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Kategori: SCIENCE

  • Understanding How Processors and Transistors Perform Logical Operations

     

    Today, we will delve into the working principles of processors and explore how microcontrollers use transistors to perform logical operations. Along the way, we’ll build logic circuits to understand the fundamental functions of transistors. Finally, we’ll design an adder circuit capable of adding two 8-bit numbers to consolidate our understanding.

    Processors are often described as devices that execute given commands. However, the electrical processes performed by the transistors within these devices are rarely discussed in detail. In this article, we will start from the most basic concepts and work toward understanding how processors operate. Grasping these concepts is crucial in the fields of electronics and computer science.

    The Basic Structure of Computers and Processors

    Computers can be thought of as relatively simple calculators. They perform complex operations by breaking them down into many smaller steps. Historically, such calculations were carried out using mechanical machines. These machines relied entirely on physical movements for their operations. With technological advancements, mechanical components were replaced by relays, vacuum tubes, and eventually, transistors.

    The Harvard Mark I is a prime example of these early computers. The Mark I was programmed using punched cards and could perform only three additions or subtractions per second. Multiplication took six seconds, while division required 16 seconds. These machines were large, consumed a lot of energy, and had reliability issues. Vacuum tubes improved speed to some extent but remained large and fragile.

    The invention of transistors made electronic computers smaller, faster, and more reliable. Transistors are electronic switches that consume low power and can switch on and off rapidly. The fundamental working principles of processors rely on organizing these transistors into logical gates.

    How Transistors Work

    Transistors are three-terminal semiconductor devices that act as electronic switches. When an electrical signal is applied to the control terminal, the transistor allows current to flow between its other two terminals. If no signal is applied, the transistor prevents current flow. These two states represent the digital values of “1” and “0” in electronic systems:

    • “1”: Electricity is present, and the transistor is on.
    • “0”: No electricity, and the transistor is off.

    In processors, information is represented in binary form as bits. A bit can have a value of either “0” or “1.” Multiple bits are combined to work with larger numbers. For example, an 8-bit processor can handle values ranging from 0 to 255.

    Logical Functions of Processors and Logic Gates

    The fundamental building blocks of processors are logic gates. These gates consist of transistors and generate specific outputs based on their input signals. Here are the three most basic types of logic gates:

    NOT (Inverter) Gate:

    • Inverts the input signal.
    • If the input is “1,” the output is “0,” and vice versa.

    AND Gate:

    • The output is “1” only when all inputs are “1.”
    • For all other input combinations, the output is “0.”

    OR Gate:

    • The output is “1” if at least one input is “1.”
    • If all inputs are “0,” the output is “0.”

    These gates are combined in processors to execute complex operations. For example, in an AND gate with two inputs, the output is “1” only when both inputs are “1.”

    Constructing Logic Gates with Transistors

    Using transistors, we can construct these logic gates:

    • NOT Gate: A single transistor is used to invert the input signal.
    • AND Gate: Two transistors are connected in series, and the output is “1” only if both inputs are “1.”
    • OR Gate: Two transistors are connected in parallel, and the output is “1” if at least one input is “1.”

    These gates serve as the foundation for more complex circuits. For instance, an OR gate can be used to light up an LED whenever one of its inputs is active.

    Practical Applications of Logic Gates

    Logic gates can be used to design more sophisticated circuits. Examples include:

    • NOR Gate: Combines an OR gate with a NOT gate to invert the output.
    • NAND Gate: Combines an AND gate with a NOT gate to invert the output.
    • XOR (Exclusive OR) Gate: Produces a “1” output only when the inputs are different.

    These gates are essential for implementing decision-making processes in electronic systems.

    Designing Adder Circuits

    One of the primary functions of processors is performing addition. The circuits designed for this purpose are called adder circuits.

    Half Adder:

    • Performs addition on two bits.
    • Composed of an AND gate and an XOR gate.
    • Outputs both the sum (SUM) and carry (CARRY).

    Full Adder:

    • Includes an additional input for the carry from the previous bit.
    • Composed of two AND gates, one OR gate, and two XOR gates.
    • Handles more complex additions.

    Multiple full adders can be connected to add multi-bit numbers. For instance, eight full adders can be used to add two 8-bit numbers.

    The 8-Bit Adder Circuit

    An 8-bit adder circuit uses one full adder for each bit of the input numbers. The first adder does not require a carry input, but subsequent adders process the carry from the previous adder. This system performs operations in binary arithmetic.

    Example:

    • Operation: 68 + 96
    • Binary Representation:
      • 68 = 1000100
      • 96 = 1100000
    • Result:
      • 164 = 10100100

    These calculations can be performed millions of times per second using logic gates.

    Role of Logic Gates in Processor Development

    The evolution of processors has been driven by the miniaturization of transistors and the optimization of logic gates. Modern processors contain billions of transistors and can execute billions of operations per second. The ability to design such small and efficient logic gates has significantly improved the speed and capacity of computers.

