Comprehensive Term 1 Study Guide for Grade 8 Subjects

Electronic Tools and Components

Electronic tools are instruments used to assemble, repair, maintain, and test electronic circuits and devices. They allow technicians to work safely, accurately, and efficiently.

Basic Hand Tools and Their Categories

1. Driving Tools

Purpose: Used to tighten or loosen screws, nuts, and bolts during assembly or repair.

  • Flat-head Screwdriver: A screwdriver with a straight, flat blade designed to fit screws with a single straight slot across their heads. It is used to install, tighten, remove, or adjust screws in electronic devices, appliances, furniture, and electrical equipment.

  • Phillips Screwdriver: Features a cross-shaped tip that fits Phillips screws, providing better grip and reducing the chance of the tool slipping.

  • Slotted Screwdriver: Another name for the flat-head screwdriver, used specifically on slotted screws.

  • Jeweler's Screwdriver Set: A set of very small screwdrivers for delicate electronics like watches, phones, and glasses.

  • Stubby Screwdriver: A short screwdriver used in tight spaces where standard-length tools cannot fit.

  • Torx Screwdriver: Features a six-point star-shaped tip designed for Torx screws, commonly found in laptops, game consoles, and automotive equipment.

  • Allen (Hex) Wrench: An L-shaped tool with a six-sided hexagonal tip used for hex socket screws found in furniture and industrial machinery.

  • Nut Driver: A tool with a socket-shaped tip used specifically to tighten or loosen hex nuts.

2. Soldering Tools

Purpose: Used to permanently join electronic components using molten solder to create electrical and mechanical connections.

  • Soldering Iron: A handheld electrical tool with a heated metal tip that melts solder to join wires, components, circuit boards, and terminals.

  • Soldering Station: An iron with adjustable temperature control. It often includes a heat-resistant stand to safely support the hot iron and protect the workbench from damage.

  • Solder Wire: A metal alloy used to create the actual electrical connection between parts.

  • Desoldering Pump (Solder Sucker): A manually operated vacuum tool that removes molten solder from components and terminals without damaging surrounding parts.

  • Desoldering Wick: A braided copper strip that absorbs melted solder, used for cleaning circuit boards.

3. Splicing Tools

Purpose: Used to prepare, connect, and repair electrical wires.

  • Wire Stripper: Designed to remove insulation or protective coating from electrical wires without damaging the metal conductor inside.

  • Crimping Tool: Compresses wire terminals onto cables to install connectors securely.

  • Combination Pliers: Multi-purpose tool used for gripping, bending, and cutting wires.

  • Side Cutter (Diagonal Cutting Pliers): Hand tool with sharp, angled jaws designed for trimming excess wire, cutting leads, or removing damaged wire ends.

  • Long-Nose Pliers (Needle-Nose): Pliers with long, pointed jaws for gripping and positioning components in hard-to-reach areas.

4. Boring Tools

Purpose: Used to create holes in materials like plastic, metal, or PCBs.

  • 12V12V Mini Drill: A compact, rechargeable cordless power tool used for precision drilling on printed circuit boards, wood, and lightweight plastics.

  • Portable Electric Drill: A handheld tool used for heavy-duty drilling in wood, metal, concrete, or driving screws efficiently.

  • Metal Files: Hardened steel tools with sharp cutting teeth used to smooth rough edges, remove burrs, or enlarge holes after drilling.

  • Pin Vise: A small, hand-operated drill for precision work on circuit boards.

  • Drill Bits: Replaceable cutting tools used with drills to create holes of various sizes.

5. Cutting Tools

Purpose: Used to cut wires, cables, and various electronic materials.

  • Utility Knife: Features a retractable blade for making straight cuts on insulation, tape, cardboard, and plastic.

  • Hacksaw: A hand-operated tool with a fine-toothed replaceable blade for cutting metal rods, pipes, and hard plastics like PVC.

  • Cable Cutter: A heavy-duty tool specifically for cutting thick electrical cables.

6. Auxiliary Tools

Purpose: Support miscellaneous tasks like inspection, holding, and protection.

  • Tweezers: Small gripping tools for holding tiny electronic components.

  • Magnifying Glass: Optical tool with a convex lens to inspect tiny details, solder joints, and detect defects in circuit boards.

  • Digital Multimeter: Instrument used to measure voltage, current, and resistance to test electrical circuits.

