Scanners: Explained.

 Introduction:

          If you need a copy of a document that is sitting on your table. For this, with your PC, you use your flatbed scanner to convert it into a soft copy.

 

Mechanism:

          A typical scanner uses something called a charge-coupled device or CCD to determine what's on the page. The main idea here is that the CCD can convert light into an electrical charge which it then sends to your computer as digital data. So, when you start scanning a document, that bright light you see coming from inside is typically from either a xenon lamp or a cold cathode which as you may know is similar to what people use in PC case lighting a few years back. It's the sheet of paper and reflected back to a series of mirrors underneath the glass surface, and then focused by a lens onto an array of CCD sensors since darker areas of the page containing things like text and clipart will reflect less light in the blank. Usually, in white areas, the CCD array will see these differences which will show up as an accurate image of your document on your computer screen. If you've ever had a scan of something bulky and had to leave the lid open a little bit you'll have noticed the scan is black in areas that aren't covered by anything. This is because nothing's there to reflect the light. Though, modern software is often smart enough to crop these areas out for you. CCD rates are also what determine the scanner's true resolution. The more sensors in the array the more points of light it can capture and the more pixels it can send to your computer. If you're in the market for a scanner, make sure to check that the resolution on the spec sheet is the hardware resolution that reflects the true abilities of the CCD array, not some fake number achieved through software trickery like interpolation that uses average values of nearby pixels to approximate a higher pixel count image.

But what about color scanning? This uses additional lenses and built-in color filters to separate the scan into red blue and green versions which are then processed to determine what the actual colors of your original document are. Although, this is usually done with just one pass of the scanner. Some older models lack these additional lenses and so, they need multiple passes to complete a color scan which is why they were much slower in color mode. But not every consumer-level scanner works this way. Some flatbeds use something called a contact image sensor or CIS instead of these C CDs. These are simpler and construction uses an array of LEDs to shine a light on the document. So, an image sensor can essentially take a snapshot of it.  Although the scans from the CIS are typically lower quality than CCD scanners, CIS is a cheaper, more lightweight, and more efficient technology. So, you'll find it in a lot of small portable scanners that can be powered solely from a USB port instead of requiring a wall outlet.

Of course, there are other types of scanners out there such as expensive drum scanners with high dynamic range for professional applications as well as 3d scanners but the discussed above were the main focus here.

 

Stay tuned and Bye.

 

Types of Printers along with types: Explained.

 

Types of Printers:        

          There are two widely used types of printers for home and office use that are:

·        Inkjet Printers

·        Laser Printers

 

Working of Laser Printers:

          Let's have a look at them in a little depth. First up, we've got laser printers that use laser beams to create prints. Laser printers also contain a rotating cylinder coated with a photosensitive electrically charged material and a series of mirrors. When you send a document to a laser printer, the laser light is reflected by the mirrors onto the cylinder which neutralizes the electrical charge in specific areas. Thanks to the rotation of both the cylinder and the mirrors as well. As the laser turning on and off at precisely the correct moments the areas hit by the laser correspond to the actual print and when toner particles hit the cylinder, they only stick to the areas exposed to the laser light because the toner itself has an electrical charge to cool. Right then, a sheet of paper is pressed against the cylinder and the toner is transferred through to the paper using heat which fuses the toner to it. That is why pages fresh out of a laser printer are always so nice and cuddly warm due to the precision of the laser.

          These kinds of printers are great for producing crisp clear.

 

Working of Inkjet Printers:

          The inkjet printer is very different like the name says. This sort of printer uses liquid ink instead of solid toner particles. In consumer models, ink inside of those expensive cartridges is heated with an electrical charge causing a small amount to vaporize and form a bubble on the nozzle. The bubble then collapses and the pressure difference pulls a droplet of ink out of the cartridge and onto the paper because their internal workings are simpler than laser printers. They tend to be significantly cheaper and although they can't print as quickly. They give much better print quality for photos making them the go-to choice if you like to print your own snapshots at home.

Unfortunately, though many inkjet owners have been disappointed by their printer’s reliability. So then, why is it that they seem to give people such a hard time? Well, part of it is because printers have so many small moving parts that can break or wear out. Not to mention, the small nozzles that can clog easily but perhaps a bigger part of the reason is that the business model of inkjet manufacturers the printers themselves are frequently sold at a loss.

So, ink refills can cost more than the actual printers themselves. Also, many cartridges contain smart chips that report that they're empty even if there is still leftover ink. But fortunately, there are workarounds for this that you can find online. There are many alternatives as well, such as Epson’s new system that uses permanent high-capacity ink tanks instead of pricey cartridges.