    Understanding how processors and microcontrollers work requires an understanding of how transistors are organized into logic gates. These systems form the foundation of digital electronics and underpin modern technology. Learning how logic gates operate is essential to understanding how processors execute complex tasks.

  • The Fundamentals of the Brain’s Extraordinary Mechanism

     

    The human brain’s working system is a miraculously designed, complex, and fascinating structure. In just one cubic millimeter of the brain, there are 4 kilometers of neural pathways. Across the entire brain, the total length of these pathways reaches an incredible scale, considering the brain’s size. Moreover, within this dense and intricate system, no “traffic accidents” occur, demonstrating the efficiency of the brain’s operations
    .
    The speed of thought in the brain is approximately 2.8 million kilometers per second, an astonishing figure that far surpasses the speed of light. Each neuron in the brain can perform 10^16 operations per second, revealing an extraordinary processing capacity. The brain is composed of about 100 billion neurons, supported by 1.5 trillion logistical cells. Each neuron serves a unique function, emphasizing the unparalleled complexity of the brain.

    Traffic and Neuronal Communication
    Within the brain, this complex system operates in perfect harmony. For example, when a thought is formed, there is constant “traffic” between neurons. One neuron essentially asks another, “What do you think?” and this communication occurs within a hierarchical framework. There are no disruptions in this process; all cells communicate seamlessly with one another. If disruptions occur, problems like epileptic seizures or vascular blockages might emerge, 
    highlighting the brain’s extraordinary functional capacity.Studies on the brain have made it possible to visualize thought processes. For instance, when a person is thinking, the brain’s activity can be observed through color-coded imaging. This coloring helps us better understand how cells interact with one another. Recording the brain’s frequency during thought processes represents a major step in understanding how the brain works. The incredibly high speed and processing capacity of neurons underscore the brain’s vast potential.

    The Brain’s Renewal Process

    The brain has a self-renewing structure. When a person thinks, speaks, or performs any action, new pathways are formed between neurons. This process allows the brain to continuously learn and expand its capacity. For instance, when a person begins learning a new language, new connections between neurons are established, enhancing their linguistic skills.The human brain can find solutions to all kinds of challenges. If an individual puts in the effort to stimulate their brain, the brain responds accordingly. The brain must remain constantly active, as inactivity can lead to functional decline. For instance, conditions like Alzheimer’s are believed to be linked to inactivity. Keeping the brain active plays a critical role in preserving mental health.

    Einstein and the Connection to Quantum Physics

    Research on the brain often intersects with fundamental principles of physics. Renowned physicists like Albert Einstein and Niels Bohr worked on quantum mechanics to understand the behavior of subatomic particles. Bohr, for example, described the electrons orbiting the atom as a miraculous system of perfect order, which he attributed to divine creation. Such studies help us gain deeper insights into the brain’s complexity and the capacity of the human mind.

    Future Technologies and the Brain

    Advancements in brain research may pave the way for technologies capable of fundamentally transforming human life. For instance, systems that record thoughts via electromagnetic fields or lenses that allow us to see distant objects with remarkable clarity are being developed. These technologies demonstrate that only a fraction of the brain’s potential has been uncovered.In the future, systems capable of directly recording and analyzing human thoughts might become a reality. This could enable more efficient use of the brain’s capacity. For example, when contemplating a building, one might observe details like its cement or iron content without any additional tools. Such technologies have the potential to make human life easier and more effective.

    The Capacity of the Brain

    Research on the brain’s capacity reveals its astonishing potential. The human brain can store information equivalent to the number of atoms in the universe. This demonstrates the brain’s virtually limitless capacity for learning. However, to fully utilize this capacity, the brain must remain constantly active. Leaving the brain idle can lead to mental decline and diseases.

    Changing Habits and the Brain

    The flexibility of the brain makes it possible to change habits. The brain can renew itself by learning new information and forming new pathways. For example, if a person wants to replace their morning coffee routine with a walk, the neurons in their brain restructure to support this new behavior. This process illustrates the brain’s constant adaptability and capacity for change.The brain’s flexibility gives people the opportunity to change their habits and adopt a better lifestyle. However, this process requires patience and determination. For the brain to adapt to these changes, individuals must allow themselves time and consistently practice their new habits. The human brain is one of the most complex and impressive systems in the universe. Its extraordinary capacity and operating principles offer great opportunities both scientifically and personally. Keeping the brain active, learning new information, and changing habits play a vital role in maintaining mental health and unlocking one’s full potential.

  • Fundamentals of Quantum Mechanics

     

    When learning quantum mechanics, it is crucial to have a strong understanding of fundamental mathematical concepts such as vector spaces, linear algebra, eigenvectors, and operators. These concepts form the mathematical foundation of quantum mechanics. Among these, the Schrödinger equation is one of the most fundamental elements of quantum mechanics. The Schrödinger equation is a fundamental law of nature and is not derived from anything else. Similar to Newton’s second law, it is directly accepted as a fundamental law of nature.

