A Short Note About Circuit Diagrams & Symbols

                You probably already know that electrical engineers do not draw pictorial diagrams for every circuit.  Instead, they draw symbolic diagrams that represent a physical situation.  Do you remember this circuit?

Now, imagine that the element shown as a yellow rectangle is a battery.  We would draw this circuit as shown at the right.  Notice the symbol for the battery, with the "+" and "-" signs.  Notice also the two elements, shown here as rectangles.  Later, we will examine some symbols for particular elements.

        These diagrams may not look like the physical system, but they form a sort of language that allows precise communication between engineers about exactly what comprises a particular circuit.  Different kinds of electrical elements have different symbols.  Sometimes new symbols have to be invented when someone invents a new electrical device.

        Here are some symbols that are used for some common components.

Using Electronic Devices Makes Your Life Better!

By using these devices they allow you to do a task faster which gives you the time to do more tasks, so each device actually improves your life and allows you to accomplish more with your day to day activities, which in turn gives you more free time to enjoy electronic devices such as the ones that provide entertainment.

Current estimates on internet access is that approximately 25% of the world's population has access, the number seems low, but for North America alone the access rate is 73%, so through computers and the world wide web, access to knowledge has become very easy. Then there are other spin offs from manufacturing electronic devices like marketing and advertising a lot of which is put on or used in the electronic devices we've already bought, and they tell us how our lives can be even better with newer electronic devices, all these things come from these two urges.

Smart Tips to Take Your Electronic Devices Overseas

Executive Summary By Alexander O Mcgee

As the first step, the voltage of all your devices that you want to take overseas should be checked. If you find that your device says 110v - 220v, it means that the device comes in dual voltage so that you do not have to convert the voltage if you want to carry it with you.

If you find that the device is not dual voltage, the second step that you should do is to buy the small step-down converter or the transformer for helping you converting the voltage. Basically, most devices that you can buy in the USA come with thin, vertical metal prongs, while the standard overseas for the devices is round metal prongs.

How Electromagnetism Changed our World

Electromagnetism has created a revolution not only in the field of engineering, but also in various other fields like medicine, space, construction etc. Read here to know about various uses of electromagnetism in everyday life from household appliances to research labs.

Uses of Electromagnetism in Life

Whatever powered devices we use, from table clocks to microwave ovens, have some form of electromagnetic principle involved in their functioning. It is electromagnetism which has given the flexibility for switching of/on electricity as required.

Electromagnets are created by having an iron core wound with a conductor carrying current. The strength of the electromagnet depends upon the amount of current passing through the conductor. Also the current can be easily stopped and started to form an electromagnet and de-energize respectively as per the need of the work to be performed. This is the principle used for moving heavy objects in the scrap yard. Electricity is connected to the circuit to power the electromagnets when they are energized. Thus the magnets start to attract scrap metal (junk cars), and carry them to the designated area. After locating them in a particular location, the electricity is disconnected from the circuit, thus de-energizing the electromagnet, making the scrap metal detach from the magnet.

Uses in Home Appliances:

Many of our electrical home appliances use electromagnetism as a basic principle of working. If we take an example of an electric fan, the motor works on the principle of electromagnetic induction, which keeps it rotating on and on and thus making the blade hub of the fan to rotate, blowing air. Not restricting to fan, many other appliances use electromagnetism as a basic principle. Electric door bell works on this principle too. When the door bell button is put on, the coil gets energized, and due to the electromagnetic forces, the bell sounds. The working of an electric bell is discussed in detailed manner in one of our articles. The loudspeaker which we use for public announcements in meetings, or to transmit message over a long distance, is a perfect example for an electromagnetic appliance. The movement of the coil under the electromagnetic force produces sound which is heard over a very long distance.

Also the modern way of locking the door or a bank safe is to have a magnetic locking device. Either they may be having a number secret code or a magnetic card which when swiped opens the door. The number keys are stored in the magnetic tape on the back of the card, interacts with the magnetic card reader in the door. When the data stored on the card and the memory matches, the door opens. Similar principle is used in the bank’s safe lockers.