 

That’s all for today.

Stay tuned, and Bye.

 

Vacuum Cleaners: Explained.

 

Vacuum Cleaners:

            Materials flow from one location to another when the pressure difference is created between two locations. A vacuum cleaner is based on that principle.

The suction will be created in front of the centrifugal fan and negative pressure will create behind the centrifugal fan.

Working:

            Now let’s have a look at the working of a vacuum cleaner with parts. Firstly, we have a vacuum cleaner chamber. On the front of the vacuum cleaner chamber, there is a filter for filtering the dust particles and giving clean air to the front area. There is a motor and a centrifugal fan with a pipe attached to the cleaning apparatus. Now, we see the working of a vacuum cleaner. When we apply voltage to the cleaner, the fan will start rotating, creating a pressure difference. Then, this pressure difference will suck the air from this pipe and this pipe will suck the air with the dust particles and this air with dust particles will reach the filter. There, it will be filtered and clean air will be aborted from the filter. This clean air will reach the atmosphere, so this difference of pressure will suck the air from the outside to inside in the vacuum cleaner suction pressure will be created in the front of the centrifugal fan and negative pressure we create in the behind of the centrifugal fan.

 

This was the working of a simple vacuum cleaner.

Stay tuned.

Bye.

Microwave ovens: Explained.

 

Microwave ovens could be one of the greatest inventions of the 20th century. But how exactly do they work?

Let's explore the science behind it.

Microwaves:

            Microwaves are electromagnetic waves that fall in between radio waves and infrared waves on the electromagnetic spectrum.

Microwave Ovens:

            Microwave ovens use microwaves to heat the food while radio waves can be tens of kilometers long. Microwaves used in cooking are just about 12 centimeters from crest to crest.

With the frequency of 2.45 gigahertz, waves at these frequencies are absorbed by food molecules especially, the molecules of water. These water molecules have a positive and negative end same as a bar magnet with a North and South Pole. As the microwave changes its polarity, the polar molecules rotate at the same frequency millions of times a second. To line up with the changing field, all this agitation on the molecular level creates friction which heats up the food. But since, microwaves don't interact with plastics, glass, or ceramics, only the food is heated

So how does a microwave oven turn electricity into heat?

            Inside the strong metal box, microwaves are created using a device called a magnetron.

A transformer steps up the standard household electricity from the wall socket to around 4000 volts. This increased voltage heats up the cathode or the filament which is at the center of the device. A ring-shaped anode surrounds the filament and electrons are emitted as the filament heats up and rushed towards the anode or the positive terminal. The anode has slots cut into it called resonant cavities.

            Two ring magnets are placed above and below the anode, which generates a magnetic field that is parallel to the cathode. Normally when the filament is heated, the electrons which are negatively charged particles would rush out in a straight line towards an anode, which has a positive potential. However, due to the magnetic field, the electrons bend back towards the filament and follow a curved path. These electrons spiral as they leave the filament-forming an interesting pinwheel pattern.

As the charges on the cavities oscillate, the tip of the pinwheel spins which in turn creates microwaves in the resonant cavities.

            The microwaves are then transmitted into the compartment through a channel called a waveguide. These waves bounce back and forth off the reflexive mirror eventually penetrating the food in turn heating it up.

 

This was the working principle of a microwave oven.

Stay tuned.

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Refrigerators: Explained.

 

Introduction:

            Before refrigeration, keeping food fresh was a pretty tough job. In those days, people used to salt their food or bury it in the snow to keep it fresh. But now, the refrigerator has changed the way we conduct our daily lives, making it easier to preserve food.

Working:

            Have you ever wondered that how a refrigerator keeps your food fresh and provides you with a refreshingly chilled beverage on a hot day? Well, let's find out.

            Refrigeration is actually quite simple to understand the principles behind it. Just remember that when the liquid evaporates, it absorbs heat and when it condenses, it releases heat.

A simple example is that when your hand is wet, it feels cold. This is the process of the water evaporating and cooling your hand on a very humid hot day.

Components:

            A refrigerator uses five major components:

·         An expansion device

·         Evaporator coils

·         A compressor

·         Condenser coils

·         A refrigerant

            The refrigerant is a liquid that enters in the expansion device. As it passes through, the sudden drop in pressure makes it expand cool, and turn into a gas. As the refrigerant flows around the evaporator coil, it absorbs and removes heat from the food inside. The compressor squeezes the refrigerant, raising its temperature and pressure. It's now a hot high-pressure gas. The refrigerant then flows through condenser coils on the back of the fridge, radiating its heat to the atmosphere and cooling back into a liquid. As it does so, the refrigerant then re-enters the expansion device and the cycle repeats itself. So basically, heat is constantly picked up from the inside of the refrigerator and taken outside of it.