    When studying the Schrödinger equation, it is essential to understand how its solutions are interpreted probabilistically and how Max Born statistically interpreted the wave function. Using the Schrödinger equation, one must learn how to measure physical quantities such as the position, momentum, or angular momentum of a particle. Understanding Heisenberg’s uncertainty principle is also of critical importance in this process.

    Wave Function and Superposition Principle

    Quantum mechanics is fundamentally built on wave mechanics. However, more specifically, it can be referred to as wave packet mechanics. Wave packets are formed by the superposition of many waves, and this phenomenon is known as the superposition principle. The superposition principle arises from the fact that the Schrödinger equation is mathematically a linear equation.

    Solutions to the Schrödinger Equation

    Understanding the solutions to the Schrödinger equation forms the foundation of quantum mechanics. Typically, studies begin with time-independent solutions, which are examined in one dimension. One of the first problems studied is the particle-in-a-box problem. This problem examines the quantum mechanical behavior of a particle confined within a box with high-energy potential barriers on both sides.

    Another important problem is the harmonic oscillator problem, which examines the quantum mechanical behavior of a particle attached to a spring. The harmonic oscillator serves as the foundation for many physical concepts, ranging from quantum field theory to statistical physics.

    The three-dimensional solutions of the Schrödinger equation are used to understand the structure of the hydrogen atom. Solving the hydrogen atom using the Schrödinger equation is one of the most elegant applications of quantum mechanics. Additionally, understanding the concept of spin is a critical step in advanced quantum mechanics. Spin is a quantum mechanical property with no classical counterpart.

    Formalism in Quantum Mechanics

    Understanding the formalism of quantum mechanics is essential for delving deeper into the subject. The Schrödinger equation is a complex equation, and there is no general solution for many potentials. Therefore, it is beneficial to learn approximation methods such as perturbation theory and variational principles. These methods are used to find approximate solutions to the Schrödinger equation.

    Importance of Quantum Mechanics

    Quantum mechanics forms the cornerstone of modern physics and is one of the greatest scientific achievements of the 20th century. Theories like quantum electrodynamics present predictions that are verified to 18-19 decimal places, showcasing one of humanity’s greatest intellectual accomplishments. Additionally, quantum mechanics is the first non-classical physics theory, representing a new way of thinking.

    Methods for Studying Quantum Mechanics

    When studying quantum mechanics, you must move away from the thought processes of classical mechanics. This requires adopting a new formalism and way of thinking. Initially, focus on learning how to perform quantum mechanical calculations, and later, delve into the deeper meanings of these calculations. During this process, discussing the concepts with your peers and instructors can significantly enhance your understanding.

    Quantum mechanics holds a pivotal place in the study of physics. Understanding this subject allows you to grasp the foundations of modern physics and prepare for advanced research. Through patient and consistent study, you can deeply learn the concepts of quantum mechanics and achieve success in this field.

  • What is Glass?

     

    Glass, whose primary material is sand, is one of the materials widely used in daily life for various functional purposes. Sand, used in the production of glass, is among the most abundant substances found in nature. The most significant and unique feature of glass is its transparency. So, what is glass? In the simplest terms, glass is the transparent material produced by processing a mixture of substances such as lime, sand, and soda through various procedures.

    What is sandy glass? It refers to glass obtained by melting only sand, also known as pure silica glass. However, this material, produced solely from sand, tends to be highly fragile. Glass is used in various applications, including household windows, drinking glasses, and automobile windows, which are indispensable in everyday life.

    What Materials Make Up Glass and How Is It Produced?

    The production of glass requires careful attention and the proportional and accurate use of its component mixtures. What is glass made of? During its production, soda is added to the mixture of sand and lime to reduce the melting temperature and increase the durability of the glass. To prevent chemical degradation and resistance to water, minerals such as dolomite, limestone, and feldspar are also included in the mixture, which is referred to as the “batch.”

    How is glass made after forming the batch? Raw materials resembling glass fragments are added to this mixture, which is then melted in a furnace. When the batch is melted in a glass furnace at a temperature of 1500 °C, it transforms into a fluid, amber-colored material known as soda-lime glass. The molten glass is then cut appropriately and subjected to automatic blowing and pressing in machines. A double-blowing technique may also be applied. After blowing and pressing, the material undergoes molding to be shaped into bottles, glasses, jars, and similar products. These glass products are then cooled, subjected to meticulous quality checks, and defective items are identified and separated, completing the production process.

    What Are the Types of Glass?

    The following headings detail various types of glass:

    1. Soda-Lime Glass
      This is the earliest discovered type of glass. Approximately 90% of the glass produced globally consists of soda-lime glass. Soda-lime glass is obtained using CaO. Due to its ease of softening, it is inexpensive. Its low cost makes it widely used in many areas, with windows being its most common application.

