Electricity

Electricity is a form of energy, that is generated by movement of charged particles, such as electrons. It is a fundamental part of our daily lives, powering everything from homes and business, devices to vehicles.

Electrical Quantities

Voltage

The difference in potential between two point in a circuit is termed as the voltage or potential difference. SI unit of voltage is Volt (V).

Current

The rate of flow of electric charge in circuit is termed as the electric current. It is measured in Ampere (A). It is the affect of voltage.

Resistance

Resistance is the opposition to the flow of electric current through a conductor. It is measured in Ohms, and depends on the material length and cross sectional area of the conductor.

Active Components

Active components are the electronic components that can control the flow of electrical current and perform specific functions, such as amplification, switching, and signal processing. They require an external power source to operate and are capable of modifying the electrical signal in some way.

Diodes

P-N junction diodes

A P-N junction is a type of semiconductor device that consists of two types of materials, P-type (positive) and N-type (negative), joined together at a junction.

The P-type material has an excess of holes (positive charge carriers), while the N-type material has excess of electrons (negative charge carriers).

Working

• Depletion region: When the P-type and N-type materials are join, the electrons from N-type diffuse into the P-type material creating a depletion region around the junction.

• Electric field: The depletion region creates an electric field that opposes the flow of electrons from the N-type material to the P-type material.

• Current flow: When a voltage is applied across the P-N junction, the electric field is overcome, and current flows through the junction.

Biasing conditions

Forward biasing

When the P-type semiconductor is connected to the positive terminal of the voltage source and the N-type semiconductor is connected to the negative terminal, then the junction is said to forward biased.

In this condition, the depletion region gets thinner, and as result, it supports the flow of current.

Reverse biasing

When the N-type semiconductor is connected to the positive terminal of the voltage source and the P-type semiconductor is connected to the negative terminal, then the junction is said to forward biased.

In this condition, the depletion region gets wider,and as result it opposes the flow of current.

Transistors

It's a type of semiconductor device that can amplify or switch electronic signals. It's essentially a device that can control the flow of electric current.

BJT

It stands for Bipolar Junction Diode. It's a three terminal semiconductor device that is able to amplify or switch the electrical signal or power.

It is constructed with three doped semiconductor regions named as base, collector and emitter, seperated by two P-N junctions.

Types of BJT

1. P-N-P BJT

   In this BJT, the N-type semiconductor is placed between the two P-type semiconductors that acts as emitter and collector while the N-type semiconductor acts as base.

   The current enters into the transistor through the emitter such that the emitter-base junction is reverse-biased.

2. N-P-N BJT

   In this BJT, the P-type semiconductor is placed between the two N-type semiconductors that acts as emitter and collector while the P-type semiconductor acts as base.

   The current enters into the transistor through the emitter such that the emitter-base junction is forward-biased.

Applications of BJT

• Used as amplifier

• Can function as a switch

• Used as an oscillator

• Used in logic circuits

• Used as demodulator

• Used in temperature sensor

MOSFET

MOSFET stands for Metal Oxide Semiconductor Field Effect Transistor.

It is a voltage controlled, high speed switching device that is used in switching devices like choppers, amplifications, and in voltage regulations.

It has three terminals which includes drain, gate and source.

Construction

• The base is formed of a P-types semiconductor.

• It's two types of bases are highly dropped with an N-type of impurity.

• The terminals, source, and drain originated from the heavily doped region of the base.

• The substrate layer is coated with a layer of insulating silicon dioxide (SiO2).

• On the top of silicon dioxide, a thin insulated metal plate is kept, which acts as a capacitor in the MOSFET.

• From the thin metallic plate, the gate terminal is brought out.

• A DC circuit is formed when a voltage source is connected between these two doped N-type regions.

Applications of MOSFET

• Can be used as switch to control the flow of current

• Can be used as amplifier to increase the strength of a signal

• Used as invertor

• Used as brushless DC motor drives

• Used in SMPS.

Passive Components

Passive components are the electrical components that do not require an external power source to operate and cannot control the flow of electric current. They are used to store energy, filter signals, and provide impedance in electronic circuits.

