Basic Electronics Master Guide: Complete Information on 35+ Components

 

I. Passive Components

These components do not generate energy; instead, they control or store it.

Resistor

• Working: It restricts (resists) the flow of electrons, converting electrical energy into heat.

• Example: If you have a 9V battery and a 2V LED, a resistor is placed in between to lower the voltage and prevent the LED from burning out.

Capacitor

• Working: It consists of an insulator (Dielectric) between two conducting plates. It resists sudden changes in voltage by storing energy.

• Example: When a ceiling fan continues to spin for a few seconds after a power cut or inverter switch, it is due to the energy stored in the capacitor.

Inductor

• Working: When current flows through a coil of wire, a magnetic field is created. It resists sudden changes in current.

• Example: Small inductors inside mobile chargers are used to filter out electrical 'noise'.

Potentiometer (Variable Resistor)

• Working: It features a sliding contact. Rotating it changes the length of the resistive track, thereby increasing or decreasing the voltage.

• Example: The volume knob on a radio or the rotary regulator on older fans.

Transformer

• Working: It operates on the principle of Mutual Induction. It steps up (increases) or steps down (decreases) voltage without changing the frequency.

• Example: The transformer on a utility pole converts 11,000V to 230V for home use.
  
  

II. Semiconductor Components

These components make modern gadgets (Smartphones, Laptops) possible.

P-N Junction Diode

• Working: It allows current to flow in one direction (Forward Bias) and blocks it in the other (Reverse Bias).

• Example: Used in battery chargers to ensure current flows into the battery but not back into the socket.

Zener Diode

• Working: It allows current to flow in the reverse direction only after reaching a specific fixed voltage (Zener Voltage).

• Example: Used in voltage stabilizers to maintain a fixed output voltage.

LED (Light Emitting Diode)

• Working: When electrons cross the P-N junction, they release energy in the form of photons (light).

• Example: Household LED bulbs and TV backlights.

Bipolar Junction Transistor (BJT)

• Working: This is a 'Current Controlled' device. A small current applied to the Base controls a larger current flowing from the Collector to the Emitter.

• Example: Used in audio amplifiers to boost sound.

MOSFET

• Working: This is a 'Voltage Controlled' device. It consumes very little power and can switch very rapidly.

• Example: Millions of MOSFETs act as switches inside laptop processors.

IGBT (Insulated Gate Bipolar Transistor)

• Working: A hybrid of BJT and MOSFET. It combines the control characteristics of a MOSFET with the high-power handling of a BJT.

• Example: Used in electric locomotives (trains) and induction cooktops.

SCR (Silicon Controlled Rectifier)

• Working: A 'Latching' device. Once triggered, it remains on until the current supply is cut off.

• Example: Used in motor controllers for heavy machinery.

TRIAC

• Working: Similar to two SCRs connected inversely; it can control AC current in both directions.

• Example: Digital fan regulators and light dimmers.

DIAC

• Working: It allows current to flow in both directions only after a specific voltage (Breakover voltage) is reached.

• Example: Primarily used to trigger (fire) a TRIAC.

Schottky Diode

• Working: It has a much lower voltage drop ($0.15V-0.45V$) compared to standard diodes and operates very fast.

• Example: Used in solar panel circuits and high-frequency switching.

Integrated Circuit (IC)

• Working: Resistors, transistors, and capacitors are fabricated at a microscopic level onto a single silicon chip.

• Example: The 555 Timer IC used for timing and pulse generation.

III. Protection & Switches

Relay

• Working: Operates on the principle of electromagnetism. It allows a small DC signal to switch a high-voltage (220V AC) circuit.

• Example: The "click" sound heard in a fridge stabilizer when voltage fluctuates is the relay switching.

Optocoupler

• Working: Contains an LED and a photo-transistor inside. It transmits electrical signals via light to isolate circuits and protect against high voltage.

• Example: Used in computer power supplies (SMPS).

Fuse

• Working: A wire made of a metal with a low melting point. It melts due to heat when excessive current flows, breaking the circuit.

• Example: Used for safety in electrical boards or car dashboards.

MCB (Miniature Circuit Breaker)

• Working: Operates on thermal or electromagnetic principles. Unlike a fuse, it doesn't burn out; it simply "trips" (switches off) and can be reset.

• Example: Used in modern household wiring protection.

Push Button (Momentary Switch)

• Working: Spring-loaded mechanism. The circuit connects when pressed and breaks when released.

• Example: Calculator buttons or elevator buttons.

Varistor (MOV)

• Working: Its resistance drops suddenly when high voltage occurs, diverting the excess electricity to the ground.

• Example: Protects TVs or computers from burning out during lightning strikes or surges.

IV. Sensors & Output

LDR (Light Dependent Resistor)

• Working: Based on photo-conductivity. As light intensity increases, electrons increase, and resistance decreases.

• Example: Automatic street lights that turn on at night.

Thermistor (NTC/PTC)

• Working: A temperature-sensitive resistor. In NTC (Negative Temperature Coefficient), resistance decreases as heat increases.

• Example: Thermal protection that shuts down a mobile phone when the battery overheats.

PIR Sensor

• Working: Detects infrared radiation (heat) emitted by humans or animals.

• Example: Anti-theft burglar alarms.

Ultrasonic Sensor

• Working: Emits ultrasonic waves and measures the time it takes for them to bounce back ($Speed=Distance/Time$).

• Example: Self-driving cars and obstacle avoidance in drones.

Crystal Oscillator

• Working: Uses the Piezoelectric Effect to provide a precise frequency to a circuit.

• Example: Used for timing in wristwatches and determining computer clock speeds.

Buzzer (Piezoelectric)

• Working: When voltage is applied, a crystal plate inside vibrates, producing sound.

• Example: The reversing sound in cars.

7-Segment Display

• Working: Consists of 8 LEDs arranged in a specific pattern (Segments A to G and a decimal point).

• Example: Digital watches or petrol pump meters.

LCD (Liquid Crystal Display)

• Working: Liquid crystals polarize light to display characters or images.

• Example: The screen of a digital multimeter.

V. Miscellaneous

Microphone (Condenser)

• Working: Sound waves vibrate a diaphragm, changing capacitance and creating an electrical signal.

• Example: Mobile phone microphones.

Solenoid Coil

• Working: When current flows through it, magnetism is created that pulls a metal plunger inward.

• Example: Used to open/close water valves in washing machines.

Heat Sink

• Working: Disperses component heat into the air via thermal conductivity.

• Example: The aluminum structure mounted on top of a computer processor.

Voltage Regulator (78XX Series)

• Working: Converts excess voltage into heat to provide a perfectly stable output (e.g., 5V).

• Example: Inside mobile charger circuit boards.

Battery (Li-ion/Lead Acid)

• Working: Creates a flow of electrons through a chemical reaction.

• Example: Mobile phone batteries and home inverter batteries.