    2. Borosilicate Glass
      This type of glass is created using SiO2 and boron oxides, which form a mesh-like structure. Borosilicate glasses feature a high softening point, making them highly resistant to temperature fluctuations.

    3. Lead or Crystal Glass
      Lead glass is obtained using PbO and has excellent workability. Glass containing 24% PbO is also referred to as crystal glass due to this property.

    4. Silica Glass
      With 96% silica content, this type of glass is notable for its high transparency. Its ability to transmit UV rays at high levels makes it a preferred material for manufacturing germicidal lamps and UV lamps. However, its high cost limits its use in everyday life.

    5. Aluminosilicate Glass
      This glass contains over 20% alumina, along with small amounts of boron, lime, magnesia, and minimal alkalis. It is challenging to melt and process. Due to its high softening point, it is used in manufacturing components that come into contact with flames, such as combustion tubes      .

  • The Evolution of Automatic Transmissions

     

    Initially, automatic transmissions were considered a luxury due to the comfort they provided and their higher cost. Today, while manual models are still preferred as a more economical alternative, vehicles equipped with automatic transmissions have become quite common. Now more accessible, this type of transmission was first developed in 1921 by steam engineer Alfred Horner Munro. Due to his expertise, Munro designed the device to use compressed air instead of hydraulic fluid. Although it was not commercially utilized and lacked sufficient performance, this design played a significant role in laying the foundation for the development of modern automatic transmissions. The first automatic transmission operating with hydraulic fluid was developed in 1932 by José Braz Araripe and Fernando Lehly Lemos, who sold their design to General Motors. This technology was used in GM tanks during World War II and was marketed for personal use with the slogan “battle-tested.” The first mass-produced vehicles to feature automatic transmissions were the 1940 Oldsmobile and Cadillac models with the Hydra-Matic option. Following Cadillac, brands like Pontiac, Bentley, Rolls-Royce, Kaiser, Nash, and Hudson also adopted automatic transmissions.

    Types of Automatic Transmissions

    Fundamentally, automatic transmissions allow drivers to operate vehicles without using a clutch pedal or manually shifting gears, thereby reducing the number of tasks requiring attention. This not only enhances focus but also reduces workload, providing a more comfortable driving experience. However, there are several types of automatic transmissions beyond just one or two alternatives.

    Fully Automatic Transmission
    Fully automatic transmissions can change gears without human intervention, adjusting shifts based on the vehicle’s speed, load, and road conditions. Also known as torque converter transmissions, they handle most tasks autonomously, eliminating the need for a clutch pedal. Additionally, the gear selector in automatic vehicles differs from that in manual ones. Instead of gear levels, options are available to park the vehicle, move it in reverse, set it to neutral, and operate in standard or sport modes.

    Single-Clutch Automatic Transmission

    A single-clutch automatic transmission can be described as a manual transmission system that automatically shifts gears. Therefore, vehicles with single-clutch systems are often referred to as semi-automatic transmissions. They are frequently chosen for the comfort they offer compared to manual transmissions. Single-clutch transmissions are particularly noted for their fuel efficiency.

    Dual-Clutch Automatic Transmission

    Known in the literature as Dual Clutch Transmission (DCT), dual-clutch systems are among the most commonly used types in automatic vehicles. Models equipped with dual-clutch transmissions provide a smooth driving experience at both high and low speeds, allowing for seamless gear transitions. The system also permits semi-automatic operation and positively impacts fuel consumption. In dual-clutch transmissions, which can shift gears faster than other gear systems, separate clutch mechanisms exist for odd and even gear sets.

    CVT Transmission

    Continuously Variable Transmission (CVT) systems are designed to offer lower fuel consumption and higher performance. This mechanism consists of two pulleys connected by a belt or chain. During driving, gear adjustments are made based on the pulleys’ expansion and contraction. The term “continuously variable” is used because, unlike fixed-gear transmissions, CVT systems do not have specific gear levels. Instead of shifting to a specific gear like first or second, the vehicle adjusts to the required gear ratio based on current needs, thereby regulating speed. Since there are no fixed gear levels, technically, gear shifts are not felt in CVT systems. One disadvantage of CVT transmissions is the high operating noise they produce. When accelerating, the transmission holds the vehicle at the highest RPM and maintains that level until the desired speed is reached.

  • How Do Air Conditioners Work?

     

    How Do Air Conditioners Cool?
    Air conditioners utilize the evaporation and condensation properties of R22 or R410 gas to expel heat from the environment. In split air conditioners, the gas passing through the indoor unit absorbs the heat in the environment and evaporates. This process cools the environment. The evaporated R22 gas reaches the outdoor unit, where it condenses and releases the absorbed heat outside. During this process, only the fan motors in the indoor and outdoor units and the compressor circulating the gas consume electrical energy.