Resistor

It's a passive electronic component that opposes the flow of electric current. It reduces the voltage and current in a circuit by converting some of the energy into heat.

Capacitor

A capacitor is a type of electronic 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.

Inductor

An inductor is a type of passive electronic component that store the energy in the form of magnetic field. It's essentially a coil of wire wrapped around of a core material.

Tranformer

It's an electrical device that transfers electrical energy from one circuit to another through electromagnetic induction. It consists of two coils of wire, known as the primary and secondary coils, which are wrapped around a common magnetic core.

Types

• Step-up transformer: Increases the voltage from primary coil to the secondary coil.

• Step-down transformer: Decrease the voltage from primary coil to the secondary coil.

• Auto-transformer: Have only one coil that servers as both primary coil and secondary coil.

• Isolation transformer: Provide electrical isolation between primary coil and secondary coil.

Sensor

A sensor is a device that detects and measures physical or environmental parameters, such as temperature, pressure, light, motion or sound and convert them into electrical signals, that can be processed and analyzed.

Types

1. Light sensor

2. Temperature sensor

3. Pressure sensor

4. Motion sensor

5. Proximity sensor

6. Humidity sensor

7. Sound sensor

8. Gas sensor

Transducer

It's a device that converts the energy from one form to another form. In the context of electrical engineering transducer is typically used to convert physical quantities such as pressure, temperature, vibrations into electrical signal.

Integrated Circuits

An integrated circuit (IC) compact collection of electrical circuits on a small, flat piece of semiconductor material, usually silicon. ICs are the building blocks of modern electronics and are used in a wide range of applications from simple consumer devices to industrial and medical systems.

Types of ICs

1. Digital ICs: Perform logical operations using binary codes (0s &1s).

2. Analog ICs: Process continuous signals, such as audio or video.

3. Mixed-signal ICs: Combines the digital and analog functions.

4. Microprocessors: Central processing unit (CPU) that executes software operations.

Applications

• ICs are the heart of modern computing and communication devices

• Used in TVs, audio equipments and other consumer devices.

• Used in medical imaging, patient monitoring.

• Used in automation, robotics and process control.

Digital Electronics

Digital electronics involves the use of electronic circuits and devices to process, store, and transmit information in digital form which is represented by binary numbers (0s and 1s).

PWM

Pulse Width Modulation (PWM) is a technique used to encode a message into a pulsing signal. It involve modifying the width of the pulse in a carrier signal to encode information.

Working

• Carrier signal: A high-frequency carrier signal is generated.

• Pulse width: The width of the pulse in the carrier signal is modified to encode the signal.

• Modulation: The pulse width is varied in accordance with the information to be transmitted.

Applications

• Used to control the speed if DC motors.

• Used to regulate the output voltage of power supplies.

• Used in audio equipments, such as amplifiers and effect processors.

• Used to control the brightness of LEDs and other lighting system.

• Used in communication system, such as radio transmitters and receivers.

Optocoupler

An optocoupler, also known as an opto-isolator, is an electronic component that uses light to transfer signals between two isolated circuits. It consists of a light-emitting diode (LED) and a photodetector, such as a phototransistor photodiode, enclosed in a single package.

Applications

• Used to provide isolation between the input and output of power supplies.

• Used to isolate data transmission lines from electrical noise.

• Used to provide isolation between the control circuit and motor.

• Used in medical devices, such ad defibrillators and patient monitors, to provide electrical isolation.

Checking AC to DC converter

Visual inspection

• Verify that the convertor had no visible signs of physical damage, such as cracks, burns, or broken components.

• Ensure that all connections, including input and output wires, are secure and not loaded

Electrical test

• Measure the input voltage to ensure it matches the converter’s specifications.

• Measure the output voltage to ensure it matches the converter’s specifications.

• Measure the output current to ensure it is within the converter’s specifications.

• Measure the converter’s efficiency by comparing the input and output power.

• Measure the rippel and noise on the output voltage to ensure it is within acceptable limits.

Conclusion

This is just an overview of basic electronics. There are lot more to know that how exactly an electronic device works.