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

Understanding Programmable Logic Controllers (PLCs)

A Programmable Logic Controller (PLC) is an electronic device capable of processing analog variables, digital, numeric, and alphanumeric information. PLCs are designed for real-time monitoring and control of automated industrial processes.

External circuits consist of sensors, which send information from the industrial process to the automaton, and actuators, responsible for executing the program's commands.

PLC Memory

The primary function of PLC memory is to store program instructions, data, internal states, and input/output states. PLC memory is typically organized into distinct work areas.

Memory Types

• RAM (Random Access Memory): Read-write memory. In the absence of power, information volatilizes

Asynchronous Machine Analysis: Torque, Fields, and Braking

Starting Torque and Stator Connection

Q: Demonstrate the relationship between the starting torque of an asynchronous machine with the stator connected in a triangle, being three times higher than the same machine with the star-connected stator.

Ta star = (1 / √3)² Tb

Ta = 1 / 3 Ta

Ia star = 1 / 3 Ta

The starting current in star is 1/3 in a triangle, reducing starting torque to 1/3.

Magnetic Field and Rotor Speed

Q: Demonstrate that the magnetic field produced by the stator currents of an induction machine turns at the same speed as the magnetic field produced by currents induced in the engine.

The connection speed of the stator field created by the rotor is the sum of the speed but the torn... Continue reading "Asynchronous Machine Torque, Magnetic Fields, and Braking Analysis" »

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

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" »

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.

Electrical Protection Devices and Stepper Motors Explained

Thermal Switches

These are automatic switches that react to overcurrent slightly higher than the rated value, ensuring disconnection in a short circuit. To ensure sufficient lead time for disconnection, they take advantage of the deformation of a bimetallic strip, which curves as a function of the heat produced by the current passing through it.

Magnetic Switches

These are switches that react to high overcurrents, operating in a short enough time so as not to harm the network or associated devices. To initiate disconnection, they utilize the movement of an iron core in a magnetic field proportional to the value of the circulating current.

Magneto-Thermal Switches

A circuit breaker is a device... Continue reading "Circuit Breakers and Stepper Motors: Functionality & Types" »

1. Communication Circuit Questions

What is K in the communication circuit?

K represents the generation of a message by the issuer and its transmission.

What types of waves are the signs usually?

Signs are typically acoustic or electromagnetic waves.

What is the channel?

The channel is the physical medium that supports information transmission.

What does K stand for in wired or wireless communication?

• Wired: Electromagnetic waves (like sound) are transmitted through a wired medium.
• Wireless: Electromagnetic waves are transmitted, but not sound.

Wired media utilize cables, such as conventional metal wires.

2. Wave Definitions

Wavelength

The distance a wave travels during one complete oscillation.

Period

The time between two consecutive wave peaks.

Frequency

The... Continue reading "Understanding Communication Circuits and Wave Transmission" »

1. What is the First Thing to Set to Make a Draft CATV?

Bring the correct response: The bandwidth to use.

2. For Purposes of Receiving Local Channels Broadcast by Cable Signal, Which is More Advisable?

Response: Receiving each local channel individually with a Yagi antenna.

3. What is the Most Important Recommendation for the Location of Satellite Dishes?

Bring the correct response: The distance should be as short as possible to the equipment or satellite receivers.

4. What Defines Television Programming for a Cable Company?

Bring the correct response: It is purely a business decision.

5. Which of the Following is Not Covered in the 10-Step CATV Design Process?

Response: NA

6. Definition of Final Quality Objectives

Quality objectives for the subscriber... Continue reading "CATV System Design and Signal Propagation" »