    How Do Air Conditioners Heat?
    Heat pump air conditioners, as the name suggests, use external heat to warm the environment instead of directly converting electrical energy into heat. These air conditioners perform heating through the condensation and evaporation of R22 gas, just as they do for cooling. For heating, the gas passing through the outdoor unit absorbs heat from the outside and releases it into the indoor environment upon condensation in the indoor unit.

    The efficiency of air conditioners in heating or cooling depends on external and internal air temperatures. As the outdoor air temperature increases, the cooling performance decreases, and as it decreases, the heating performance declines. Heat pump air conditioners are particularly economical when the outdoor air temperature is around 7°C. For this reason, they are preferable in mild winters, spring, and autumn. The compressor absorbs heat from the evaporator, compresses it, and sends the high-pressure hot refrigerant gas to the condenser. The gas condenses into a liquid in the condenser. The expansion valve converts this liquid refrigerant into a low-temperature, low-pressure liquid-gas mixture. This low-temperature refrigerant enters the evaporator. As the liquid evaporates in the evaporator, it absorbs heat from the airflow passing through the evaporator fins. This process is repeated continuously.

    Main Components in Cooling Cycle:

    Compressors
    Compressors are the heart of the system, compressing the refrigerant gas from low pressure and temperature to a higher pressure and temperature, enabling it to flow through the condenser. There are three main types:

    • Reciprocating Compressors
      The most commonly used type, ranging from small single-cylinder models to large 16-cylinder ones.

    • Rotary Compressors
      Quieter and more compact than reciprocating compressors, they consume less energy but are more prone to breakdowns and often irreparable. These compressors use rotational movement instead of pistons, commonly found in devices with low power requirements.

    • Scroll Compressors
      These use a unique mechanism involving two interlocking spirals. One spiral remains stationary while the other moves in an orbital path, compressing the refrigerant. They are efficient, quiet, and compact but costly and non-repairable. Proper installation and protection mechanisms are essential to avoid damage.


    Heat Pumps:

    Heat pumps transfer heat from one environment to another, just like cooling machines. However, they can transfer heat in two directions. In addition to typical components like evaporators, condensers, compressors, and expansion valves, heat pumps include a four-way valve.
    In winter, heat pumps absorb heat from outside and transfer it indoors, while the process reverses in summer.

    Types of Heat Pumps:

    • Air-to-Air Heat Pumps: Transfer heat between indoor and outdoor air, commonly seen in window and split air conditioners.
    • Air-to-Water Heat Pumps: Use air as a heat source in winter and water in summer for heat transfer.
    • Water-to-Water Heat Pumps: Designed to use water sources such as wells, lakes, or rivers for heating and cooling.
    • Air-to-Ground Heat Pumps: Similar to air-to-water systems but use the ground as the heat source or absorber.

    These applications are less common compared to other types.

  • how does a calculator work ?

     

    Calculators are indispensable tools in our daily lives, performing instantaneous calculations with remarkable speed. This efficiency is largely attributed to advancements in electrical engineering. However, early calculators were far simpler, relying solely on mechanical components.
    The abacus, often considered the first calculator and computer, enabled users to perform basic arithmetic manually. In subsequent centuries, devices like the Pascaline emerged, capable of addition and subtraction. Although primitive by today’s standards, these inventions represented significant progress at the time. Later, Gottfried Wilhelm von Leibniz developed the Leibniz Wheel, a device that could perform all four basic arithmetic operations.
    A pivotal figure in computing history is Alan Turing. During World War II, Turing’s exceptional technological intellect led to the development of machines that deciphered Nazi codes, notably with his creation, “Christopher.” His contributions not only influenced the war’s outcome but also laid foundational principles for modern computing.
    Over the years, continuous research and development have led to the advanced calculators we use today. Modern electronic calculators differ from their mechanical predecessors primarily in their use of binary (base-2) number systems, employing sequences of 0s and 1s. Internally, they consist of components such as input units, output units, and magnetic fields, processing signals through these elements. This design enables calculators to perform hundreds of thousands of logical operations per second. It’s important to note that computers and calculators execute only the commands they are programmed to perform, delivering precise results without deviation.
    As technology continues to advance, calculators may evolve further, potentially acquiring capabilities beyond their current functions. Reflecting on the development of such fundamental devices prompts us to consider the future innovations that await.

  • What is Digital Communication?

     

    With the advancement of communication technologies, modern digital communication systems have replaced analog modulation-based systems. Digital communication systems offer significant advantages over analog systems, including:

    • Pulse Modulation Power Efficiency: In pulse modulation, the transmitted power is concentrated into short pulses, unlike the continuous transmission in analog modulation.

    • Multiplexing Capability: The gaps between pulses can be filled with pulses from other message signals, allowing multiple information signals to be sent over a single communication system.

    • Advancements in Integrated Circuit Technology: Rapid developments in integrated circuit technology have made the implementation of digital communication circuits increasingly easier.

    • Improved Noise Immunity: Digital systems exhibit superior resistance to noise compared to analog systems.