Uses in Computer Hardware and Memory Storage Devices:

Books are no more required to be carried to schools or colleges. Books, as heavy as hundreds of kilograms can be stored in few milligrams of memory stick. The data are stored in electromagnetic format in the form of bits and bytes. Even the computer hard ware is having a magnetic tape which works on the electromagnetic principle. Not limiting to this, the olden day VCR’s and VCP’s are having huge rolls of magnetic tapes, which had data in it. This can be recorded or read by electromagnetic means only. Also the computer and Televisions use high current electromagnets to produce a beam of electrons from the cathode ray tube. However now a days we use LCD’s and Plasma types.

Power Circuits and Communication Devices:

The telephones and mobiles we use to make a call over huge distances could have not taken shape with out electromagnetism. The interaction of the signals and the electromagnetic pulses, make the telephones and mobiles very handy. In power circuits, we use a device called relays, which has the potential to cut down a large current to the load, with the application of small amount of current. A small magnetic coil, which when energized, makes or brakes contact, thus doing a greater amount of work on the other end. Not to forget the usage of electromagnetism in medical field. Everyone must have heard of MRI scans. MRI- is the acronym for Magnetic Resonance Imaging. This sophisticated equipment can scan any minute details in the human body on the principle of electromagnetism.

Modern day fast trains under operation in Japan and Germany are hugely dependant on the electromagnetic principle.

Thus it is evident that the usage of electromagnetism is wide and everywhere. Everyday more and more equipments take birth in the market due to the development in the magnetism and electromagnetic studies.

Few decades ago, only few places on our Planet Earth had the facility to enjoy the electricity and electronic devices. But recent developments led to fast track life style and rapid competitive improvement in every field competing with every country. With the introduction of electricity and electrical devices, electronic devices, and communication equipments, it is possible to reach any part of the world within few hours. Books which weigh several hundred kilograms can be stored in few milligrams of memory stick. These rapid changes started to happen after the introduction and usage of electromagnetism. The above applications are only a few of many more uses of elctromagnetism. It plays a very vital role in our day-to-day life.

Electrical Engineering: Career Opportunities Abound

Young students pursuing Electrical Engineering can very easily get rattled seeing the huge advancements of the modern electronic world, and get dejected. But they should look at the other side of the coin which clearly shows that the benefits of being an electrical engineer are enormous.

Today the world around us is changing rapidly. New technologies emerge and become obsolete in no time, it seems. In such a fast pace of electronic advancement, individuals equipped with such a “primitive” kind of technology like electrical engineering can feel low, inferior, and depressed. For them the chances of securing a sound position of income and honor may look quite bleak and remote.

But this wrong impression among electrical engineers concerning their profession can be quite baseless and drastically wrong. If tried, even in the present hi-tech world one can easily find out that the benefits of being an electrical engineer are diversified, plenty, and very lucrative.

Role of an Electrical Engineer in Society and Industry

The word “electrical” was derived from electricity. And every one of us should bear in mind that electricity is the only fundamental driving force of today's so called “ultra modern hi-tech world.” If the present super advanced electronic world is the “body,” electricity is the “blood,” and surely the electrical engineers are playing an important part to become the “soul” of this body. For example, in electric power generation plants, may it be a hydro or a nuclear power plant, it’s the electrical engineers who are managing the show, and without them the entire nation may suddenly fall into total darkness, chaos, and a stand still. Or even in our day to day life when the water pump motor of our house or apartment is out of order, it’s an electrical engineer who comes to the rescue. It’s only due to the efforts of an electrical engineer that any problem in our domestic wiring is solved within minutes. Obviously nobody will think of calling a microcontroller engineer to fix the above mentioned problems.

Options are Wide Open

As so far discussed the benefits of being an electrical engineer are ample. We will try to analyze and learn them in the following point by point manner:

• Today there are many industries which are running solely due to the involvement of qualified and experienced electrical engineers.

• There are industries manufacturing heavy electrical items like motors, transformers, pumps, cables, and even steel who are always very much in need of qualified electrical engineers.