  • Helping Hands: A stand equipped with clips to hold workpieces steady during soldering.

  • Anti-static Wrist Strap: A wearable safety device that grounds the user to prevent electrostatic discharge (ESD) from damaging sensitive components.

  • Paint Brush: Used to gently remove dust, debris, or solder residue from PCBs and keyboards.

Sensors

A sensor is an electronic device that detects physical changes (temperature, light, motion, pressure, etc.) and converts them into electrical signals.

Types of Sensors

  • Analog Sensor: Produces a continuous electrical signal proportional to the physical quantity being measured.

  • Digital Sensor: Produces discrete signals (HIGH/1 or LOW/0), suitable for microcontrollers.

Common Kinds of Sensors

  • Temperature Sensor: Measures the temperature of an object or environment; used in HVAC systems and medical devices.

  • Light Sensor (LDR): A Light Dependent Resistor whose resistance decreases as light intensity increases; used in street lights.

  • Ultrasonic Sensor: Uses high-frequency sound waves to measure distance by timing the return of an echo; used in parking assistance.

  • Infrared (IR) Sensor: Detects infrared radiation to determine presence or movement; used in remote controls.

  • PIR Motion Sensor: Detects heat naturally emitted by people/animals; used in burglar alarms.

  • Humidity Sensor: Measures water vapor in the air for weather stations and environmental monitoring.

  • Pressure Sensor: Measures forces exerted by gases or liquids; used in automotive and medical instruments.

  • Gas/Smoke/Flame Sensors: Detect presence of dangerous gases, smoke particles, or UV/IR light from flames for fire safety.

  • Sound Sensor: Converts sound waves to electrical signals; used in voice-activated devices.

  • Touch Sensor: Detects physical contact; used in smartphones and touch lamps.

  • Water Level / Soil Moisture Sensors: Measure water height in tanks or water content in soil for automation.

  • Hall Effect Sensor: Detects magnetic fields without physical contact; used in brushless DC motors and speedometers.

  • Tilt/Vibration Sensors: Detect orientation changes relative to gravity or mechanical shocks.

Motors

Motors are electromechanical devices that convert energy into mechanical motion (rotational or linear).

Types of Motors

  • AC Motor: Operates on alternating current; high efficiency for industrial and household appliances.

  • DC Motor: Operates on direct current; common in robotics, toys, and portable devices.

Common Kinds of Motors

  • Servo Motor: Precision motor with a feedback control system for accurate angle, position, and speed; used in robotic arms.

  • Stepper Motor: Rotates in small, precise "steps" rather than continuous rotation; used in 3D3D printers and CNC machines.

  • Brushless DC (BLDC) Motor: Operates without carbon brushes, leading to higher efficiency and longer life; used in drones.

  • Brushed DC Motor: Uses carbon brushes and a commutator; inexpensive and simple; used in small appliances.

  • Geared Motor: Combination of a motor and a gearbox to increase torque and reduce speed for heavy loads.

  • Universal Motor: Can run on AC or DC and produces high speeds; used in vacuum cleaners and drills.

  • Induction Motor: An AC motor operating by electromagnetic induction; highly reliable for water pumps.

  • Synchronous Motor: Rotor rotates at the exact speed of the magnetic field; used in precision timing and clocks.

Scientific Research: Nature, Ethics, and Safety

Nature of Research

  • Systematic: Follows a step-by-step process from problem identification to conclusion.

  • Empirical: Based on direct observation and measurable evidence, not opinions.

  • Logical: Uses reasoning and critical thinking to produce valid conclusions.

  • Objective: Remains unbiased and based on facts.

  • Replicable: Can be repeated by others using the same methods to verify reliability.

  • Controlled: Variables are managed to improve accuracy.

  • Valid/Reliable: Measures what it intends to and produces consistent results under similar conditions.

Types of Scientific Research

  • Basic Research (Pure Research): Curiosity-driven research to increase scientific knowledge and explain natural phenomena (e.g., how bacteria reproduce). No immediate practical application.

  • Applied Research: Uses knowledge to solve real-world problems and improve technologies (e.g., developing water filtration systems).

Ethics and Institutional Research Forms (ISEF)

  • Form 1A (Student Checklist): Lists project requirements and organizes the process.

  • Form 1B (Approval Form): Grants permission before conducting research.