    In digital communication systems, information is typically in an analog form, such as voice or images. The first step in digital communication is converting this information into digital pulses. These pulses are transmitted from the sender and then converted back into analog information at the receiver.

    Various modulation methods are used to prepare analog information for digital transmission, each with its corresponding demodulation system. Common digital communication systems include:

    • PAM (Pulse Amplitude Modulation): Modulates the amplitude of pulses to represent the information signal.

    • PCM (Pulse Code Modulation): Encodes the amplitude of the analog signal into a series of coded pulses.

    • PWM (Pulse Width Modulation): Modulates the width of pulses to convey information.

    • PPM (Pulse Position Modulation): Modulates the position of pulses relative to a reference to encode information.

    • ASK (Amplitude Shift Keying): Modulates the amplitude of a carrier signal to represent digital data.

    • FSK (Frequency Shift Keying): Modulates the frequency of a carrier signal to transmit digital information.

    • PSK (Phase Shift Keying): Modulates the phase of a carrier signal to encode data.

    • Delta Modulation: Encodes the difference between successive samples of the analog signal.

    • QPSK (Quadrature Phase Shift Keying): A form of PSK that uses four distinct phase shifts to represent data.

    Bit: A bit is an electrical signal representing binary information, typically with a digital ‘1’ indicating the presence of voltage and a digital ‘0’ indicating the absence of voltage. Each ‘1’ and ‘0’ in an information signal corresponds to one bit. Eight bits constitute one byte (B). For example, the signal ‘1001000011111010’ is 16 bits or 2 bytes.

    Bits Per Second (bps): The rate of information transmission is measured by the number of bits transmitted per second, denoted as bps.

    Baud: This term is commonly used to express the signaling rate of devices like modems. It represents the number of signal units transmitted per second. For instance, if a device sends information coded with 2 bits per signaling unit, 1 baud equals 2 bits.

    Baud Rate: The baud rate is the number of signal changes or symbols transmitted per second over a communication channel. In the RS-232 standard, which operates on a one-bit-per-signal-change principle, a baud rate of 9600 corresponds to transmitting 9600 data bits per second. If each bit requires two signal changes (as in NRZ coding), a baud rate of 9600 would result in transmitting only 4800 bits per second.

    Bit Error Rate (BER): In digital communication, BER refers to the ratio of incorrectly received bits to the total number of transmitted bits.

    Channel: The medium through which information is sent to the receiver is called the channel. In modern data transmission, twisted pair cables (UTP-STP), fiber optic cables, and wireless communication are commonly used.

    Channel Capacity: This term denotes the maximum number of bits that can be transmitted through a channel.

    Noise: Various types of noise and their formulas are discussed in analog communication topics. In digital communication, noise can be categorized into two groups: internal (system-generated) and external (environmental).

    Encoding: Digital encoding defines how data bits are represented in the physical communication medium. An effective digital encoding technique should meet the following criteria:

    • Bandwidth Efficiency: Utilize minimal bandwidth to allow multiple signals to be transmitted simultaneously over the communication channel.

    • Low DC Level: Maintain a low direct current (DC) level to reduce attenuation over long distances, as high DC levels are more susceptible to signal degradation.

    • Polarity Independence: Ensure the signal is not affected by the physical characteristics of the transmission medium, such as when transmitted over a two-wire cable.

    Encoding Methods:

    • NRZ (Non-Return to Zero): In this basic method, ‘0’ bits are represented by 0V, and ‘1’ bits by a positive voltage.

    • RZ (Return to Zero): ‘0’ bits are represented by 0V, while ‘1’ bits are represented by a positive voltage for the first half of the bit duration and 0V for the second half.

    • NRZI (Non-Return to Zero Invertive): A ‘0’ bit is represented by no change in voltage. A ‘1’ bit is represented by a change in voltage: if the previous voltage was 0V, it changes to positive; if it was positive, it changes to 0V.

    • AMI (Alternate Mark Inversion): ‘0’ bits are represented by 0V, while ‘1’ bits are represented alternately by positive and negative voltages.

    • PE (Phase Encode, Manchester): ‘0’ bits are represented by a positive voltage in the first half of the bit duration and a negative voltage in the second half. ‘1’ bits are represented by a negative voltage in the first half and a positive voltage in the second half.

    These encoding methods are fundamental to digital communication systems, each offering unique advantages depending on the application and transmission requirements.

  • Analog Communication Explained in a Comprehensive Manner

    Communication:
    The exchange of meaningful information is defined as communication (Exchanging Information). In today’s world, the development of internet communication and electronic media has given the concept of communication a global meaning, turning it into “global exchanging of information.” Communication has technical, economic, social, and cultural dimensions. To achieve full, uninterrupted, and 100% communication, barriers to communication must be overcome.

    Communication Barriers:

    • Distance
    • Attenuations in the transmission medium
    • Insufficient financial resources for following technological developments
    • Language and cultural differences

    Providing the necessary technical equipment for communication over long distances falls under the domain of telecommunications. 