• The scope for these engineers is also wide open in the industries manufacturing locomotive and auto electrical equipment.

• There is another very innovative option that today more and more electrical engineers are engaging themselves into. It is a simple idea of becoming self-employed.

• Many electrical engineers today are opting to have their own electrical workshops and shops rather than going for tedious and monotonous routine factory jobs.

• Having a shop can act as a double source of income for these smart electrical engineers. Along with the selling of the electrical fittings and appliances, they can milk a fat income through some prompt after sales service.

• Many industries like to outsource their job works. Electrical engineers with their own workshops can take orders from these companies and earn handsome packages.

Well it seems now the tables have turned and is clear that compared to the other professions, maybe the benefits of being an electrical engineer are unlimited and are here to stay.

10 Simple Electrical Circuits Discussed

An electrical circuit diagram is a simplified schematic representation of an electric circuit. It uses standard symbols for the components in the circuit and does not show the physical arrangements of the components. In this article we discuss 10 simple electrical circuits.

Daily life on the earth is nearly impossible without electricity. From homes to big industries, we all depend on electricity. We know that electric current flows in a closed circuit. An electrical circuit is a closed loop in which continuous electrical current goes from the supply to the load. If you are trying to describe an electrical circuit to your friend or neighbor, it is likely that you have to draw the connection. For example, if you want to explain a lighting circuit, it can take more time to draw the bulb, battery, and wires because different people draw various components of the circuit in different ways and this may take a long time to explain. Therefore, a better way is to learn how to show simple electrical circuits. In this article we give the drawings for some simple electric circuits: AC lighting circuit, battery charging circuit, energy meter, switch circuit, air conditioning circuit, thermocouple circuit, DC lighting circuit, multimeter circuit, current transformer circuit, and single phase motor circuit.

AC Circuit for Lamp

For a lamp we need two wires; one is the neutral wire and the other is the live wire. These two wires are connected from the lamp to the main supply panel. It is advisable to use different colours for live wires and neutral wires. The universal practice is to use the colour red for live wires and a black colour for the neutral wire. For switching ON and OFF the lamp we need a control called a switch - provided in the live wire between the main supply and lamp. If the switch is ON, the electric circuit is closed and the lamp glows, and if the switch is OFF, it will disconnect the power supply to the lamp. For safe operation this wiring is placed in a box called a switch box. The switch wire and live wire are a single wire; it is just cut in between to connect the switch. In case you want to change the lamp, don’t forget to switch OFF the lamp and if possible disconnect the power supply to the circuit.

Battery Charging Circuit

Battery charging is done by means of a rectifier. The main function of the rectifier is to convert AC (alternating current) into DC (direct current). The rectifier shown in the diagram is the bridge rectifier, which has four diodes connected in the form of a bridge. Resistance is added in the circuit to limit the flow of current. When the supply is given to the rectifier through a step down transformer, it converts the AC supply into DC supply and this flows to the battery, thereby charging it. Usually this circuit is enclosed in a battery charger unit or inverter and only the terminals emerge out of the charger unit to be connected to the battery for charging.

Air Conditioning Electric Circuit

Air conditioning is a process that heats, cools, cleans, and circulates air together with the control of its moisture content. The electric aspect of AC comprises the power equipment for motors and starters for the compressor and condenser fans. Associated electric equipment includes solenoid valves, high and low pressure switch, and high and low temperature switch, together with the safety cut-outs for over current, under voltage etc.

The compressor and condenser fans are driven by a simple fixed speed 3 phase AC induction motor, each with its own starter and supplied from a distribution board. Routine electric maintenance and fault finding on the motor and starters involves cleaning, checking of connections, insulation tests, etc.

Switch Circuit

We operate switches for lights, fans etc. many times a day but we usually don't try to see the connection made inside the switch. The function of the switch is to connect or complete the circuit going to the load from the supply. It has moving contacts which are normally open.

As shown in the diagram, the power supply to the load is through the switching circuit, and therefore the power supply can be cut by keeping the switch open.

