial world, as well.

All the above-discussed types of flexible circuit technology offer numerous viable solutions for those challenged with packaging electronic products. The technology has come of age and become a strong contender in the arena of electronic packaging technologies.

Only sky is the limit in the advancement of electronics packaging with flexible circuits.

What Causes Your Circuit Breaker to Burst

Circuit Breaker

Circuit Breakers are electrical components designed to protect us against the risks of electric shock and our homes against fire and other types of damage that can be caused by electrical faults. Each circuit breaker in your electrical switchboard usually protects one or more related circuits against overload, short circuit and earth leakage.

In order to understand what causes a circuit breaker to burst (or more commonly known as trip), we first need to understand what a circuit is and what the terms overload, short circuit and earth leakage mean.

What Are Circuits?

The electrical installations in our homes are divided into electrically separated segments known as circuits. Each circuit provides electricity to equipment in a very well defined and specific group. All the light fittings and light switches are found on one circuit known as the lighting circuit. Air-conditioners, heating and ventilation equipment are grouped on another circuit known as the HVAC circuit. And last but not least, socket outlets are grouped on a circuit known as the power circuit.

Each circuit is made up of cables, switches, connections and other electrical equipment designed to carry only the maximum electrical current specified by the manufacturer. When exposed to current exceeding this maximum, the electrical component may break down, melt or catch on fire. Circuit breakers were introduced to ensure this does not happen by disconnecting the electricity supply when the electrical current that flows exceeds the maximum capacity that the circuit components can handle.

Overloaded Circuits – The Main Reason a Circuit Breaker Trips

Have a look around your house at all the socket outlets. How many appliances are plugged into each socket outlet? Chances are you’ve got more than the circuit is designed for. Our increasing use of electrical and electronic devices puts more pressure on our electrical installations every day – sometimes to the point where the amount of electricity we use exceeds the amount that the circuit can safely give us without overheating or getting damaged. When this occurs, the circuit breaker in your switchboard will disconnect the circuit from the electrical supply.

Short Circuits – When Things Go Really Wrong

Whether you’re digging in the garden for the great new flower box, or drilling a hole in the wall to put up that lovely family picture, each time you make changes to the house you run the risk of damaging electrical cables concealed behind walls or in the soil. When you drill a hole through a cable or cut it with a spade, direct contact occurs between the individual wires in the cable. This is known as a short circuit. Electrical cables aren’t designed to withstand the current flowing in such a short circuit situation. In cases such as this, the short-circuit protection mechanism in the circuit breaker disconnects the electricity supply to ensure that the cable does not melt or catch fire.

Earth Leakage Currents

Sometimes known as ground fault current or residual current, this is electricity that flows from the electrical installation to the ground or other conductive materials of the house. Electrical systems are designed to pass current between the live conductors of the installation. When appliances like kettles, refrigerators and washing machines become faulty, they can allow current to flow through their metal parts into your body and down to the ground. This is a dangerous situation known as an earth leakage. Certain types of circuit breakers known as Residual Current Devices or Ground Fault Current Interrupters trip when they detect this current flowing to the ground to protect you from electric shock.

In summary, there are only 3 very simple reasons why circuit breakers trip:

1.) A circuit is overloaded, i.e. there are more devices connected to it than the circuit can actually accommodate.

2.) A short-circuit is present. Although less likely than an overload, a cable or other part of the fixed wiring may be damaged. You’ll need a qualified electrician to repair this fault and make your home safe again.

3.) An appliance is causing an earth leakage current to flow. Of all the scenarios, this is by far the most likely cause. Appliances become faulty all the time, and the result is a circuit breaker that keeps tripping.

What should you do if your circuit breaker keeps tripping?

Contact your local electrician to help you find out what the cause is. If you’re from Perth, Western Australia, contact a Perth electrician or one of the Perth electrical contractors.

Jaun Terblanche is the owner of Franklin Bell Electrical and Data Contractors in Perth, Western Australia. He draws on more than a decade of experience in the electrical and telecommunications industry to provide customers with fantastic customer service and guaranteed workmanship. If you need assistance with a tripping circuit breaker, visit their website at to request a free quote online.

A Review of Prominent Circuit Breaker Manufacturers

Circuit Breaker Manufacturers

The following article provides a review of prominent circuit breaker manufacturers.

ABB is at the forefront of circuit breaker manufacturers, offering homes and industries the ability to achieve maximum performance while limiting the negative impact on the environment. With companies operating in over 100 countries around the globe, ABB is a leader in its field. ABB offers products from miniature circuit breakers to molded-case breakers and guarantees its products are among the safest and most dependable on the market.