    Elements of a Communication System

    Transmitter:
    Electronic circuits that encode or shape the signal to be transmitted into a form suitable for the medium. For example:

    • Radio transmitters: 1000 W–10 kW
    • Wireless transmitters: 2W–600W
    • Base stations: 25W
    • Mobile phones: 3W (500 mW in standby mode)

    Transmission Medium:
    The medium that carries the signal encoded by the transmitter. Transmission media can be divided into two types:

    • Guided (cabled)
    • Unguided (wireless/natural mediums)

    Guided Transmission Media:
    Includes mediums such as copper cable, twisted pair cables, coaxial cable, fiber-optic cables, and microwave guides.

    Unguided Transmission Media:
    Natural mediums like air, water, and vacuum.

    Disturbances and Noise in Transmission Media:

    • Signal Attenuation: As communication distance increases, the signal weakens, and insufficient energy reaches the receiver.
    • Signal Distortion: Caused by different frequencies in the signal being attenuated differently as they propagate.
    • Delay Distortion (Dispersion): Results from different frequencies or light rays in fiber-optic cables taking different paths, reaching the target at varying times.
    • Noise: Any energy that disrupts the signal and unpredictably enters the system (e.g., sunlight, fluorescent lamps, motor ignition systems).

    Types of Noise:

    1. Interference: Undesired signals entering the system and disrupting the main signal.
    2. Thermal Noise: Arising from free electrons in components like resistors and transistors due to ambient temperature (also known as Johnson noise or white noise).
    3. Intermodulation Noise: Harmonic frequencies of signals combining, leading to noise.
    4. Crosstalk: Signals in adjacent cables interfering with each other.
    5. Shot Noise: Noise originating in transistors.
    6. Impulse Noise: Noise caused by operational factors like electrical motors, ignition systems, or electromechanical relays.

    Bell and Decibel:

    As signals travel along a transmission line, they weaken. Repeaters amplify these signals back to the line. The logarithmic measure of this attenuation or amplification is termed a “Bell,” named after Alexander Graham Bell.


    • Definition: When the amplitude of a carrier signal is varied in proportion to the information signal, it results in amplitude modulation.
    • Double Sideband Amplitude Modulation (DSB-AM): A modulator circuit produces amplitude modulation.

    Radio Receivers

    Superheterodyne Receiver:
    Receives electromagnetic signals, amplifies them, and sends them to a speaker. Key properties include:

    1. Sensitivity: Ability to capture and amplify weak signals.
    2. Selectivity: Ability to filter out and isolate the desired signal from others.

    Electronic Tuner:
    A circuit composed of RF amplifiers, mixers, and local oscillators. It selects, amplifies, and extracts intermediate frequencies. If varicap diodes are used, it is termed an electronic tuner.


    Frequency Modulation (FM):

    • Need: To address the signal-to-noise ratio problems at high power levels in AM systems. FM circuits include limiter circuits, PLL synthesizer circuits, and emphasis circuits.
    • Definition: The frequency of the carrier signal changes according to the amplitude of the information signal.

    Advantages of FM:

    1. Higher sound quality due to reduced noise.
    2. Greater immunity to noise compared to AM.
    3. Capture Effect: FM systems prioritize stronger signals on the same frequency.
    4. Utilizes PLL synthesizer circuits.

    Disadvantages of FM:

    1. Requires significantly larger bandwidth.
    2. More expensive circuits.
    Stereo Transmitters and Receivers
    The term “stereo” originates from a Greek word meaning “three-dimensional.” In modern usage, it creates a three-dimensional effect with a two-source sound system placed at a certain distance from the listener. Stereo receivers and transmitters are designed to separate or create two-source signals, respectively. Stereo coding is incorporated into FM transmitters between the sound circuit and modulator.

    Stereo coding procedures are standardized for compatibility with existing systems. A single-channel receiver can output both sound channels through one speaker, while a dual-channel receiver delivers stereo sound through two speakers.


  • How Does a Transformer Work?

     

    A transformer, or simply a “trafo,” is a machine used in alternating current (AC) systems to convert voltage through magnetic induction. Transformers have no moving parts, and the transformation is carried out without changing the frequency.

    Transformers are generally used in the transmission and distribution of energy. During the transmission of electricity from power plants to end users, voltage transformation and power loss occur in the lines. To minimize this loss, it is necessary to raise the voltage while keeping power constant. This means reducing the current. With transformers, intermediary stations can be set up before the energy reaches the end user, allowing the cross-sectional area of conductors to be reduced. This reduces losses and costs.

    Transformers are typically used to raise or lower voltage or current in an electrical circuit. In electronics, they are also used to connect amplifiers in different circuits or to convert DC (direct current) waves into higher AC (alternating current) values. Additionally, transformers in electronics are used to transmit specific frequencies.

    What Are the Characteristics of Transformers?