DC Lighting Circuit

For a small LED lamp, normally we use a DC supply (battery). This circuit is very simple. The battery has two points, anode and cathode. The anode is positive and cathode is negative. A lamp has two terminals - one is positive and the other is negative. The positive terminal of the lamp is connected to the anode and the negative terminal of the lamp is connected to the cathode of the battery. Once the connection is made the lamp will glow. To enable switching ON or OFF, connect a switch (diagram above) in between any one wire that will cut off or supply DC voltage to the LED bulb.

Electrical Circuit Theory and Network Theorems

Approaches to Circuit Analysis

There are few theorems that can be applied to find the solution of electrical networks by simplifying the network itself or it can be used to calculate their analytical solution easily. The electrical circuit theorems can also be applied to A.C systems, with only one difference: replacing the ohmic resistance of the D.C system with impedance.

There are two general approaches to network analysis:

1. The Direct Method:

In this method, the network is left in its original form while determining it different voltages and currents. Such method are usually restricted to fairly simple circuits and include Kirchhoff’s law, loop analysis, nodal analysis, superposition theorem, compensation theorem, and reciprocity theorem, etc.

2. The Network Reduction Method:

In this method, the original network is converted into a much simpler equivalent circuit for a rapid calculation of different quantities. This method can be applied to a simple as well as complicated network. Examples of this method are: Delta/Star and Star/Delta conversion, Thevenin’s theorem, and Norton’s theorem, etc.

Understanding Basic Electronic Theory

When it comes to developing your own electronic projects, a prior knowledge of basic circuit theory becomes quite imperative. Read on to learn the bare essentials required for designing your own basic electronic circuits.

What is Basic Electronic Circuit Theory?

In simple terms, electronics may be understood as a branch of science that utilizes and controls the flow of electrons through specially designed networks of active and passive devices to produce a desired result. These networks are basically an interconnection of selected electronic components and constitute an electronic circuit. The electronic components involved are fundamentally classified as active and passive components. Active components play a live role in dimensioning or optimizing the flow of electrons through them as per their design specifications. These are all particularly semiconductor parts which include devices like LEDs, diodes, transistors, ICs, SCRs, triacs and many more, the list may be too long. The passive components are normally made up of carbon or chemical electrolytes and although not able to contribute actively yet play an important part in association with the active devices and complement them in every respect. Without these components, it probably won’t be feasible to design an electronic circuit. Components like resistors, capacitors, inductors etc. come under the passive electronic components.

How to Understand the Basic Electronic Components and Their Applications?

Diode: As shown in the picture a diode is a two terminal component and is recognized by a band or a ring at one of its ends.

In the symbol the band is indicated by a straight line at the arrow point. The lead which is terminating from this side is the cathode and the other one is the anode.

A diode will always allow a positive voltage to pass through its anode towards the cathode and block the other way round. Due to this particular characteristic, diodes are also used as rectifiers to convert AC into DC.

LED: LEDs are quite similar to the normal diodes as explained above, but sinceLEDs are able to emit light in the process, are specifically used as indicators and in other forms of lighting purposes. LEDs are unable to tolerate high currents and therefore always incorporate a series resistor to dimension the required minimum current through them.

Transistor: We all are quite familiar to this versatile member of the electronic family. Transistors are basically used to amplify small electrical signals and also for switching purposes.

Resistor: Since most semiconductor devices are sensitive to high currents, resistors are employed to restrict a correct flow of current through them. The values of these resistors are dimensioned by calculating them using various formulas.

The following examples will clearly explain regarding how basic electronic circuits are designed:

As shown in the figure, the trigger voltage which is generally received from an IC output or some other similar source is applied to R1. The received current is correctly optimized through R1 and is used to bias the transistor T1 so that it may conduct and light up the LED connected to its collector arm.

As explained above, resistor R2 has been incorporated to safeguard the LED from excessive currents. The value of R2 is calculated using the following formula:

R2 = (U_S - U_LED) ÷ I_LED

Here U_S = Supply Voltage,

U_LED = Minimum forward voltage drop of the LED used,

And I_LED = Current utilized by the LED for optimum brightness (normally 10 mA is found to be quite sufficient).

