ixar Academy

Introduction To Electronics
Electronics can be defined as a branch of physics and engineering that deals with the study of
electron behavior, flow, and control under different conditions. In the study of electricity,
electrons flow through a conductor because they carry energy with them.
Definition of terms
Voltage: It is the amount of pressure required to move an electric charge (electrons) from one
point to another in an electrical circuit.
Current: It is the rate at which electrons flow past a point in a complete electrical circuit.
Power: It is the rate of transfer of electrical energy within a circuit.
Capacitance: It is the ability of a component or circuit to collect and store energy in the form of
an electrical charge.
Resistance: It is a measure of how much a material opposes the flow of electric current.
Short circuit: It is an unintended low-resistance path that allows current to flow directly between
two points in a circuit, bypassing the intended load.
Open Circuit: It refers to an electrical circuit where current fails to flow.
Polarity: The electrical polarity gives information about the direction of current through the
circuit.

Branches of electronics
 Digital electronics
 Analogue electronics
 Microelectronics
 Nano-electronics
 Optoelectronics
 Inter-grated circuits
 Semiconductor device

Basic Electrical Quantities

Voltage
Voltage is the pressure from an electrical circuit's power source that pushes charged electrons
(current) through a conducting loop, enabling them to do work such as illuminating a light. In
brief, voltage = pressure, and it is measured in volts (V).

Voltage is either alternating current (AC) voltage or direct current (DC) voltage. Ways they
differ are: Direct current voltage travels in a straight line, and in one direction only. It is
commonly produced by sources of stored energy such as batteries. Alternating current voltage
flows in evenly undulating since waves. AC is Commonly produced by utilities via generators,
where mechanical energy—rotating motion powered by flowing water, steam, wind or heat—is
converted to electrical energy. The output wave forms are shown as below.

Current
Current is the rate at which electrons flow past a point in a complete electrical circuit.
An ampere, or amp, is the international unit used for measuring current. It expresses the
quantity of electrons (sometimes called "electrical charge") flowing past a point in a circuit over
a given time. Electrons flow through a conductor (typically a metal wire, usually copper) when
two prerequisites of an electric circuit are met:
 1. The circuit includes an energy source (a battery, for instance) that produces voltage.
Without voltage, electrons move randomly and fairly evenly within a wire, and current
cannot flow. Voltage creates pressure that drives electrons in a single direction.
2. The circuit forms a closed, conducting loop through which electrons can flow, providing
energy to any device (a load) connected to the circuit. A circuit is closed (complete) when
a switch is turned to the ON, or closed, position
Current, like voltage, can be direct or alternating.
Direct current (dc): It flows only in one direction. Common source includes: batteries or dc
generator.
Alternating current (ac): It flows in a sine wave pattern (shown below); reverses direction at
regular intervals. Common source: household electrical receptacles powered by a public utility.

Resistance
Resistance is a measure of the opposition to the flow of current in an electrical circuit. Resistors
are devices designed to limit the amount of flow of current in a circuit. Resistance is measured in
ohms, symbolized by the Greek letter omega (Ω). To calculate the amount of current flowing in a
circuit we can use Ohm’s law which states that the voltage between two points is directly
proportional to the current passing through the resistance, and directly proportional to the
resistance of the circuit.
The formula for Ohm's law is V=IR. Where V is the voltage, I is the current through the circuit
and R is the resistance.
Worked Example:
Calculate the current in the circuit below
Solution:
According to Ohm’s law, V=IR
𝑉
Therefore; 𝐼 = 𝑅

We are given that V= 5V and R= 500Ω

5
So, 𝐼 = 500

=0.01A
So, by applying 5V potential a current of 0.01A flows through the 500 ohms resistor.
Example
Find the resistance in the circuit below:
Power
It is the rate at which electrical energy is transferred or used in a circuit, measured in watts (W).
Power can be calculated from the following equation: P =VI. By substituting the Ohm’s law we
can calculate as P= 𝐼 2 𝑅 where:

P=Power (W)
V=Voltage (V)
I=Current (A)
R=Resistance (Ω)
For example, a 60W rated light bulb uses 60 joules of energy per second.

Series and parallel circuits

In series circuits, components are connected end-to-end, creating a single path for current, so if
one component fails, the entire circuit breaks. In parallel circuits, components are connected
across each other, providing multiple paths for current, so if one component fails, the others can
still function. Below is a diagram demonstrating the difference between the two:

In series circuits: Current flows through each component sequentially, meaning there's only one
path for electricity to take. The current is the same throughout the entire circuit. The total voltage
of the source is divided among the components. The total resistance is the sum of all individual
resistances. If one component fails or is disconnected, the entire circuit stops working. Example
include Christmas lights connected in a single string.
In parallel circuits: Current can flow through different paths or branches, allowing multiple
components to operate independently. The total current entering the circuit is divided among the
branches, but the current in each branch is determined by the resistance in that branch. The
voltage across each component is the same as the source voltage. The total resistance is less than
the smallest individual resistance. If one component fails, the other components in the circuit
continue to operate.