  • Form 3 (Risk Assessment): Identifies hazards to protect researchers and the environment.

  • Form 4 (Human Participants): Requires Informed Consent, privacy, and voluntary participation.

  • Form 5A & 5B (Vertebrate Animals): Ensures humane treatment and scientific justification.

  • Form 6A (PHBA): For hazardous biological agents like bacteria or viruses.

  • Form 6B: For usage of human or vertebrate animal tissue/body fluids.

Biosafety Levels (BSL)

  • BSL-1: Low risk; non-pathogenic bacteria; basic lab practices.

  • BSL-2: Moderate risk; blood samples; additional protective equipment.

  • BSL-3: High risk; tuberculosis; specialized ventilation and controlled access.

  • BSL-4: Extreme risk; Ebola virus; maximum containment and highest protection levels.

Intellectual Property (IP)

  • Copyright: Protects creative works like books, music, and research papers.

  • Patent: Protects new inventions, machines, and processes.

  • Trademark: Protects brand names, logos, and symbols.

  • Trade Secret: Protects confidential business info like recipes.

Araling Panlipunan: Katangiang Pisikal ng Daigdig

Theories of Earth's Origin

  • Big Bang Theory: Universe began with a massive explosion approximately 13.813.8 billion years ago.

  • Nebular Theory: Proposed by Kant and Laplace; Solar system formed from a rotating cloud of gas/dust.

  • Continental Drift Theory: Proposed by Alfred Wegener (19121912); continents were once a supercontinent called Pangaea.

  • Plate Tectonic Theory: Lithosphere is divided into plates whose movement causes earthquakes and volcanoes.

  • Seafloor Spreading Theory: Proposed by Harry Hess; magma creates new seafloor, pushing continents apart.

Themes of Geography

  1. Lokasyon: Absolute (using latitude/longitude) and Relative (neighboring places).

  2. Lugar: Physical (climate, rivers) and Human (language, religion) characteristics.

  3. Interaksiyon ng Tao at Kapaligiran: How humans adapt to and modify nature.

  4. Paggalaw: Migration of people, goods, and ideas.

  5. Rehiyon: Areas with similar climate, culture, or language.

Ancient Civilizations

Mesopotamia (Cradle of Civilization)

  • Location: Between Tigris and Euphrates rivers (modern Iraq).

  • Contributions: Cuneiform writing, Ziggurats, the Wheel, Code of Hammurabi.

Egypt

  • Location: Nile River.

  • Contributions: Hieroglyphics, Papyrus, Pyramids, Mummification, 365365-day calendar.

Indus

  • Location: Indus River.

  • Contributions: Sewerage systems, grid pattern urban planning, standard weights.

China

  • Location: Huang Ho and Yangtze rivers.

  • Contributions: Silk, Paper, Compass, Gunpowder, Printing, Confucianism.

Minoan vs. Mycenaean

  • Minoan: Developed on Crete (3000−14503000-1450 BK); peaceful, sea traders, used Linear A writing, famous for Knossos palace.

  • Mycenaean: Developed on mainland Greece (1600−11001600-1100 BK); militaristic, built Cyclopean walls, used Linear B (early Greek), involved in the Trojan War.

Values Education: Emotions and Resilience

Understanding Emotions

Emotions consist of three parts:

  1. Subjective Experience: Personal feelings toward a situation.

  2. Physiological Response: Physical changes like rapid heartbeat or sweating.

  3. Behavioral Response: Expressed behavior like crying or smiling.

  • Prudence (Maingat na Paghuhusga): The ability to think deeply before acting, considering consequences.

  • React vs. Respond: Reacting is impulsive; Responding is thoughtful and responsible.

Family and Resilience

  • Resilience: The ability to "bounce back" (Latin: resilire) from trials.

  • Family Types:

    • Nuclear: Parents and children.

    • Extended: Includes relatives like grandparents and cousins.

    • Single-Parent: One parent Raising children.

    • Grandparent Family: Grandparents as primary caregivers.

MAPEH: Arts and Sexuality

Performing and Visual Arts

  • Cosplay (Costume + Play): Coined by Nobuyuki Takahashi in 19841984. Dressing as characters from media.

  • Pop Genres: K-pop (South Korea), J-pop (Japan), C-pop (China/Taiwan/Hong Kong).

