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

LDR (Light Dependent Resistor): These are resistors whose resistance value changes when illuminated by light (visible or invisible, such as ultraviolet or infrared).

LDR Features:

1. Its resistance value depends on the amount of light that strikes it.
2. Ohm's Law does not apply directly.
3. Typically made from cadmium sulfide. This material, when kept in the dark, has very few free electrons, resulting in high resistance. However, when illuminated, it releases electrons, decreasing the resistance. This makes it a photoconductor.
4. Manufacturers provide values such as resistance in total darkness (R), resistance under illumination (e.g., 1000 lux), permissible maximum stress, and maximum power.
5. Can be used in lighting systems as detectors.

NTC (Negative Temperature

Dynamics of Suspension

Balance, Center of Gravity, and Roll Axis

The roll center is an imaginary point on an axle where lateral forces are transmitted to the wheels. The imaginary line connecting the front and rear roll centers is called the roll axis. The center of gravity is an imaginary point where the vehicle's entire mass is concentrated.

Charge Transfer and Axes of Rotation

A vehicle pivots around three axes of rotation:

• Longitudinal Axis (Roll): Rotation that occurs when cornering.
• Transverse Axis (Pitch): Rotation that occurs during acceleration or braking.
• Vertical Axis (Yaw): Rotation when the vehicle is subjected to various turning loads.

Sprung and Unsprung Mass

• Sprung Mass: The part of the vehicle that is supported by the suspension system

Gas Installation Principles

An installation consists of containers (portable or stationary), pipe networks, connections, and control and safety devices. These components are essential for safely delivering gas from containers to consumption appliances.

Natural Gas Defined

Natural gas is a chemical compound that may contain impurities. These impurities, which can have value for purposes other than fuel, are typically removed before the gas is piped to consumers. Natural gas is also known as dry or sweet gas. It is obtained from underground deposits of gas, oil, or gas condensate, and can be found either alone or associated with petroleum. The typical working pressure for domestic appliances is 28 gr/cm².

Manufactured Gas

Manufactured gas is primarily... Continue reading "Safe Gas Installation Practices and Types" »

Why Are Hyper-Square Engine Cylinders Efficient?

Hyper-square engines feature a reduced K-factor, meaning the stroke is shorter than the piston diameter. This design allows for a lower average piston speed at the same rotational speed (RPM). Consequently, this enables higher RPM limits, increased power output, and more space for larger valves, which significantly improves volumetric efficiency.

Are Opposed-Piston Engines 2-Stroke or 4-Stroke?

They are typically 2-stroke engines.

Wankel Engine Cycles per Revolution

The Wankel engine operates on a 4-stroke cycle. The rotor completes one full cycle for every three rotations of the output shaft, governed by a 1:3 gear ratio.

Engine Cylinder Dispositions

Common engine layouts include:

• Inline engines
• V engines
• Boxer

Railway Track Crossings: Name, Schema Usage, and Design

Crossings are essential devices that ensure the continuity of connections via different paths and can provide maximum security. They consist of combinations of two devices:

• Bypass: Allows the separation of a railroad into two or more tracks.
• Journey: Allows the intersection of two roads.

Components of Diversions and Crossings

Diversions and crossings are formed from three elements:

• Change: The contra-needle assembly. The needle is the mobile part, and the immobile part is the contra-needle. The end of the needle tip, which is not machined, connects to the union rails and is called the heel. The contra-needle is a normal lane. The needle has to transition from one lane to become normal to an

Common PC Power Problems

Some of the most common power problems and their descriptions:

• High Voltage Fluctuations: Unexpected spikes in voltage.
• Power Outages: A total loss of electrical power.
• Overvoltage: An increase in voltage beyond the normal level. This can occur when a high-energy device is suddenly switched off.
• Voltage Drop: The opposite of overvoltage; a gradual decrease in voltage, potentially leading to a power outage.

Symptoms of Power Supply Issues

Some symptoms that may indicate a power supply problem include:

• Unexpected Freezing: The PC freezes for no apparent reason.
• Data Errors: Write errors or errors accessing files occur.
• Component Failures: Internal components fail, their intensity varies, or the PC behaves strangely when connecting

1. Purpose and Scope

The purpose of this instruction is to determine the specific requirements for electric fences used for livestock, including their power supply and installation. An electric livestock fence is defined as a barrier for animals comprising one or more conductors, such as wires, bars, or barbed wire. The fence energizer is the apparatus that supplies regular voltage pulses to the connected fence.

2. Power Supply

The electric fence energizer can be powered by one of the following methods:

• Connection to an electricity distribution network.
• Connection to batteries or accumulators charged via an electricity distribution network.
• Connection to autonomous batteries or accumulators not intended for connection to a distribution network.

3.

CH-liquids are reused, it is necessary to eliminate the liquid-particle d is easy to perform slow movements nose CN .- reused but the air is expelled, is q necesrio remove particles from the air-horn 30.000N d exertion (because of compressibility) circuit elements: ACTIVE OR GE. (neu) compressor, air pressure communicates and moves a certain caudal.Hay two types: - volume: v reduced to increase py are altered, - dynamic: x pipe passes more and more narrow speed increases, the refrigeration compressors are .. (hid) pump communicates with fluid movement creates vacuum at the inlet and communicates energy to the fluid q ace will move in the circuit .. ACCUMULATORS (neu) to q q flow rate fluctuations will not affect the circuit, to disconnect the... Continue reading "Pneumatic and Hydraulic Systems: Components and Functions" »

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... Continue reading "Fundamentals of Electricity and Circuit Principles" »

Water Distribution Network Fundamentals

The Water Distribution Network aims to supply drinking water service to various intended points for development and building construction. A key difference exists between the installation of the irrigation network and the domestic consumption network.

Consumption Factors and Pressure

Another consumption factor to consider is the pressure required to move the water. This pressure, which is supplied by pumps or mechanisms like height differences between the reservoir and the distribution point, is crucial (the irrigation network operates separately from the main water distribution network).

It is important to know the size of the building. Other essential features of the facility include flexibility (achieved... Continue reading "Water Distribution Network Design and Hydraulics" »