 

 

Stay tuned.

Bye.

Air Conditioners: Explained.

 

Major Parts:

            In the major components or parts of an air-conditioner, there is a compressor, there is a condenser, an expansion valve, and finally, an evaporator that can also be called a cooling effect generator. There is a fan over here, and these are the connecting pipes that connect all these parts together.

Working:

            Let's look into the working of all parts of the air-conditioner. The basic principle of air-conditioning is to remove the heat from one area and replace it with Chilled air and expel the hot air to the outside atmosphere and for this exchange of heat, we use a special fluid which is called refrigerant or coolant. We can think of the refrigerant as the messenger or traveler because this refrigerant is the actual carrier or medium of heat exchange between the external environment and these internal components by brand name. We call this refrigerant Freon thus, the coolant or refrigerant Freon is a fluid that flows through these connecting pipes and parts of the air-conditioner and changes States from liquid to vapor or vapor to liquid at convenient temperatures.

For the refrigeration cycle or air-conditioning

Process, now at the first step the compressor starts working. The job of the compressor is to pressurize or compress the refrigerant Freon and we know that if pressure increases, it also increases. The temperature so when the compressor compresses the refrigerant Freon in its gaseous state by squeezing the gas very tightly together. It will heat up we heat up the refrigerant to get its temperature higher than the outdoor temperature. Since the heat naturally flows from hotter to colder bodies. To dispense heat outdoors, the refrigerant must be hotter than the air outdoors. This is why, we need the compressor to increase its pressure and thus, its temperature then, this high pressure and high-temperature gas vapor of Freon will go to the condenser through these connecting pipes. After that in the condenser, high pressure and high-temperature gas vapor of Freon will change its form from gas to liquid at the same temperature that is. The temperature will remain the same the condenser will just change the physical state of the refrigerant Freon from gaseous form to liquid. This condenser coil is in the outdoor air conditioning unit, placed outside of our home. The heat energy is absorbed from the hot gaseous refrigerant. With the aid of the condenser fan, this heat is expelled to the environment as the heat leaves the refrigerant to the outside environment, turning back into a liquid.

We can think of it as the opposite of the evaporator coil because the evaporator coils contain cold refrigerant whereas the condenser coils contain hot refrigerant. Now, this high temperature condensed liquid refrigerant will leave the condenser, and enter the expansion valves through this connecting pipe. When the refrigerant leaves the condenser in its liquid state, it has already given away heat to become liquid from the gas. But it is still too hot to enter the evaporator coils. Before the refrigerant passes to the evaporator coils, it must be cooled down. This is where the expansion valve comes in.

We know that compression and expansion are opposites from one another. Here in compression, we need to increase the temperature of the refrigerant. So, we increased pressure by compressing the refrigerant Freon and thus, increased the temperature. So similarly, now we need to cool down the temperature of the liquid refrigerant that is coming from the condenser. So for this purpose, we have to cause expansion, reducing the pressure between the refrigerant molecules, which will cool it down simultaneously.

 

Now, this is what happens in the expansion valve. The expansion valve depressurizes i.e. lowers the pressure of the refrigerant and cools it down. It also controls the amount of refrigerant or voltage flow entering the evaporator. Now, the low-pressure cold liquid refrigerant enters the space where we want to produce cooling. That is this cold liquid is now ready to absorb heat from the indoor environment and produce cooling. So, this low-pressure cold liquid refrigerant enters the evaporator coils. These evaporator coils are very important to an air-conditioner. The evaporator is the indoor air conditioning unit. We pulse inside our home where the air conditioner actually picks up the heat from inside our home. The copper tubes of the evaporator receive the depressurized cold liquid refrigerant from the expansion valve and when indoors all blows over the cold coils, the heat from inside the home gets absorbed by this cold refrigerant.

This is because of the second law of thermodynamics which states that: heat flows naturally from a hot to a cold place. As this cold liquid refrigerant absorbs heat from the indoor air, it starts to evaporate to form a vapor, and thus, the refrigerant in this evaporator unit absorbs heat from our home and converts it into vapor and as a result, our home environment loses heat and cools down. This fan circulates the cold air from this coil surface for the cooling effect.

Now, this hot gaseous refrigerant after absorbing heat again goes through the compressor. Thus, the process is repeated continuously in a closed loop and the air conditioner keeps cooling our home continuously.

