Basic Electronic Components II

Basic Electronic Components  II

Resistor

 

A resistor is a two-terminal electrical component that opposes the flow of electric current. It is a fundamental component used in electronic circuits, and it is designed to reduce the voltage and current in a circuit by converting some of the electrical energy into heat.

Types of Resistors:

1. Fixed Resistors: Have a fixed resistance value.

2. Variable Resistors: Allow for adjustable resistance values.

3. Linear Resistors: Have a linear relationship between voltage and current.

4. Non-Linear Resistors: Have a non-linear relationship between voltage and current.

Key Functions of a Resistor:

1. Limit Current: Resistors help protect delicate components in a circuit by preventing too much current from flowing through them.
2. Voltage Divider: Resistors can be combined to divide the voltage in a circuit.
3. Control Power: By dissipating electrical energy as heat, resistors play a role in managing the power used by circuits.

How It Works:

When a voltage (electric potential) is applied across a resistor, the resistance of the resistor causes the current to decrease. The relationship between voltage (V), current (I), and resistance (R) is described by Ohm's Law, which states:

                                                               V=I×R                 

Where:

• V is the voltage (in volts)
• I is the current (in amperes)
• R is the resistance (in ohms, Ω)

Symbol:

Applications of Resistors:

1. Electronic Circuits: Used in various electronic circuits, such as amplifiers and filters.

2. Power Supplies: Used to regulate voltage and current levels.

3. Measurement Instruments: Used in measurement instruments, such as multimeters and oscilloscopes.

4. Automotive Systems: Used in automotive systems, such as anti-lock braking systems (ABS).

Capacitors

A capacitor is a two-terminal electrical component that stores energy in the form of an electric field. It consists of two conductive plates separated by a dielectric material, such as air, ceramic, or a polymer film and it is widely used for various purposes in circuits, such as energy storage, filtering, and smoothing signals.

Types of Capacitors:

1. Ceramic Capacitors: Use ceramic as the dielectric material.

2. Film Capacitors: Use a polymer film as the dielectric material.

3. Electrolytic Capacitors: Use an electrolyte as the dielectric material.

4. Tantalum Capacitors: Use tantalum as the dielectric material.

5. Super Capacitors: Also known as ultra-capacitors or electrochemical capacitors.

Key Characteristics of a Capacitor:

1. Capacitance: The amount of electrical charge a capacitor can store is measured in farads (F). The capacitance is directly proportional to the surface area of the plates, the distance between them, and the material (dielectric) between the plates.   
2. Dielectric: The material between the two plates of a capacitor is called the dielectric. It can be air, ceramic, paper, plastic, or other materials, and it affects the capacitor’s ability to store charge.          
3. Charge and Discharge: Capacitors can charge up to the applied voltage and then discharge their stored energy when needed. They don’t allow direct current (DC) to pass through them but can pass alternating current (AC) due to their ability to charge and discharge with changes in voltage.

Formula for Capacitance:

The amount of charge (Q) stored on the capacitor is related to the capacitance (C) and the voltage (V) across it by the formula:

                                                                  Q=C×V

Where:

• Q is the charge (in coulombs)
• C is the capacitance (in farads)
• V is the voltage (in volts)

Symbol:

Applications of Capacitors

1. Power Supplies: Used to filter and regulate voltage levels.

2. Audio Equipment: Used to filter and couple audio signals.

3. Radio Transmitters: Used to couple and decouple radio signals.

4. Medical Devices: Used in medical devices, such as defibrillators and pacemakers.

5. Automotive Systems: Used in automotive systems, such as airbag systems and anti-lock braking systems (ABS).

Inductor

An inductor is a two-terminal passive electrical component that stores energy in the form of a magnetic field. It consists of a coil of wire wrapped around a core material, such as air, iron, or ferrite.

Types of Inductors:

1. Air-Core Inductors: Use air as the core material.

2. Iron-Core Inductors: Use iron as the core material.

3. Ferrite-Core Inductors: Use ferrite as the core material.

4. Toroidal Inductors: Use a toroidal (doughnut-shaped) core.

5. Chip Inductors: Small, surface-mount inductors.

Key Characteristics of an Inductor:

1. Inductance (L): The ability of an inductor to store energy in its magnetic field is measured by its inductance, which is measured in henries (H). The inductance depends on factors such as the number of turns in the coil, the material of the core (if any), and the dimensions of the coil.

1. Magnetic Field: When current flows through the wire of the inductor, it creates a magnetic field around it. The inductor resists changes in current due to this magnetic field, which is a key property that makes inductors useful in circuits.

1. Impedance: Inductors oppose changes in current by generating an opposing voltage (called self-induced voltage) as the current changes. This characteristic is described as inductive reactance, and it increases with frequency in AC circuits. This is why inductors are used in applications like filters and transformers.

How It Works:

When the current through an inductor changes, the magnetic field around it changes as well. According to Faraday's Law of Induction, a change in the magnetic field induces a voltage (electromotive force, or EMF) in the coil, which opposes the change in current. This is known as Lenz's Law.

Formula for Inductance:

The voltage across an inductor is given by the formula:

                                                                  V=L×dI/dt

Where:

• V is the voltage across the inductor (in volts)
• L is the inductance (in henries)
• dI/dt is the rate of change of current (in amperes per second)

This means that the voltage across an inductor is proportional to the rate at which the current through it is changing.

Symbol:

Applications of Inductors:

1. Power Supplies: Used to filter and regulate voltage levels.

2. Audio Equipment: Used to filter and couple audio signals.

3. Radio Transmitters: Used to couple and decouple radio signals.

4. Medical Devices: Used in medical devices, such as MRI machines and pacemakers.

5. Automotive Systems: Used in automotive systems, such as ignition systems and fuel injectors.