  • Street Art: Public visual art (Graffiti, Stencil Art, Murals).

Sexuality and Gender

  • SOGIE: Sexual Orientation, Gender Identity, and Gender Expression.

  • Sex: Biological attributes (chromosomes, hormones) classified as male or female.

  • Gender: Socially constructed roles and behaviors (masculine, feminine).

  • LGBTQIA+: Inclusive term for diverse orientations and identities.

Filipino: Panitikan sa Panahon ng Propaganda

Historical Context (1872−18961872-1896)

  • GOMBURZA Execution (18721872): Awakened Filipino nationalism.

  • La Solidaridad (18891889): Newspaper of the Propaganda Movement.

  • Kataas-taasan, Kagalang-galangang Katipunan (K.K.K.): Founded by Andres Bonifacio in 18921892 for armed revolution.

Notable Works

  • "Sa Kabataang Pilipino" (Jose Rizal): Encourages youth as the hope of the fatherland.

  • "Kartilya ng Katipunan" (Emilio Jacinto): Ethics guide for Katipuneros (1414 lessons on honor, equality, and charity).

English: Afro-Asian Literature (Prose)

Elements of Plot

  1. Exposition: Characters and setting intro.

  2. Rising Action: Conflict starts.

  3. Climax: Turning point.

  4. Falling Action: Resolution begins.

  5. Resolution: Ending.

Major Stories

  • "The Mouse Maid" (India): A mouse turned girl searches for a husband, eventually proving a mouse is stronger than the sun, cloud, wind, or mountain. Theme: True nature.

  • "The Lion Makers" (India): Four friends; three are scholars who revive a lion using knowledge, while the fourth uses common sense to climb a tree. Knowledge without wisdom is dangerous.

  • "The Soul of the Great Bell" (China): Ko-Ngai sacrifices herself to molten metal to save her father, Kwan-Yu, after he fails twice to cast the emperor's bell.

Enhanced Science: Biological Systems

Digestive System

Stages: Ingestion $\rightarrow$ Digestion (Mechanical/Chemical) $\rightarrow$ Absorption $\rightarrow$ Assimilation $\rightarrow$ Elimination.

  • Organ Functions: Small Intestine (main site of absorption via Villi/Microvilli); Liver (Bile production); Large Intestine (Water absorption).

  • Mechanical Digestion: Churning and chewing.

  • Chemical Digestion: Enzymes and acids.

Excretory System

Responsibility: Remove metabolic waste to maintain Homeostasis.

  • Organs: Kidneys (filter blood), Ureters (transport), Bladder (storage), Urethra (expulsion).

Plant Systems

  • Xylem: Transports water/minerals upward.

  • Phloem: Transports glucose (food) throughout the plant.

  • Anatomy: Roots (absorption), Stem (support), Leaves (Photosynthesis via Stomata).

Enhanced Math: Measures and Polynomials

Central Tendency

  • Mean: Average of all values.

  • Median: Middle value when arranged sequentially.

  • Mode: Most frequent value.

Polynomial Operations

  • Addition/Subtraction: Combining like terms. For subtraction, use the KFC Method (Keep, Flip signs, Combine).

  • Multiplication:

    • FOIL Method: (First, Outer, Inner, Last) for binomials.

    • Distributive Property: a(b+c)=ab+aca(b+c) = ab + ac.

    • Special Products: (a+b)2=a2+2ab+b2(a+b)^2 = a^2 + 2ab + b^2 and (a−b)2=a2−2ab+b2(a-b)^2 = a^2 - 2ab + b^2.

  • Division:

    • Long Division: Standard algorithmic division.

    • Synthetic Division: Shortcut method for divisors of form (x−c)(x - c).

Electronic Tools and Components Test
Instructions: Answer all questions to the best of your ability. Each question is worth 2 points.

