Notes, summaries, assignments, exams, and exercises for Technology for Secondary education

The Atom

The atom is the fundamental unit of matter, consisting of a nucleus containing protons and neutrons, surrounded by orbiting electrons.

Atomic Structure

Atoms are composed of negatively charged electrons, positively charged protons, and neutrons, which carry no charge.

Electrical Charge

Electrical charge is a property of matter responsible for electrical phenomena. Bodies with the same charge repel each other, while those with opposite charges attract.

Static Electricity

Static electricity occurs when electric charges remain at rest and do not move along a material.

Electric Current

Electric current is defined as the continuous movement of electrons.

Conductors and Insulators

• Conductive Materials: Substances that allow the passage of electric

Electric Circuits: Core Concepts

An electric circuit is a closed path that allows electrons to circulate, enabling the electric current to perform useful work.

Key Definitions

• Conductors: Materials like copper, aluminum, and iron that allow electricity to flow.
• Insulators: Materials like wood, ceramics, and plastic that prevent the flow of electricity.

Circuit Components

• Generators: Supply electric current to the circuit.
• Conductors: Allow the flow of electric current.
• Receptors: Transform electrical energy into useful work.
• Control Elements: Govern the operation of the circuit.

Circuit States

• Open Circuit: The path is broken; current cannot flow.
• Closed Circuit: The path is complete; current flows, allowing components like bulbs or motors to operate.

Electrons...

Plastic Extrusion and Molding Processes

Extrusion profiles are used to create long, uniform sections. This process utilizes a specialized machine called an extruder, which operates similarly to a kitchen cutting machine. Plastic granules are poured into a feed hopper and flow into a chamber where a screw rotates. The extruder heats the plastic to between 150 and 250 degrees Celsius to soften it and force it through a die, creating the desired shape.

Extrusion and Blow Molding

Extrusion and blow molding are used for creating items like electrical lighting components, bottles, and toys. A hollow preform, called a parison, is extruded and then placed into a mold. Air pressure is then injected to expand the plastic, conforming it to the mold's shape....

Fundamental Electronic Components and Measurement

Resistors: Function and Characteristics

Resistors are components that offer opposition to the passage or circulation of electric current, causing a potential voltage drop across their terminals. Key characteristics include:

• Ohmic resistance magnitude and tolerance (limiting deviations established by the manufacturer).
• Power rating (the maximum power the resistor can safely dissipate).

Resistors must operate under stable conditions.

Types of Resistors

Fixed Resistors

These components maintain a constant ohmic value and typically have two terminals. Their resistance value is often obtained by modifying carbon layers using a spiral cut that forces the electric current to follow a specific, calculated path....

Basic Electrical Concepts

Voltage (Tension)

Voltage (also known as Tension or electromotive force) is the energy with which a generator is able to push electrons through a circuit.

Electric Current (Intensity)

Electric Current (or Intensity) is the number of electrical charges flowing through a circuit per unit time. It is measured in amperes (A).

Resistance

Resistance is the opposition a material offers to the flow of electric current. Materials with high resistance make it difficult for electricity to pass through. Resistance is measured in ohms (Ω).

Electric Power

Electric Power indicates the rate at which a device performs its function. The power consumed by a receiver is directly related to the voltage and current that feed the circuit. Power...

Metalworking Processes and Techniques

Casting Process

Casting consists of introducing molten metal into a container with an internal cavity called a mold. Molds can be manufactured from steel or foundry sand.

1. The metal is heated in an oven until it melts.
2. The liquid metal is poured inside the mold.
3. It is cooled until the metal solidifies.
4. The solidified part is removed from the mold.

Material Handling

These techniques are carried out with tools and machine tools using prefabricated materials such as bars, rods, plates, etc.

Marking Tools

• Punch
• Scriber
• Dividers

Cutting Techniques and Tools

• Sheet metal shears or snips
• Guillotine
• Press and die cut
• Hacksaw

Circular Saw

A machine tool mainly used for cutting large boards or plates. It can make straight and oblique...

5.3-THE STRENGTH OF A CYLINDER: the pressure is the relation between force and the area in which it operates.
The unit is the pascal, which is 1 N/1m2, this unit is very small and usually is used kp/cm2, referring to the kiligramo strength kg/cm2.
The force of the rod of a cylinder is: F = p * A = p * 3.14 * R2.
We will get stronger the higher the pressure and radius of the plunger.
In the double eject cylinder fails.
In the return stroke of cilindors double effect: F = p * p * A = 3.14 (R2-r2).
6-ELEMENTS OF CONTROL: The valves are divided into: operated valves and regulation.
6.1-operated valves: regulating the incoming air directly into the cameras and, depending on the type of cylinder used one or another.
a) nuemro holes, called...

What is Computer Security?

Security is the set of actions, tools, and devices whose purpose is to provide a computer system with integrity, confidentiality, and availability.

• Integrity: Prevents the modification of information by any user who has not been previously authorized.
• Confidentiality: Prevents data visualization by users who have no privileges on the system.
• Availability: Ensures that authorized users have access to the system and its resources when needed.

What Must We Protect Against?

We must protect against ourselves, accidents, breakdowns, malicious intruders, and malware.

Active Security

Active security is designed to prevent damage to computer systems:

1. Appropriate passwords
2. Data encryption
3. Computer security software

Passive Security

Passive

Simple Machines

Simple machines are basic devices formed by a single element. Their primary function is to multiply human force. Ancient philosophers identified five key simple machines: the lever, the wheel and axle, the inclined plane, the screw, and the wedge.

Types of Machines

• Drive Machines: These machines focus solely on producing motion.
• Operational Machines: These machines perform specific tasks, such as a vacuum cleaner.

Elements of a Machine

• Mechanisms: Moving parts that transmit motion to other machine components.
• Structure: Supports the mechanisms.
• Engine/Motor: Generates motion or force.

Force

Force is anything that can change the motion of a body or cause deformation. It is measured in Newtons (N). Approximately 0.1 N is the force exerted...

Understanding Structural Elements and Forces

A structure is a set of elements capable of withstanding forces and transmitting them to the point where it rests, ensuring durability and stability. These forces are commonly known as loads.

Key Structural Forces

• Stress: The internal force that appears within elements when a structure is subjected to loads or other external forces.
• Tension: An internal force consisting of two forces that tend to increase an element's length (stretch it).
• Compression: An internal force that tends to decrease an element's length (compress it).
• Flexion (Bending): Forces that tend to bend an element.
• Shear (Cutting): Forces that act parallel to an element's cross-section, tending to cut it or displace one section relative