Mechanical Systems, Electrical Quantities, and Electronic Components

Posted on Nov 25, 2024 in Technology

Types of Levers

First Grade

R, PA, F

Second Grade

PA, R, F

Third Grade

PA, F, R

Mechanical Transmission Systems

Worm Gear

Transmits rotary motion between two shafts that form a 90-degree angle (always input and output gear).

Description

  • Has a single tooth-shaped wire thread.
  • The gear is a toothed wheel. Each turn moves a single cog.

Features

  • Transmission of motion through right angles.
  • High cost.
  • Silent operation.

Pinion-Rack System

This system uses a straight-toothed pinion and a rack. When the pinion turns, the rack moves linearly, and vice versa. This mechanism allows for the transformation between rotational and linear motion.

Screw-Nut System

Consists of a screw and a nut with matching inner diameter. If the screw rotates while the nut is fixed, the nut moves linearly along the threaded shaft, and vice versa.

Crank-Rod Mechanism

Consists of a handle and a rod. By turning the wheel, the crank transmits circular motion to the rod, which experiences a back-and-forth motion (also works in reverse).

Crankshaft

A series of rods connected to a single angled shaft, where each elbow serves as a crank. Transforms the rotational motion of a shaft into the reciprocating motion of the rods. It can also convert the swaying motion of rods into the rotational motion of a shaft.

Cam

A wheel with a projection that pushes a follower. The cam converts the rotational motion of the wheel into the linear reciprocating motion of the follower, which follows the cam’s profile.

Eccentric

A wheel whose rotational axis does not coincide with the center of the circle. Transforms the rotational motion of the wheel into the linear reciprocating motion of a rod. Eccentricity is the distance between the center of the circle and the axis of rotation.

Electrical Quantities

  • Quantity of Electricity: Coulomb (C)
  • Current Intensity: Ampere (A), measured with an ammeter; 1A = 1C/second
  • Resistance: Ohm (Ω), measured with an ohmmeter
  • Voltage: Volt (V)

Ohm’s Law

I = V / R, V = I * R, R = V / I

Electrical Power

P = V * I (watts), P = (I * R) * I = I2 * R

Electrical Energy

E = V * I * t (watt-hours, Wh)

Types of Current

Direct Current (DC)

  • Low voltage, low intensity
  • Thin wire
  • Electrons flow in one direction
  • Constant intensity over time

Alternating Current (AC)

  • High voltage
  • Current flows in both directions
  • Intensity is not constant over time, changes continuously

Electronic Components

Tolerance is the difference between the real and nominal resistance value. It can be defined as the range between the maximum and minimum values of a resistor.

Potentiometers

Variable resistors whose resistance can be changed using a cursor. Used to adjust volume, brightness, etc.

LDR (Light-Dependent Resistor)

Resistance varies with the amount of light received (+ light, – resistance).

Thermistor

  • NTC (Negative Temperature Coefficient): + temperature, – resistance
  • PTC (Positive Temperature Coefficient): + temperature, + resistance

Diode

An electronic component made of semiconductor material that allows current flow in only one direction.

LED (Light-Emitting Diode)

A diode that emits light when current passes through it.

Limit Switches

Buttons operated by a lever pushed by a moving object. Can be Normally Open (NO) or Normally Closed (NC).

Switches

Direct current through one path or another.

Capacitor

A component capable of storing electric charge, consisting of two flat parallel metal plates separated by an insulator. When connected to a voltage source, the plates accumulate equal but opposite charges. When disconnected, the capacitor acts as a generator.

Transistor

An important electronic component with three layers of semiconductor material, forming three terminals: collector (C), base (B), and emitter (E).

Types

  • PNP: Collector (P), Base (N), Emitter (P)
  • NPN: Collector (N), Base (P), Emitter (N)

Databases

  • Elements:
    • Record (row): Contains all information on various aspects of the same person or subject.
    • Field (column): Different categories into which the contents of a record are divided.
  • Database: The collection of data collected and stored according to specific criteria.
  • Table: The basic foundation object. A database can have multiple tables, each considered the most elementary unit.
  • Form: Contains the same data as a table, but in a more distributed, orderly, and easy-to-use way. Allows for changing or entering information.
  • Consultation (Query): The most powerful process for interrogating the database. Used to organize and make frequently used data available.
  • Report: A summary containing one or more tables. Reports are often presented on paper to organize stored data.