  1. What is the primary purpose of driving tools in electronics?
       a) Cutting materials
       b) Joining components
       c) Fastening screws and nuts
       d) Measuring current

  2. Which screwdriver has a straight blade?
       a) Phillips
       b) Slotted
       c) Torx
       d) Allen

  3. What type of screwdriver is known for its cross-shaped tip?
       a) Flat-head
       b) Stubby
       c) Phillips
       d) Torx

  4. The Jeweler's screwdriver set is used for:
       a) Heavy-duty applications
       b) Large mechanical devices
       c) Delicate electronics
       d) Wiring connections

  5. Which of the following tools is used to tighten hex nuts?
       a) Screwdriver
       b) Nut driver
       c) Pliers
       d) Drill

  6. What is the purpose of a soldering iron?
       a) Measure voltage
       b) Join electronic components
       c) Cut wires
       d) Strip insulation

  7. A soldering station typically includes:
       a) Only the soldering iron
       b) A heat-resistant stand
       c) Battery power source
       d) Wire cutters

  8. Which tool is used to remove molten solder from components?
       a) Desoldering wick
       b) Soldering iron
       c) Wire strippers
       d) Combination pliers

  9. What type of tool is a wire stripper?
       a) Cutting tool
       b) Driving tool
       c) Soldering tool
       d) Splicing tool

  10. A crimping tool is used for:
       a) Cutting thick cables
       b) Preparing wires
       c) Connecting wire terminals
       d) Stripping wire insulation

  11. The primary purpose of cutting tools is to:
       a) Join components
       b) Measure electricity
       c) Cut wires and materials
       d) Drill holes

  12. Which tool would be best for cutting metal rods?
       a) Utility knife
       b) Hacksaw
       c) Cable cutter
       d) Pin vise

  13. The purpose of a utility knife is to:
       a) Measure resistance
       b) Cut straight lines
       c) Join electrical parts
       d) Tighten screws

  14. What is a mini drill primarily used for?
       a) Large drilling tasks
       b) Precision work on PCBs
       c) Driving screws
       d) Cutting cables

  15. Which device provides a visual magnification for inspection?
       a) Digital multimeter
       b) Magnifying glass
       c) Helping hands
       d) Tweezers

  16. The anti-static wrist strap prevents:
       a) Electric shock
       b) Dust accumulation
       c) Electrostatic discharge
       d) Component overheating

  17. What is the purpose of a digital multimeter?
       a) To cut wires
       b) To measure electrical properties
       c) To join components
       d) To provide insulation

  18. The light sensor operates by varying its resistance based on:
       a) Heat
       b) Light intensity
       c) Pressure
       d) Motion

  19. An ultrasonic sensor measures distance by using:
       a) Light waves
       b) High-frequency sound waves
       c) Electric currents
       d) Heat signatures

  20. What characterizes an analog sensor?
       a) Produces binary signals
       b) Provides continuous electrical signals
       c) Works only with digital devices
       d) Measures only temperature

  21. Which sensor detects heat emitted by living organisms?
       a) Temperature sensor
       b) PIR motion sensor
       c) Humidity sensor
       d) Light sensor

  22. What does a pressure sensor measure?
       a) Sound levels
       b) Distance
       c) Forces exerted by gases or liquids
       d) Light intensity

  23. Which type of motor operates on alternating current?
       a) DC motor
       b) AC motor
       c) Servo motor
       d) Brushless DC motor

  24. A servo motor is known for:
       a) High speed
       b) Precision control
       c) Low torque
       d) Simplicity

  25. Which kind of motor rotates in small, precise steps?
       a) Brushless DC motor
       b) Stepper motor
       c) Universal motor
       d) Induction motor

  26. The term used for protecting sensitive electronic components from ESD is:
       a) Insulation
       b) Grounding
       c) Shielding
       d) Safety

  27. What does the term "solder" refer to in electronics?
       a) A type of wire
       b) A metal used to join components
       c) A kind of glue
       d) An electrical device

  28. Which tool is essential for cleaning circuit boards?
       a) Soldering iron
       b) Desoldering pump
       c) Paint brush
       d) Wire cutter

  29. A long-nose pliers is particularly useful for:
       a) Cutting wires
       b) Bending metal
       c) Gripping in tight spaces
       d) Sliding nuts

  30. What is one of the functions of the large intestine in the digestive system?
       a) Absorption of nutrients
       b) Water absorption
       c) Mechanical digestion
       d) Chemical digestion

  31. The main site of nutrient absorption in the digestive system is:
       a) Stomach
       b) Large intestine
       c) Small intestine
       d) Esophagus

  32. Which tool is specifically designed for holding workpieces during soldering?
       a) Helping hands
       b) Digital multimeter
       c) Tweezers
       d) Wire stripper

  33. Which type of sensor is used in automatic street lights?
       a) Humidity sensor
       b) Light sensor
       c) Pressure sensor
       d) Motion sensor