    Transformers consist of a core and two coils. This structure transfers electrical energy from one conductor to another. Voltage is applied to one of these two coils on the core, generating a magnetic flux. This magnetic flux undergoes continuous changes in direction and intensity.

    The magnetic flux induces voltage in the output coil. In summary, the voltage applied to both coils generates a magnetic field, which transfers energy to the other coil. If the output winding count in the transformer is higher than the input winding count, the output voltage will be greater than the input voltage.

    Purposes of Using Transformers
    Transformers can be used for multiple purposes and can be encountered in various fields. Generally, they are used for three different purposes:
    To increase or decrease the existing voltage or current,
    To protect multiple circuits with a common chassis connected to the same power line from short circuits,
    To ensure impedance matching.

    Where Are Transformers Used?

    Transformers can be used wherever electricity is used. They are found in many places where electrical energy exists and are available in various types and sizes depending on the working environment. Transformers are used in the distribution of electrical energy, power plants, and devices that draw energy from the network. In short, if alternating current (AC) is used in a location, a transformer is present. Transformers are available in various types. Now that you know what a transformer is, its features, purposes, and usage areas, you can also learn about its types.

    What Are the Types of Transformers?

    Transformers are classified based on various criteria, including the number of phases, core type, working environment, and method of increasing or decreasing voltage.

    The first transformer classification is based on the number of phases, divided into single-phase and multi-phase transformers:

    Single-Phase: These transformers have a single input winding, but the output winding may vary.

    Multi-Phase: These transformers have multiple input windings.
    Another category is based on core type. Transformers are classified into three main types according to core type: core type, shell type, and distributed type.

    Core Type: Core-type cores are used in high-power, high-voltage transformers because the insulation of windings is easier.

    Shell Type: In shell-type cores, windings are wound on the central limb. Unlike core types, these are used in low-power, low-voltage transformers.

    Distributed Type: These cores have a cross-shaped appearance. The windings are wrapped around the middle leg, resulting in minimal leakage flux, reducing idle working currents.


    Transformers can also be classified according to their purpose, with five different transformer types as follows:

    Auto Transformer: This type uses a single winding as both input and output, achieving high efficiency with a much smaller size compared to other types.

    Measuring Transformer: This type is used for measurement purposes in environments with high current and voltage levels.

    Step-Down Transformer: In this type, the output voltage is lower than the input voltage, reducing the electrical energy’s voltage. This is one of the most commonly used transformers.

    Step-Up Transformer: This type is the opposite of the step-down transformer. The output voltage in these transformers is higher than the input voltage.

    Isolation Transformer: The purpose of this type of transformer is to electrically isolate two circuits.

    The final type of transformer is categorized by its working environment, with various types available depending on the environment. Examples include underwaterr, underground, and indoor transformers.

    How Do Transformers Work?

    Transformers operate on a simple principle. An alternating current applied to the coil creates a time-varying magnetic flux on the magnetic core, inducing a voltage in the other coil. The ratio of turns between the primary and secondary windings determines the ratio of input to output voltage, providing upward or downward transformation of voltage.

    When an appropriate AC voltage is applied to the primary winding, the current passing through it creates a magnetic field in the core, which completes its circuit on the limb where the secondary winding is wound. According to the induction principle, when subjected to a variable magnetic field, voltage is induced at the ends of the conductive coil. In this scenario, the voltage applied to the primary winding and the magnetic field generated on the limb of the secondary winding induce an electromotive force (EMF) on the secondary coil. This electromotive force is often abbreviated as EMF. Through these methods, voltage is induced on the secondary winding via induction, even though there is no electrical connection between the primary and secondary windings. Auto transformers differ slightly, as they have an electrical connection between the windings since both the input and output circuits are wound on the same core.

    When an AC voltage is applied to the primary winding of transformers, a variable magnetic field is created. This magnetic field completes its circuit on the core, where the secondary winding is also located. The applied voltage to the primary winding continuously changes direction and intensity over time, resulting in constant changes in the magnetic field’s direction and strength. The alternating field cutting through the secondary winding induces an AC voltage in the winding.

    When a direct voltage is applied to the primary winding of transformers, a magnetic field is also generated, but it is static. Since the direction and intensity of this field do not change, no electromotive force (EMF) is induced in the secondary winding.

    In transformers, to change and stabilize the voltage with the conversion ratio, the winding taps are taken out. The number of output taps is calculated according to the voltage adjustment range. A 5% voltage adjustment is sufficient for distribution transformers, while adjustments up to 20% may be possible for long-distance, high-power, high-voltage transformers. In transformers, voltage adjustment can be made continuously or in steps by changing the transformation ratio. Stepped voltage adjustments can be made on-load or off-load. For such adjustments, a specially designed tap-changer switch is used.

    When adjusting voltage under load, care must be taken to prevent the disconnected winding taps from short-circuiting, as this would cut off power. A tertiary winding, parallel windings, a reactance coil, or resistors can be used for load adjustments.