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

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... Continue reading "Simple Machines and Mechanisms" »

Why Must an Ohmmeter be Calibrated When Changing Ranges?

What is Calibration?

An ohmmeter must be calibrated each time you change the measuring range to verify the proper operation of the instrument. When calibration is not performed, the needle may deflect incorrectly on the ohmmeter scale. Calibration involves measuring a known resistance standard and comparing it with the ohmmeter reading. This should be done at several points on the instrument's scale and for various scales.

Connecting an Ammeter to Measure Current Through a Resistor

Series vs. Parallel Connection

In which of the two forms mentioned would you connect an ammeter to measure the intensity of current flowing through resistor R? Justify your answer.

The correct way to connect an ammeter... Continue reading "Ohmmeter Calibration and Circuit Analysis Techniques" »

Closed-Loop Control System Components

Process

A continuous operation involving a series of systematic actions or changes designed to achieve a particular result. Common types include transformation, transport, and accumulation processes.

Primary Element of Measurement (Sensor)

An instrument that senses the variable to be measured. This variable can be physical or analytical, and sensors can be either intrusive or non-intrusive.

Transmission Elements

Devices that normalize and condition the sensor signal into a standard digital or analog signal, such as 4-20 mA electrical current, 1-5 VDC electrical voltage, or 3-15 psi (0.2-1 bar) pneumatic signals.

Indicator or Recorder

A device that provides a historical record of process variables over time, allowing... Continue reading "Closed-Loop Control Systems: Core Concepts & Components" »

When you need to make a motion transmission, you usually work directly with axes: We support a fixed, usually cylindrical axis, which serves as another element, such as a wheel or a pulley, to turn around. Tree: It's a bar, usually cylindrical, that transmits circular motion. Coupling: The element that allows joining two trees or two axes. Wheel Bearings: These are two completely smooth rim wheels that are in direct contact with one another for moving forward. Gearboxes: We have a minimum of two formed mechanisms, sprockets, constructed in such a way that matches the outgoing motion and transmits circular motion and power. Types of Gears: Cylindrical straight, helical, and bevel. A series of small items would not be possible without the proper... Continue reading "Understanding Motion Transmission Mechanisms in Machinery" »

Palmer Micrometer: Precision Measurement

A Palmer micrometer is a direct-reading measuring instrument. It provides the length value directly, enabling measurements with a precision of 0.01 mm and, in some models, 0.001 mm.

Micrometer Parts

• Body
• Tube
• Rotating drum
• Friction screw
• Circular graduation
• Linear graduation
• Brake
• Mobile probe
• Fixed and insulating probe handles

Micrometer Management

A micrometer can be used to measure parts on marble, on machines, or as support for serial investigations. The measurement procedure is as follows:

1. Open the tool to a range slightly greater than the dimension to be measured.
2. Position the piece between the probes.
3. Gently rotate the drum until the probes support against the piece. This should be done by acting through the

Networking Concepts: Questions and Answers

1. Which OSI Layer Handles Binary Transmission and Physical Aspects?

Answer: The Physical Layer

2. Device for Fiber Optic Fault Monitoring and Performance?

Answer: Optical Time-Domain Reflectometer (OTDR)

3. Key Characteristics of Fiber Optic Cable

• It is not affected by Electromagnetic Interference (EMI) or Radio Frequency Interference (RFI).
• It is generally the most expensive type of LAN cabling.

4. When to Use a Straight-Through Cable?

Answer: When connecting a host to a switch.

5. Cat 5 Cable for Direct Host-to-Host Ethernet Connection?

Answer: Crossover cable.

6. Signal Transmission Method Using Radio Waves?

Answer: Wireless.

7. Common Connector for Twisted Pair Cable in Business LANs?

Answer: RJ-45.

8. Characteristic

Fundamentals of Pneumatic and Hydraulic Control

Pneumatic and hydraulic systems utilize different mediums for control:

• Electric Control: Uses electrical signals.
• Pneumatic Control: Uses air pressure (a gas).
• Hydraulic Control: Uses liquid (typically oil).

Characteristics of Working Fluids

The primary characteristics defining fluid behavior in these systems are pressure and flow.

Note on Fluid Characteristics: Pressure ($P$) and Flow ($Q$) are defined by fundamental physics principles:

• $P = F / S$ (Pressure equals Force divided by Surface Area)
• $Q = V / T = S \times \text{displacement} / T$ (Flow rate equals Volume divided by Time)

Components of a Pneumatic System Installation

A complete pneumatic installation includes:

• Compressor and tank (storage)
• Conditioning

Heavy Work

This term refers to the part of a building's construction that includes the foundation, structural framework, walls, and roof girders.

Joist

A smaller beam, sometimes supported by principal beams or girders. In the context of poplar wood, this name also refers to the first piece carved with an axe from the tip of the trunk, typically 5 feet long.

Cuarton

This term indicates a piece obtained by sawing a whole tree crosswise. Generally, this name is given to sawn pieces with a thickness and width ranging from 2 to 6 inches.

Crowbar / Prop

This term can refer to:

• Vertical uprights or props used to support the formwork for concrete slabs and beams. Shims are often placed at their base to adjust the height.
• A sturdy lever or bar used for prying

Carac. Line Negative Suction

The suction pipe must be designed to ensure smooth pump functioning. It should be straight, tight, and as short as possible to prevent air entry. Avoid sudden widening or narrowing; use eccentric cones with the wider end horizontal. Avoid elbows in planes adjacent to other elbows.

When selecting the proper pipe diameter, consider head losses and maximum speed. Use tables to calculate the most suitable pipes for operating conditions.

Always mount the suction pipe in an upward position towards the pump to prevent air accumulation, which can reduce capacity and cause pump issues. Horizontal sections should have a slope of at least 2% and a sufficient straight length to stabilize liquid flow.

A foot valve should be mounted... Continue reading "Optimizing Pump Suction and Discharge Piping" »

Industrial Processes and Materials

Item 1: Production Cycle and Industry Types

1. The Production Cycle:

Industries can be classified into:

• Extractive Industries
• Processing Industries

2. Extraction of Raw Materials:

According to the type of resource:

• Mineral energetics
• Non-metallic rocks and minerals
• Hydrocarbons
• Plant and animal materials

3. Processing Industries:

• Steel and metal
• Petrochemicals
• Paper and artificial wood industries
• Textiles and leather
• Industrial ceramics, glass, and building materials

4. Automobile Manufacturing Process:

1. Realization of parts by melting and molding.
2. Union of parts by welding, adhesives, or threaded elements.
3. Realization of finishing by coating with paints, enamels, and varnishes.
4. Control, product warehousing, and packaging.

5. Saving