Electronic Components
Resistors
A resistor is an electrical component that limits or regulates the flow of electrical current in an
electronic circuit. Resistors can also be used to provide a specific voltage for an active device
such as a transistor. Below are different types of resistors.
Applications
In electronic circuits, resistors provide a range of functions, such as:
 Reducing current flow
 Regulating signal levels
 Dividing voltages
 Biasing active components
Capacitors

Unlike the battery, a capacitor is a circuit component that temporarily stores electrical energy
through distributing charged particles on (generally two) plates to create a potential difference. A
capacitor can take a shorter time than a battery to charge up and it can release all the energy very
quickly. When connected to a cell or other power supply, electrons will flow from the negative
end of the terminal and build up on one plate of the capacitor. The other plate will have a net
positive charge as electrons are lost to the battery, resulting in a potential difference equivalent to
the voltage of the cell. A capacitor is characterized by its capacitance (C) typically given in units
Farad. The larger the capacitance, the more charge a capacitor can hold.
When a voltage is applied across the two conductors, an electric field forms in the dielectric.
This causes a positive charge to accumulate on one conductor and a negative charge on the other.
The capacitance of a capacitor is the ratio of the stored charge to the applied voltage, measured
in farads (F). Typical capacitors have capacitance values ranging from 1 picofarad (pF) (10^-12
F) to 1 millifarad (mF) (10^-3 F). The capacitance is directly proportional to the surface area of
the conductors and inversely proportional to the distance between them.
In practical use, there is a limit to the electric field strength that the dielectric can handle before
the capacitor breaks down. The conductors and their connections can introduce unwanted
inductance and resistance, affecting the capacitor's performance.
Applications
1. Energy Storage:
 Electronic Devices: Capacitors store and release electrical energy, enabling efficient
power management in devices like mobile phones, solar panels, and more.
 Power Supplies: They help stabilize power supply and reduce energy consumption.
  Renewable Energy: Capacitors are used in renewable energy installations to ensure
consistent electricity delivery.
 Pulsed Power: Capacitors are used as energy storage for applications requiring rapid
energy release, like in pulsed power applications.
2. Filtering:
 Electronic Noise Filtering: Capacitors can filter out unwanted noise and interference in
electronic circuits.
 Signal Processing: They are used to filter out unwanted frequencies and ensure that only
the desired signals are transmitted, particularly in communication systems and audio
equipment.
 Power Supply Filtering: Capacitors are used to smooth out voltage fluctuations in power
supplies, ensuring a cleaner DC output
3. Power Conditioning:
 Power Factor Correction: Power capacitors improve power factor by compensating for
reactive power, aligning current and voltage waveforms.
 Smoothing Current Fluctuations: Capacitors help power conditioners provide consistent
energy levels by smoothing current fluctuations.
 DC Power Source Reserve: Capacitors can act as a reserve for DC power sources,
providing a backup during voltage dips.
4. Timing Circuits:
 Time Delays and Oscillators: Capacitors can be combined with resistors to create time
delays and oscillators.
Inductors

An inductor, also known as a coil, choke, or reactor, is a passive electrical component that stores
energy in a magnetic field when current flows through it, opposing sudden changes in current.
Key Characteristics and Functions
 Energy Storage: Inductors store energy in the form of a magnetic field when current
flows through them.
 Opposition to Change: They oppose changes in current, meaning they resist sudden
increases or decreases in current flow.
 Inductance: Inductance (measured in Henries) is the property of an inductor that
describes its ability to store energy in a magnetic field.
 Construction: Inductors are typically made by winding a wire into a coil, often with a
core material to enhance the magnetic field.
Applications:
 Filtering: Inductors are used in filters to block AC signals while allowing DC signals to
pass through.
 Power Supplies: They are used in switching power supplies to store and transfer energy.
 Motors: Inductors are a key component in induction motors.
 Sensors: They can be used as sensors in various applications.
  Tuning Circuits: Inductors are used in tuning circuits in radio equipment.
 EMI Suppression: They are used to suppress electromagnetic interference (EMI).

Fuse
A fuse is an electrical safety device designed to protect circuits from overcurrent. They contain a
metal wire or strip that melts and breaks the circuit when excessive current flows, preventing
damage to components and reducing fire hazards.
The core of a fuse is a thin metal wire or strip that has a low melting point. When excessive
current flows through the circuit, the fuse wire heats up rapidly and melts, creating a gap in the
circuit and stopping the flow of electricity. After a fuse "blows," it must be replaced with a new
fuse of the same amperage rating. The Amperage rating of a fuse is always written on the fuse.
Diode
A diode is a two-terminal electronic component, typically made of semiconductor material like
silicon, that allows current to flow primarily in one direction (forward bias) while blocking it in
the opposite direction (reverse bias). Diodes are used to convert alternating current (AC) to direct
current (DC). They can protect circuits from reverse voltage or current. Light-emitting diodes
(LEDs) are a type of diode that emits light when current flows through them.

Intergrated circuit
An integrated circuit (IC), also known as a microchip or chip, is a small, flat piece of
semiconductor material, typically silicon, containing a multitude of interconnected electronic
components like transistors, resistors, and capacitors, that perform specific functions.

These components are interconnected through pathways etched onto the chip's surface, allowing
electrical signals to flow between them and enabling the IC to perform various functions. The
key components of an IC include:
  Transistors: Act as electronic switches or amplifiers.
 Resistors: Limit the flow of current.
 Capacitors: Store electrical energy.
 Diodes: Allow current to flow in one direction.
ICs are used in a wide range of electronic devices, including computers, smartphones,
televisions, inverters and other electronic equipment. All ICs are polarized, and every pin is
unique in terms of both location and function. This means the package has to have some way to
convey which pin is which. Most ICs will use either a notch or a dot to indicate which pin is the
first pin. (Sometimes both, sometimes one or the other.)
Component symbols and identification

Basic terminology for technicians

L.C.D - Liquid Crystal Display.
I.C -Integrated Circuit.
O.S - Operating System.
App -Application.
RAM -Random Access Memory
ROM - Read-Only Memory.
PCB - Printed Circuit Board.
CPU - Central Processing Unit.
GPU -Graphics Processing Unit.
OLED - Organic Light-Emitting Diode.
AMOLED - Active-Matrix Light-Emitting Diode.
RTC: Real Time Clock
LED: Light Emitting Diode
PFO: Power Frequency Oscillator
ESD: Electro Static Discharge