Perhaps better known for home appliances and products for various industries, Siemens is also a leading circuit breaker manufacturer. In 1998, Siemens executed a major recall of one of their circuit breaker products. The breaker in question was mostly used in hot tubs and spas. Although Siemens claims they are unaware of any injuries due to malfunction, they erred on the side of caution. The breakers were found to have the potential cause electrocution of people in hot tubs.

GE circuit breakers are probably some of the best-known and used circuit breakers on the market. GE offers circuit breakers that are compliant with Federal regulations. This circuit breaker manufacturer offers a wide range of products for all voltage needs. From home to industrial electrical necessities, GE has products for both low and high voltage electrical outputs.

ITE is credited as the founder of 5 kV air magnetic circuit breakers. They were among the first circuit breaker manufacturers to offer low energy and high quality solutions to industrial electrical needs. ITE also offers medium and high voltage circuit breakers for a variety of purposes.

Cutler-Hammer (Eaton) is also a well-known circuit breaker manufacturer. Perhaps one of the most innovative technologies to come from this company in recent years is the fireguard circuit breaker. Cutler-Hammer’s FireGuard provides protection from fire hazards that result from arcing faults. FireGuard circuit breakers will likely become the standard circuit breakers used in 21st century homes because they provide advanced protection against some of the most common causes of house fires.

The reliability of Federal Pacific, an established circuit breaker manufacturer, is questionable at best. These breakers have a notorious reputation for failure to trip when hit with a power surge. Some experts claim the rate to be upwards of 25%. Failure to trip during a power surge can cause structural fires. Rumors have circulated that the company was “de-listed” from the UL, although the company states they simply “went out of business”. Regardless of the actual reason for this, most electrical experts recommend discontinuing the use of these circuit breakers since most tests show an unacceptable failure rate.

Another circuit breaker manufacturer, Square D, has a long history in the circuit breaker business. This company was the first to offer plug-in type circuit breakers in 1951, which was then highly innovative technology. Since that time, Square D continues to be a leader in circuit breaker technology and offers a wide variety of products for both home and industry.

According to product reviews, ETA is the leading manufacturer of circuit breakers around the world. Their circuit breakers are crafted with precision and are used for a variety of circuit protection technologies. Thermal, magnetic, high-performance and electronic are just a few of ETA’s specialties. They continue to strive to create and produce the best circuit protection on the market.

Since 1947, Westinghouse circuit breakers have been among the most durable and reliable on the market. In tests, these breakers continue to deliver high performance to industries and their electrical needs. It is likely that Westinghouse will continue to be a leader in this field because they continually strive to meet the needs of advancing technologies.

What to Do If Your Circuit Breaker Trips

Circuit Breaker Trips

Circuit breakers are switches designed to protect your electrical circuits from damage caused by electrical overloads or short circuiting. Basically, electrical current flows into your home into the breaker box (usually located in the garage or in the basement) where it’s divided into a number of circuits and sent around the house. For rooms that only need electricity for small things like lights and TVs, you usually only need 15-amp circuits. For rooms with larger appliances, like the kitchen or bathroom, you’ll usually have 20-amp circuits. Some appliances, like the oven or dryer, are so large they need 30 – 50-amp circuits to themselves! When you hear about a circuit breaker “tripping,” it means the circuit has detected what’s known as a fault condition and has shut off that circuit to prevent the wiring from overheating and potentially igniting.

Resetting a tripped circuit breaker is usually pretty easy – just go back to the electrical panel, find the circuit that’s not facing the same direction as the rest and flip it back to where it belongs. If the breaker trips again right after you do this, that’s a problem – you need to figure out the cause of the issue before you can fix it.

If your circuit breaker trips upon resetting, you could be facing one of three problems:

  • Overloaded circuit
  • Short circuit
  • Ground fault

Overloaded Circuit

An overloaded circuit is the main thing that would cause your breakers to trip. Basically, it means there is more current flowing through the circuit than it is designed to handle, so it shuts off to prevent damage.

Remember earlier when we were talking about the different levels of current different rooms in your home get? When looking for an overloaded circuit, try to find any appliances on the same circuit that would be using more electricity than the circuit allowed. Pay particular attention to things like space heaters, toasters, hair dryers or straighteners, etc. – these tend to require the most current.

The solution for overloaded currents is usually pretty easy – just unplug things you’re not using! If this doesn’t solve the problem, call an electrician – you may have loose connections somewhere, though this is rare.

Short Circuit

If the problem is not caused by an overloaded circuit, a short circuit may be the issue. Short circuits are a little more serious than overloaded circuits, caused when the hot (black) wire touches another hot wire or a neutral wire. The best way to tell if you have a short circuit is to first inspect your power cords for damage or a melted appearance (make sure the appliance is unplugged) and to check the outlets or plugs for discoloration or a burned smell. If you can’t find the problem, call an electrician to take a look at it.