The value of R1 may be achieved using the following formula:

R1= (U_b - 0.6) × Hfe / I_LOAD

Here U_b = source voltage to R1,

Hfe = Forward current gain of T1 used (you may take the minimum value: 150)

I_LOAD = Current required to operate the collector load (a LED here).

The LED in the circuit may be easily replaced by a relay, in case it becomes necessary to switch heavy loads at the output. The base resistor value then may also be calculated appropriately using the above formula.

Sometimes we may find the source voltage to R1 too small and difficult for T1 to sense. During such conditions an interesting modification can be introduced by conjugating another transistor with T1 as shown in the adjoining figure. This configuration is termed as a Darlington pair.

Here the received weak signals are amplified to a suitable level by the first transistor and applied to the base of the next transistor which amplifies it sufficiently to energize the collector load.

Capacitor: It is another indispensable passive electronic component and inevitably finds a place in almost all electronic circuits. They are basically used to block DC and allow AC but may also find important applications in producing time delays, suppressing or filtering noise..

If a capacitor is linked with the above circuit, interesting results are obtained. The two adjoining figures may be explained respectively as follows:

In the first fig. T1 continues to conduct for quite some time even after the trigger voltage is cut OFF due to the charge stored inside C1, indicating how a capacitor is used in producing time delays.

The second circuit indicates how a capacitor can be used to produce a momentary pulse so that on receiving a base voltage the transistor and its collector load is switched ON only for an instant and then switched OFF. Here the trigger signal is allowed to pass instantaneously only during the charging process of C1 and inhibits its flow once C1 gets fully charged.

Well, I can just go on and on without ending as the topic of electronic basic circuit theory can be infinitely long. But for the time being, I will have to conclude here. Any raised eyebrows? Please let me know through your comments (comments need moderation, may take time to appear).

What is Electromagnetism and its Applications?

Electromagnetism is a branch of physics which deals with electricity and magnetism and the interaction between them. It was first discovered in the 19th century and has extensive application in today's world of physics.

Electromagnetism is the branch of physics that deals with electricity and magnetism and the interaction between them. It was first discovered in the 19th century and has extensive application in today's world of physics.

Electromagnetism is basically the science of electromagnetic fields. An electromagnetic field is the field produced by objects that are charged electrically. Radio waves, infrared waves, Ultraviolet waves, and x-rays are all electromagnetic fields in a certain range of frequency. Electricity is produced by the changing of magnetic field. The phenomenon is also called "electromagnetic induction." Similarly the magnetic field is produced by motion of electric charges.

The basic law of electromagnetism is known as "Faraday's law of Induction." The phenomenon of electromagnetism was discovered in the 19th century, and this led to the discovery of the "special theory of relativity" by Albert Einstein. According to his theory, electric and magnetic fields could be converted into one another with a relative motion. This phenomenon and its applications were discovered because of the many contributions from great scientists and physicists such as Michael Faraday, James Clerk Maxwell, Oliver Heaviside, and Heinrich Hertz. In 1802, an Italian scholar demonstrated the relationship between electricity and magnetism by deflecting a magnetic needle with electrostatic charges.

Electromagnetism is basically a conjecture of a combined expression of an underlying force, known as "electromagnetic force." This force can be seen when an electric charge is moving. This movement produces magnetism. This idea was presented by James Clerk Maxwell who published the theory of electricity and magnetism in 1865. Based on this theory many applications and other effects were discovered by other scientists. Electromagnetism has been extended to the area of quantum physics as well where light propagates as a wave and interacts as a particle.

It has been proved that electricity can give rise to magnetism and vice versa. A very simple example is that of an "electric transformer." The exchanges take place inside the transformer that gives rise to electromagnetic waves. Another fact about these waves is that they do not need a medium to propagate although their speed is relatively slower when traveling through transparent substances.