 

That was the working of an air conditioner.

Stay tuned, Bye.

Power Amplifiers: Explaned.

 

Power Amplifier:

            A power amplifier is an electronic device that's designed to raise line level signals to speaker level.

Working:

Instruments and microphones produce very low output power often just a few millivolts and this is nowhere near strong enough to drive a speaker. A free app is used to increase instrument or mic levels to line level at 0.316 or one points to three volts. Much more robust but, still not enough to drive a speaker. A power amplifier takes that line-level signal and increases it to speaker level.

So, as an example, what this means a thousand watts of power into 8 ohms requires around 90 volts at about 11 amps of current. That's a much stronger signal than you get out of an instrument or out of a preamp. So, a power amplifier is doing a tremendous amount of heavy lifting. In the system, a power amplifier might be a standalone device; such as a rack-mountable power amp used to drive TA speakers or onstage monitor wedges, or even studio monitors.

A power amplifier could be integrated into a device such as the power amp section in a guitar amplifier or the power amplifier built into an active studio monitor or a powered PA speaker. Originally, power amplifiers used vacuum tubes to increase the level of signals, and many guitar amplifiers as well as some hi-fi audio file systems still use vacuum tubes. Later, the tubes were replaced with transistors, which made power amps lighter and more compact, less expensive, and more durable. Traditional power amplifiers have long used linear technologies or designs, where tubes the transistors are used as valves. That controls the amount of power produced. In simple terms, the audio signal feeds on one side of the tube or transistor, and power from the AC wall outlet comes on the other side of the tuber. Transistor uses the incoming wall voltage to increase the level of the signal, where it can drive a speaker. There's a linear relationship between the analog incoming signals. The power voltage, and the analog speaker level output signal.

Today, many power amplifiers use Class D technology is also known as switch mode. Class D utilizes pairs of power transistors that work together to produce a square wave. This square wave is modulated by the incoming audio signal to create the output signal. At the speaker level, a technique known as pulse width modulation Class D is much more efficient than linear. And the way, in which it's implemented means that amplifiers can be made much smaller, lighter, and cheaper. While producing high levels of power, you may sometimes see a Class D power amplifier; referred to as a digital amplifier. But there's nothing digital about the process. The amplifier uses analog switching principles but not digital. Encoding and the signal are never converted to ones and zeros.

When choosing a power amplifier for a studio, monitor, or live sound system application, the key is to get enough clean power. In most cases, it's not too much power that blows or damages speakers but its distortion or clipping created in an overdriven and underpowered power after the cause of problems.

Power amplifiers are often used to enhance the tone and even dad distortion to the signal.

This is the working of a power amplifier.

Stay tuned,

Bye.

 

 

Batteries: Explained.

 

Can you imagine a world where all electrical appliances have to be plugged in? Flashlights, cellphones, and toys would be tethered to electrical outlets, making them clumsy, and inconvenient?

Batteries:

            Batteries provide portable and convenient sources of energy for powering devices without wires or cables. A dry cell is a common type of battery, used today. It basically converts stored chemical energy into electrical energy.

Basic structure:

In the most basic terms, a battery cell is made up of three components:

·         An anode

·         A cathode

·         The electrolyte

Working of a Battery:

In the dry cell, zinc is the anode. The graphite core is the cathode, and ammonium chloride paste acts as an electrolyte. Due to a chemical reaction within the battery, the anode builds up an excess of electrons. This causes an electrical difference between the anode and the cathode. The electrons want to rearrange themselves and displace the extra electrons in the cathode. However, the electrolyte ensures that the electrons cannot travel directly to the cathode.

When the circuit is closed with the help of a conductive path between the anode and cathode, the electrons can travel to the cat holder. This in turn provides power to any appliance placed along the way over time. This electrochemical process alters the chemical makeup. In the anode, and cathode, and eventually, they stop providing electrons.

This is how a battery dies. Batteries provide us with a mobile source of power that makes many model conveniences possible.

 

 

This is how a battery works.

Stay tuned.

Bye.

 

 

 

Speakers: Explained.

 Structure:

            The basic speaker design has a motor that drives the speaker back and forth; attached to a cone to translate this movement into pressure waves; that travel through the air.

