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

Resistors

Types of Resistors

Charged Carbon Resistors

Characteristics:

• Low stability values
• Robust mechanical and electrical properties
• Strong overload support
• Temperature coefficient: C ±100ppm
• High noise
• Tolerances above 5%

Pyrolytic Carbon Film Resistors

Characteristics:

• Very stable resistive element composed of carbon and insulation
• Reduced noise
• Widely used
• Good heat support
• Features similar to carbon composition resistors

Metal Film Resistors

Characteristics:

• Composed of Ni-Cr, Au-Pt
• Tolerance > 0.1%
• Poor heat support
• Good thermal stability
• Very sensitive to frequency and voltage variations
• High price

Potentiometers

Characteristics:

• Ohmic value
• Power dissipation
• Linearity
• Tolerance
• Angle of rotation
• Stability
• Insulation resistance
• Minimum resistance
• Temperature coefficient
• Noise
• Resolution
• Moisture

Hydraulic Systems: Principles and Applications

Introduction: The hydraulic method is chosen for tasks that involve the transmission of large forces. This method is used to create and control forces and movements with pressurized fluid.

Advantages of Hydraulic Systems

• Great Efforts: Ability to transmit substantial forces.
• High Power-to-Weight Ratio: Efficient performance relative to system weight.
• Precision: Accurate positioning of heavy loads.
• Smooth Movement: Regular and smooth operation.
• Accurate Speed Control: Precise control over operational speeds.
• Starting Under Maximum Load: Capability to start under full load conditions.
• Easy Overload Protection: Simple mechanisms to protect against overload.

Oil Hydraulic Fluid Circuit

Oil Hydraulic Fluid Circuit:... Continue reading "Hydraulic Systems: Principles and Applications in Fluid Power" »

Interest-Based Learning in Early Childhood Education

Interest-based learning is a pedagogical method that organizes educational content around a core based on the needs and interests of children. This approach focuses on presenting activities in various situations, motivated by the environment. For example, introducing the concept of fruit through engaging activities.

Organizing Activities for Success

Activities are organized to encourage children to think and pursue success. Choosing an axis of interest that sparks their curiosity is crucial. This method can be implemented with children as young as 18 months old.

Learning Corners: A Key Pedagogical Resource

Learning corners are a valuable pedagogical resource that involves creating organized play... Continue reading "Child-Centered Learning: Activities, Methods, and Play" »

PRACTICE 13: TRANSFORMER SHORT-CIRCUIT TEST MEASUREMENT

Introduction

The short-circuit test involves shorting the secondary winding terminals and applying a reduced primary voltage (Ucc) to allow rated current flow in the primary winding.

Outline

Fundamentals of the Test

This test determines nominal copper losses, as short-circuit iron losses are negligible due to the low applied voltage (Ucc). Iron losses are roughly proportional to the square of the magnetic flux density (B), which is significantly reduced at low voltage. If Ucc = 5% U_1n, then Bcc ≈ 0.05B, where:

• B = maximum flux density at nominal voltage
• Bcc = maximum flux density during the short-circuit test

Therefore, P_FECCAS = (0.05)² ⋅ P_Fe = 1/400 ⋅ P_Fe, where:

• P_Fe = nominal iron losses
• P_FECCAS

Atomic Structure and Electric Charge

The following table summarizes the structure of an atom:

Electric charge is the excess or deficit of electrons in a body. It is measured in Coulombs.

Electric Current

Electric current is the flow of electric charge through a conductor. A conductor material contains many free electrons. Materials that do not have free electrons are insulators. For current to exist, there must be free electrons and a potential difference. Current can be of two types:

• Direct Current (DC): Electrons move in the same direction.
• Alternating Current (AC): Electrons change direction periodically,

Electric Machines: An Overview

Electric machines: any device capable of generating, transforming, or using electric power (generators, alternators, transformers, motors)

Transformers

Transformers: These static machines modify the characteristics of electric current (I and V). They consist of a ferromagnetic core sheet and two windings. The first winding transports high voltage current, and the second circuit is for use. They function through electromagnetic induction, generating an electromotive force (AC).

Motors

Motors: Rotating electrical machines that transform electric energy into mechanical energy. According to the current type, they are:

• DC (Direct Current): Separately excited, series, shunt, compound
• AC (Alternating Current): Speed-synchronous

Verb "To Be" Forms

Am, are, is

Present Simple

Infinitive or add 's' / Use don't for negatives

Past Simple

Add -ed (or second column for irregular verbs) / S + didn't + infinitive / Did + subject + infinitive

Used for actions at a specific time, consecutive actions in the past, a short action interrupting a longer one, or describing past states.

Past Tense of "To Be"

Was/were

Passive Voice

Subject + to be + past participle (-ed or third column) + by + agent

• Present Simple: am/are/is + past participle
• Past Simple: was/were + past participle
• Present Continuous: am/are/is being + past participle
• Past Continuous: was/were being + past participle
• Present Perfect: have/has + been + past participle
• Modal: modal + be + past participle
• Future Simple: will be + past participle

Question

Detailed engineering is the phase in which information is taken from the basic engineering and developed to a sufficient degree to allow the construction of the project. The goal is to develop detailed information and documentation.

Activities

• Define the different areas that will form the subject of the project installation.
• Define the means of production, creating a list of machines, equipment control, and automation equipment involved in the system.
• Definition of networks and supporting facilities.
• Organization for the means of production, defining for each workstation which machines and items are controlled and monitored.
• Organization of production cycles so that there is an adequate flow between each machine and workstation, minimizing downtime.

Multi-Circuit: Intermittent Power Supply

This electronic circuit provides intermittent power and can be supplemented with a device that detects malfunctions by placing two additional transistors.

Veri.Mani: Pilot Testing and Reverse Voltage

Pilot testing began with a system that does not function in reverse voltage to current.

Fuel Level Sensors: Analog and Digital Indicators

Fuel level sensors are responsible for displaying the amount of liquid in a deposit. These can be analog or digital and are based on the principle of a float or rheostat.

Oil Pressure Monitoring: Lamp and Monocontacto

Oil pressure is usually controlled by a lamp. If the oil level is low, the unit responsible for lighting the lamp is called a monocontacto. When cranking or starting... Continue reading "Automotive Electronic Systems: Functionality and Operation" »