Electromagnetic Waves

Electromagnetic waves were first discovered by James Clerk Maxwell and they were confirmed after wards by Heinrich Hertz. Afterward, a wave form of electric and magnetic equations was derived by Maxwell which showed that the electric and magnetic fields had wave-like nature. The factors which differentiate electromagnetic waves from each other are frequency, amplitude and polarization. For example, a laser beam is coherent and the radiation is of only one frequency. There are other types of waves varying with their frequencies such as radio waves which are at very low frequencies and gamma rays and x-rays of very high frequency. Electromagnetic waves can propagate to very long distances and they are not affected by any kind of obstacles whether they are huge walls or towers.

This special interaction of electricity and magnetism has led to great advancements in modern science and technology, and efforts are being made to discover more about electromagnetism and its applications. Other forces are gravitational forces, strong and weak forces. Electromagnetism has also been combined with the weak force which is known as "Electroweak force."

Applications of Electromagnetism

Electromagnetism has numerous applications in today's world of science and physics. The very basic application of electromagnetism is in the use of motors. The motor has a switch that continuously switches the polarity of the outside of motor. An electromagnet does the same thing. We can change the direction by simply reversing the current. The inside of the motor has an electromagnet, but the current is controlled in such a way that the outside magnet repels it.

Another very useful application of electromagnetism is the "CAT scan machine." This machine is usually used in hospitals to diagnose a disease. As we know that current is present in our body and the stronger the current, the strong is the magnetic field. This scanning technology is able to pick up the magnetic fields, and it can be easily identified where there is a great amount of electrical activity inside the body.

The work of the human brain is based on electromagnetism. Electrical impulses cause the operations inside the brain and it has some magnetic field. When two magnetic fields cross each other inside the brain, interference occurs which is not healthy for the brain.

How to Make an Electric Lamp Circuit for a Science Project

You can easily make your own electric lamp circuit for a science project. The project does not use household current, depending instead on a safe size D battery as the power source. It’s a simple circuit made of a battery, wires and a light bulb, with the addition of a knife blade switch so that you can turn the light on and off. Utilizing these basic items will allow you to better understand how an electric circuit works.

1) Strip 1-inch of the insulation off both ends of each piece of copper bell wire. To do this, put each piece of wire in the notch of the wire stripper, leaving 1-inch of wire hanging out one side of the stripper. Close the handles of the wire stripper and rotate it around the wire, cutting through the insulation in the process. Open the wire stripper and pull off the insulation.

2) Connect one end of a 9-inch wire to one of the screw terminals on the knife blade switch. To connect the wires to the screw terminals, wrap the bare end of the wire around the base of the screw in a loop. Tighten the screw to hold the wire in place. Attach the other end of the wire to the positive terminal of the battery holder.

3) Attach another 9-inch wire to the second screw terminal on the knife blade switch. Open the switch by putting the movable blade in the upright, vertical position. Connect the other end of this wire to a screw terminal on the lamp holder.

4) Screw the light bulb into the lamp holder. Attach one end of the 18-inch wire to the remaining terminal on the lamp holder.

5) Connect the free end of the 18-inch wire to the negative terminal on the battery holder. Place the battery in the battery holder.

6) Push the movable blade of the knife blade switch in the down position to turn on the light bulb. The circuit is now closed, allowing the electricity to flow from the battery through the switch to the light bulb and back to the battery.

7) Turn off the bulb by pushing the movable blade of the knife blade switch to the upright, vertical position. This breaks the circuit and stops the electricity from lighting the bulb.

Quantum Physics: Disentangling Strange Behavior Of Qubits

Current technology enables the building of electrical circuits similar to those we use at home but reduced thousands of times in size to a micrometric scale of thousandths of a millimeter. When these circuits are built of superconductor materials and at near-absolute zero cryogenic temperatures, the world of everyday physics is left behind and the amazing world of quantum physics is entered. In this circuit the behavior is something like an artificial atom (i.e. like the so-called quantum bits ("qubits") of quantum computers) and the concepts of quantum optics, quantum information and condensed matter are mixed.