Ground Fault

If you’ve checked it out and you don’t think you have an overloaded or short circuit, check to see if a ground fault is causing your circuit breaker to trip. A ground fault condition exists when the hot (black) wire touches the ground (bare) wire or the side of a metal outlet box. If you have a ground fault.

Asynchronous Integrated Circuits Design

Asynchronous Integrated Circuits Design

Many modern integrated circuits are sequenced based on globally distributed periodic timing signals called clocks. This method of sequencing, synchronous, is prevalent and has contributed to the remarkable advancements in the semiconductor industry in form of chip density and speed in the last decades. For the trend to continue as proposed in Moore’s law, the number of transistors on a chip doubles about every two years, there are increasing requirements for enormous circuit complexity and transistor downscaling.

As the industry pursues these factors, many problems associated with switching delay, complexity management and clock distribution have placed limitation on the performance of synchronous system with an acceptable level of reliability. Consequently, the synchronous system design is challenged on foreseeable progress in device technology.

These concerns and other factors have caused resurgence in interest in the design of asynchronous or self-timed circuits that achieve sequencing without global clocks. Instead, synchronization among circuit elements is achieved through local handshakes based on generation and detection of request and acknowledgement signals.

Some notable advantages of asynchronous circuits over their synchronous counterparts are presented below:

* Average case performance. Synchronous circuits have to wait until all possible computations have completed before producing the results, thereby yielding the worst-case performance. In the asynchronous circuits, the system senses when computation has completed thereby enabling average case performance. For circuits like ripple carry adders with significantly worst-case delay than average-case delay, this can be an enormous saving in time.

* Design flexibility and cost reduction, with higher level logic design separated from lower timing design

* Separation of timing from functional correctness in certain types of asynchronous design styles thereby enabling insensitivity to delay variance in layout design, fabrication process, and operating environments.

* The asynchronous circuits consume less power than synchronous since signal transitions occur only in areas involved in current computation.

* The problem of clock skew evident in synchronous circuit is eliminated in the asynchronous circuit since there is no global clock to distribute. The clock skew, difference in arrival times of clock signal at different parts of the circuit, is one of the major problems in the synchronous design as feature size of transistors continues to decrease.

Asynchronous circuit design is not entirely new in theory and practice. It has been studied since the early 1940’s when the focus was mainly on mechanical relays and vacuum tube technologies. These studies resulted to two major theoretical models (Huffman and Muller models) in the 1950’s. Since then, the field of asynchronous circuits went through a number of high interest cycles with a huge amount of work accumulated. However, problems of switching hazards and ordering of operations encountered in early complex asynchronous circuits resulted to its replacement by synchronous circuits. Since then, the synchronous design has emerged as the prevalent design style with nearly all the third (and subsequent) generation computers based on synchronous system timing.

Despite the present unpopularity of the asynchronous circuits in the mainstream commercial chip production and some problems noted above, asynchronous design is an important research area. It promises at least with the combination of synchronous circuits to drive the next generation chip architecture that would achieve highly dependable, ultrahigh-performance computing in the 21st century.

The design of the asynchronous circuit follows the established hardware design flow, which involves in order: system specification, system design, circuit design, layout, verification, fabrication and testing though with major differences in concept. A notable one is the impractical nature of designing an asynchronous system based on ad-hoc fashion. With the use of clocks as in synchronous systems, lesser emphasis is placed on the dynamic state of the circuit whereas the asynchronous designer has to worry over hazard and ordering of operations. This makes it impossible to use the same design techniques applied in synchronous design to asynchronous design.

The design of asynchronous circuit begins with some assumption about gate and wire delay. It is very important that the chip designer examines and validates the assumption for the device technology, the fabrication process, and the operating environment that may impact on the system’s delay distribution throughout its lifetime. Based on this delay assumption, many theoretical models of asynchronous circuits have been identified.

There is the delay-insensitive model in which the correct operation of a circuit is independent of the delays in gates and in the wires connecting the gate, assuming that the delays are finite and positive. The speed-independent model developed by D.E. Muller assumes that gate delays are finite but unbounded, while there is no delay in wires. Another is the Huffman model, which assumes that the gate and wire delays are bounded and the upper bound is known.

For many practical circuit designs, these models are limited. For the examples in this discussion, quasi delay insensitive (QDI), which is a combination of the delay insensitive assumption and isochronic-fork assumption, is used. The latter is an assumption that the relative delay between two wires is less than the delay through a sequence of gates. It assumes that gates have arbitrary delay, and only makes relative timing assumptions on the propagation delay of some signals that fan-out to multiple gates.