  34. What is the function of a gas detector?
       a) Measures temperature
       b) Detects presence of dangerous gases
       c) Measures humidity
       d) Detects sound waves

  35. Which type of motor is typically used in household appliances?
       a) Universal motor
       b) Stepper motor
       c) Brushless DC motor
       d) Servo motor

  36. What material does a soldering wick absorb?
       a) Air
       b) Dust
       c) Melted solder
       d) Water

  37. A hacksaw is best suited for cutting:
       a) Wood
       b) Metal
       c) Plastic
       d) Paper

  38. The crimping tool is used primarily for what purpose?
       a) To join parts together
       b) To tighten screws
       c) To cut wires
       d) To measure voltage

  39. Which type of drill is used for precision work on circuit boards?
       a) Portable electric drill
       b) Mini drill
       c) Hammer drill
       d) Electric screwdriver

  40. What is the primary implication of the term "homeostasis" in the excretory system?
       a) Cooking processes
       b) Balancing moisture levels
       c) Maintaining stable internal environment
       d) Nutrient absorption

  41. What are the components of the excretory system?
       a) Heart and lungs
       b) Kidneys, ureters, bladder, urethra
       c) Stomach and intestines
       d) Brain and neurons

  42. A touch sensor detects:
       a) Heat
       b) Light
       c) Physical contact
       d) Sound

  43. What does a tilt sensor measure?
       a) Temperature changes
       b) Orientation changes
       c) Light intensity
       d) Gas presence

  44. The function of the xylem in plant systems is to:
       a) Carry glucose
       b) Transport water/minerals
       c) Absorb sunlight
       d) Control leaf movements

  45. What role does phloem play in a plant?
       a) Transporting water
       b) Absorbing nutrients
       c) Distributing glucose
       d) Providing structural support

  46. A basic resistor in electrical circuits serves to:
       a) Increase current flow
       b) Control voltage levels
       c) Provide resistance to current
       d) Measure voltage

  47. The process of thermal conduction is fundamentally related to:
       a) Sound transmission
       b) Electrical resistance
       c) Heat transfer through materials
       d) Chemical reactions

  48. Which type of capacitor is typically used in power supply circuits?
       a) Ceramic capacitor
       b) Electrolytic capacitor
       c) Tantalum capacitor
       d) Film capacitor

  49. A multimeter can measure which of the following?
       a) Voltage only
       b) Current only
       c) Resistance only
       d) All of the above

  50. The critical feature of a circuit breaker is to:
       a) Provide constant current
       b) Automatically shut off to prevent overload
       c) Measure circuit resistance
       d) Enhance circuit efficiency

End of Test

  1. c) Fastening screws and nuts

  2. b) Slotted

  3. c) Phillips

  4. c) Delicate electronics

  5. b) Nut driver

  6. b) Join electronic components

  7. b) A heat-resistant stand

  8. b) Soldering iron

  9. b) Driving tool

  10. a) Cutting thick cables

  11. d) Cut wires and materials

  12. b) Hacksaw

  13. d) Cut straight lines

  14. b) Precision work on PCBs

  15. c) Magnifying glass

  16. b) Electrostatic discharge

  17. b) To measure electrical properties

  18. b) Light intensity

  19. b) High-frequency sound waves

  20. b) Provides continuous electrical signals

  21. a) Temperature sensor

  22. c) Forces exerted by gases or liquids

  23. b) AC motor

  24. c) Precision control

  25. b) Stepper motor

  26. d) Safety

  27. b) A metal used to join components

  28. c) Paint brush

  29. b) Bending metal

  30. b) Water absorption

  31. c) Small intestine

  32. a) Helping hands

  33. b) Light sensor

  34. b) Detects presence of dangerous gases

  35. a) Universal motor

  36. c) Melted solder

  37. b) Metal

  38. b) To tighten screws

  39. b) Mini drill

  40. c) Maintaining stable internal environment

  41. b) Kidneys, ureters, bladder, urethra

  42. c) Physical contact

  43. b) Orientation changes

  44. b) Transport water/minerals

  45. c) Distributing glucose

  46. c) Provide resistance to current

  47. c) Heat transfer through materials

  48. b) Electrolytic capacitor

  49. d) All of the above

  50. b) Automatically shut off to prevent overload