Working Principle:

            Let's look at each part in depth. The motor, a voice coil, and a magnet work together. To form the speaker motor, the voice coil has a long section of thin copper wire wound many times around a heat-resistant cylinder, called the former. When electricity flows through the copper windings, it naturally generates a surrounding magnetic field. This phenomenon is what makes an electromagnet. An electromagnet can act just like a permanent magnet and yet incredibly, its polarity or the positive and negative pull orientation and magnetic intensity can be changed by altering the supplied electric current. It can instantly be made stronger or weaker, reversed, or turned off completely. A large permanent magnet or natural magnet surrounds the voice coil. This magnet has a top plate and a backing plate with a pull piece through the center. To focus the magnet's field through the gap, an intricate electrical signal flows through the voice coil windings, causing it to move back and forth. As its magnetic field pushes and pulls against that of the permanent magnet, this electrical current is a precise replica of the audio that was originally recorded. In fact, the entire sound is contained in this impossibly detailed signal the cone and suspension. The cone translates voice coil movement into waves that travel through the air. It has its own flexible suspension system which is made up of the surround on the outside and the corrugated spider. At its center, the dust cap keeps debris and unwanted material out of sensitive internal areas. Underneath the dust cap, the voice coil's copper leads attach to more flexible wires; called tinsel leads that can smoothly deform with intense speaker movement, recreating the whole symphony.

Producing of Sounds:

If a speaker only moves back and forth, how does it reproduce an entire symphony of sounds at the same time?

Let's look at basic sound wave operation. Air is an elastic medium meaning that it returns to its original shape. Once an acting force is removed, the speakers push and pull air molecules; making them ram into each other in a domino effect. This wave reaches and moves your eardrum which sends a signal that your brain interprets as sound. You could even say that hearing is just movement detection while it's often easier on paper to draw waves as a bouncy line.

In reality, sound waves are three-dimensional areas of high and low pressure. When we turn up the volume, the speaker pushes harder; sending more forceful waves through the air. The sound waves pushing force is its amplitude. To make high and low sounds, the speaker vibrates faster or slower. The wave rate is its frequency which is measured in hertz or in musical terms, its note pitch from waves to music. A musical instrument produces a unique waveform when played. Just one note has low mid and high-range vibrations; combined into a complex sound wave. The most apparent frequency of a vibrating guitar string may be a G-note and yet many smaller twitches and movements travel through the string at the same time; producing tones that your ear also detects.

One speaker can handle the whole sound like earphones. For example, in large spaces where sound waves need to travel further, some audio setups divide specific frequency ranges between specially designed speakers. A speaker intended for low and slow frequencies has a much different design than speakers made for high and fast frequencies.

 

Stay tuned.

Bye.

 

Voltage Regulators: Explained.

Introduction:

    In the world of electronic circuit design, the selection of the right voltage regulator is one of the most important decisions. Virtually, every product that runs on DC power employs voltage regulation.

                                        

Voltage Regulators:

    As the name indicates, voltage regulators take a variable or unstable input voltages and convert them to higher or lower constant output. That matches the voltage and current needs of an electronic circuit. Basic regulators of the linear IC type regulators simply drop down the source to the desired level and shed the rest as heat while the others such as the switching type are more efficient. Simply stated, rapidly switching a voltage input on and off results in an averaged voltage output, depending upon switching frequency. A wide range of voltages is possible from a single source. Some regulators employ additional features to handle large voltage spikes, reverse polarity protection, or remove unwanted signal noise, automotive alternators.

For use in electrical systems and charging the vehicle's battery, most alternators employ a built-in AC to DC rectifier and a robust voltage regulator that is capable of delivering 13.5 to 14.5 volts DC above 100 amps. Each device in the electrical system may have its own voltage regulator depending on its specific needs. Common voltages are 12 volts DC for lighting and accessories and 5 volts DC for sensors and control modules. 

Types:

Linear regulators use a transistor that is controlled by feedback from a differential amplifier circuit and a reference voltage to control the output voltage. They may feature fixed or adjustable output. Output current is determined by the input current minus circuit operation losses. Linear regulators are simple to add and give a fast response time but are not very efficient. The output of a linear regulator is always lower than the input and drops out if the input voltage is too low. 

Switching regulators are very efficient but can be difficult to design. As mentioned, earlier switching regulators use controllers to rapidly connect and disconnect either the positive or negative component of the source voltage from the rest of the converter circuit to produce desirable changes in voltage and current. A feedback loop from the output to the controller helps to determine the switching rate. The arrangement of inductors, capacitors, and diodes in basic switching converters determines if the output voltage is increased or decreased.

Buck-boost converters can increase or decrease voltage but

reverse the polarity.

Fly-back transformers increase the voltage to 

very high levels but at very low current by collapsing the field of an energized coil much like the ignition system in some

automobiles.

These are the basic functionality, types, and common

applications of voltage regulators. 

Stay tuned. Bye.