Over the years, researchers have developed a method for the synthesis of asynchronous circuits whose correct functioning do not depend on the delays of gates and which permitted multiple concurrent switching signals. The VLSI computations are modeled using Communicating Hardware Processes (CHP) programs that describe their behavior algorithmically. The QDI circuits are synthesized from these programs using semantics-preserving transformations.

In conclusion, as the trend continues to build highly dependable, ultrahigh-performance computing in the 21st century, the asynchronous design promises to play a dominant role.

What Are Circuit Breakers?

Circuit Breakers

Circuit Breakers are devices that stop the electrical current of a circuit in the event of excess or very high voltage. Circuit breakers are handy, not only because they can protect against electrical fires but also because they can be reset. When a fuse blows out, it must be replaced each time, whereas circuit breakers are easily reset when tripped.

Each appliance in your home receives electrical currents by way of electrical circuit breakers. Circuit breakers are considered to be either main or individual. The main circuit breaker controls power to the entire house while individual circuit breakers transmit power to individual appliances.

Electrical circuit breakers are probably the most important safety feature in a building. A circuit breaker measures the amount of heat produced by the current or by the magnetic field created by the small coil inside the breaker. When the current becomes too high, the breaker will cut off the circuit to stop it. Fuses serve the same function but can only be used once. Anyone who has blown a fuse can tell you it is much easier to have circuit breakers.

Electrical circuit breakers are also useful for shutting down power to the entire house. If you need to do some electrical maintenance, either for the entire structure or individual electrical wires, shutting down the main breaker can be a safety tool. Although electrical waves are invisible, we all know they have great potential danger. You should label each individual electrical circuit breaker so it is easily accessible for future use.

Direct current, or DC circuit breakers, are commonly used in automobiles. DC circuit breakers, unlike alternate current (AC) breakers, only deliver currents in one direction. These types of circuit breakers are a renewable energy delivery source, and special precautions should be taken when using them.

Since all batteries have the capability of producing enormous amounts of energy when short-circuited, care should be taken to properly install the breaker, fuse and disconnects in a vehicle. Autos should have additional protection against over current for the battery and each of the branch circuits. Vehicle fires sometimes result when the owner does not take proper precautions.

DC circuit breakers often have plastic beads inside of the fuse. When the current becomes too heavy, these plastic beads can melt and fill the void inside the fuse and prevent an arc from forming. If the current is very heavy this can cause electrical fires. While DC circuit breakers are effective in preventing damage from an overload of current, they are only effective to a certain degree. Any power source using DC technology should have a backup master fuse to protect the vehicle against total short-circuit.

About Burglar Alarms and Circuits

Burglar Alarms

A general knowledge of circuitry is necessary to understand the working of a burglar alarm. Burglar alarm circuits are circuits that are put into an entryway. Energy courses through the path that lies between two opposite charged points in any electrical circuit. For example, when you turn the light on, you flip a switch that finishes the circuit.

Burglar alarm circuits are constructed in a similar manner, other than the fact that instead on flipping a switch, the alarm’s circuits are completed when it detects an intrusion like a breaking of a window, or opening a door, when it is activated.

Burglar alarm circuits can be of two kinds – open and closed circuit systems. In an open-circuit system, the circuit completes when the alarm is triggered. This is not logical. Think of the alarm system connected to the door. As long as the door is closed, there is no energy. It means that the closed door breaks the circuit, and if the door opens the circuit is completed and energy flows and sounds the alarm.

A closed-door system works the opposite way. Take the example of the same door, but the difference is that the closed door allows the energy to flow. If the intruder opens the door, the circuit breaks and triggers the alarm. When it comes to a closed-circuit, no energy means alarms sound immediately.

It is crucial that the correct burglar alarm circuit is placed at the entrance. Professionals realize the best possible circuit quickly. They mostly prefer the closed-circuit burglar alarm circuits, as the open-circuit is easy to deactivate. For instance, all that is necessary to deactivate the open-circuit is cutting the connected wires and picking the lock – the circuit never completes and the system fails.

When creating an alarm for your home, it is best to take the advice of a professional, especially if there are many valuables to protect. If you are trying to create your alarm system for fun, then you will be able to find many guides easily on the internet. All you will need is a battery to power the circuit, a switch to install on the door frame, a magnet in the door and a buzzer or alarm to connect to the circuit.

There are different types of burglar alarm circuits that range from simple to complex, but are very effective deterrents to burglars. To keep your home safe, there are various methods and it is very crucial to have different lines of defenses. Having a burglar alarm system is one good way to protect your family and home from uninvited people.