Notes, summaries, assignments, exams, and problems for Electronics

Electromagnetic Waves

6. Wave: electromagnetic vibration propagating through space.

• Length (m): Distance from the beginning until it repeats.
• Width (m): Maximum height.
• Frequency (Hertz): Wave quantities per second.

Voice Transmission

7. Voice (microphone) → cable → electrical signal transmitter → antenna (emits waves) → wave → electrical signal → antenna captures → voice.

Am: Amplitude Modulated.
FM: Frequency modulation.

Digital Terrestrial Television (DTT)

8. Television is accessible to all with DTT, offering optional paid content.

• Eliminates image defects and snow effect.
• Improves picture quality and sound.
• Allows subtitle and language selection.
• Offers interactive and multimedia services.
• Enables real-time traffic, statistics, surveys,

Communication is the process by which a sender transmits a message to a receiver.

A sign is something (a set of sounds, a figure, a light) which suggests the idea of something else.

Schematic Diagram of Communication:

• Issuer: The one who prepares and sends the message.
• Receiver: The one who receives and interprets the message.
• Message: The information that the sender transmits.
• Context: The set of circumstances surrounding the communication.
• Code: The sign system used to develop the message.
• Channel: The medium that carries the message (visual, auditory).

Text: A complete message that is transmitted orally or in writing.

Classes of Texts:

According to the communicative intention, we can distinguish four types of texts:

• Informative: Aim to facilitate new

Textual Cohesion and Redaction Principles

To organize text and give it meaning in an essay, use textual markers. In a text, we must differentiate between the title, which indicates the subject of the text, and the division into paragraphs, which expresses a single idea. Sentences are groups of words separated by a full stop.

Exercise: Textual Connectors

Indicate what type of connectors are used and explain why they have been chosen. It is intended that their communicative intent is clearly reflected in the text through their use.

Pragmatic Application of Written Expression

The intentions of the issuer when writing a message can vary. These intentions are understood in accordance with the functions of language that prevail. These communicative intentions... Continue reading "Linguistic Analysis: Text Cohesion, Pragmatics, and Syntax" »

Understanding Control System Controllers

Core Components of a Control Loop

In a control and regulation system, we can distinguish the following elements:

• Transducers and sensors
• Comparators and error detectors
• Control and regulation elements
• Final elements or actuators

The controller is the 'brain' of a control loop. It is responsible for comparing a physical variable with the desired value (setpoint), interpreting the error or deviation, and acting to minimize or eliminate this error. While the controlled variable is maintained at the expected value, the controller does not act on the final elements. If the control variable deviates from the setpoint, the controller modifies the signal acting on the final elements to correct this deviation, continuing... Continue reading "Understanding Proportional, Integral, and Derivative Controller Actions" »

Decibel (dB) Calculations and Conversions

The decibel (dB) is a logarithmic unit used to express the ratio of two values of a physical quantity, often power or voltage. It is widely used in electronics, acoustics, and control theory.

• Power Gain (GdB): 10 · log (Po / Pi)
• Voltage Gain (GdB): 20 · log (Vo / Vi)

Common dB Conversions:

• dBm to dBW: dBW = dBm - 30
• dBµV to dBm (75 Ohm): dBµV ≈ dBm + 107
• dBµV to dBW (75 Ohm): dBµV ≈ dBW + 137

Note: Specific conversion values like +108.8 dB and +138.8 dB may apply to particular system impedances or standards.

Understanding Noise in Signal Systems

Noise refers to any unwanted signal that accompanies a useful signal, degrading its quality.

Types of Noise:

• External Noise: Originates from sources outside the

Lexical Morphology

A linguistic sign is an entity associated with two planes: a sequence of sounds (signifiers) and a mental image (meaning). These planes are indivisible.

Components of the Linguistic Sign

• Phoneme: The smallest unit of the linguistic sign without meaning on its own, but with distinctive value. They have no meaning alone but acquire it as part of a sequence. Example: /m + a + o/ → /p + a + o/
• Moneme: These are minimal units of meaning. An infix is a sound that serves as a liaison among other components of the word.

Lexemes

The lexeme is not always the unchanging part of a word (e.g., WIND - windy). What remains constant is the common concept, but phonetic irregularities may occur in the lexeme from one word family to another. Many... Continue reading "The Building Blocks of Language: Lexemes and Morphemes" »

Linguistic and Media Definitions

Journalistic Genres and Research Methods

Linguistic Features: Grave Accent and Closed Vowels

The concept of the grave accent and closed vowels relates to how letters represent different sounds. This includes the open letter to Sempra, letters, and one long closed e letters, or they may represent different sounds.

The Interview

The interview (often abbreviated as QE) is a journalistic genre involving a conversation or a dialogue between two people.

Structure of an Interview:

1. Presentation
2. Dialogue
3. Final Comment

The Journalistic Debate

The debate, a journalistic genre, exposes the views of several people who have spare questions, led by a moderator.

The Poll (Survey)

A poll is a set of questions prepared in order to know the... Continue reading "Key Concepts in Sociolinguistics, Journalism, and Global Languages" »

Interlanguage: A Unique Linguistic System

Interlanguage recognizes that L2 learners construct a linguistic system that draws, in part, on the learner’s L1 but is also different from it and also from the target language. It is a unique linguistic system and involves different premises.

Premises of the Interlanguage System

1. Mental Grammar: The learner constructs a system of abstract linguistic rules which underlies comprehension and production of the L2. This system is viewed as a mental grammar.
2. Permeability: The learner’s grammar is permeable. It is open to influence from the outside (e.g., through the input) and also from the inside (omission, overgeneralization, and transfer errors).
3. Transitional Nature: The grammar is transitional. Learners

Lesson 1

Hydropower Plants: Using the energy generated by the water stored in a swamp to a steep fall on the turbine that mechanically turns the electric generator, which produces electricity.

Nuclear and Thermal Power: Using steam at pressure on the turbines that drive the electric generator. In thermal power, steam is produced by combustion, while in nuclear power, a controlled nuclear reaction with uranium is used as fuel.

Wind Farms: Exploits the kinetic energy of wind for electric power generation by grouping several wind generators.

Photovoltaic Power Plant: It can generate electricity by exploiting the energy from photovoltaic cells that capture sunlight.

Charles Coulomb enunciated what is known as Coulomb's Law to demonstrate experimentally... Continue reading "Understanding Power Generation: Key Concepts and Principles" »

Understanding Electricity Billing

Let's break down the components of your electricity bill:

• Power Term (T. potencia): A fixed amount paid in billing, determined by the contracted power.
• Energy Term (T. energia): The amount paid for the actual energy consumed.

Types of Electricity Rates

• Last Resort Rate (TUR): Replaces the former "integral rate," set by the government. It features a single price for all users. Available for those with contracted power less than 10kW.
• Toll-Free Rate: You can negotiate different conditions than the TUR with a marketer.
• Access Fee: Covers the cost of using the distribution network to bring electricity to your home. Not applicable if you have the TUR.
• Social Bond: A tariff designed to protect households with fewer resources.