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Semester 1: B.Sc Internet of Things
Fundamentals of Electronics: AC and DC Fundamentals, Resistors, Capacitors, Inductors, Series and parallel connections, Ohm's Law, KCL, KVL, Superposition theorem, Maximum power transfer theorem
Fundamentals of Electronics
AC and DC Fundamentals
AC (Alternating Current) is an electric current that reverses direction periodically, while DC (Direct Current) flows in a single direction. AC is commonly used in power supply systems, while DC is often used in batteries and electronic devices.
Resistors
Resistors are components that limit the flow of electric current in a circuit. They are characterized by their resistance value, measured in ohms. Resistors can be used in series or parallel to achieve desired resistance and current levels.
Capacitors
Capacitors store electrical energy in an electric field and release it when needed. They are measured in farads and play a crucial role in smoothing out voltage fluctuations in power supplies and timing applications.
Inductors
Inductors store energy in a magnetic field when current flows through them. They oppose changes in current, making them essential in filters, transformers, and oscillators.
Series and Parallel Connections
In a series connection, components are linked end-to-end, and the same current flows through all. In parallel, components share the same voltage but can conduct different amounts of current. Understanding these configurations is crucial for circuit design.
Ohm's Law
Ohm's Law states that the current (I) flowing through a conductor between two points is directly proportional to the voltage (V) across the two points and inversely proportional to the resistance (R). It can be expressed as V = I * R.
KCL (Kirchhoff's Current Law)
KCL states that the total current entering a junction equals the total current leaving that junction. This principle is fundamental in analyzing complex circuits.
KVL (Kirchhoff's Voltage Law)
KVL states that the sum of the electrical potential differences (voltage) around any closed circuit is zero. This law is essential for circuit analysis and understanding voltage drops.
Superposition Theorem
The superposition theorem states that in a linear circuit with multiple independent sources, the total current or voltage at any point is the algebraic sum of the currents or voltages caused by each source acting independently.
Maximum Power Transfer Theorem
This theorem states that to obtain maximum power from a source to a load, the resistance of the load must equal the resistance of the source. This principle is critical in optimizing circuit performance.
Semiconductors: Types, Energy band Structure, Working and characteristics of PN Junction Diode, BJT, JFET, MOSFET, LED, LDR, Solar Cell, Photo Diode
Semiconductors
Types of Semiconductors
Semiconductors are classified into two main types: intrinsic and extrinsic. Intrinsic semiconductors are pure forms of semiconductors with no significant doping, exhibiting limited conductivity. Extrinsic semiconductors are doped with impurities, which enhance their conductive properties. They are further categorized into n-type and p-type semiconductors. N-type semiconductors are doped with elements that have more valence electrons than the semiconductor material, leading to an abundance of free electrons. P-type semiconductors, on the other hand, are doped with elements having fewer valence electrons, creating 'holes' that act as positive charge carriers.
Energy Band Structure
The energy band structure of semiconductors consists of two main bands: the valence band and the conduction band. The valence band is filled with electrons, while the conduction band is typically empty in intrinsic semiconductors. The energy gap between these two bands is known as the band gap. In semiconductors, this band gap is small enough to allow electrons to jump from the valence band to the conduction band when energy is applied, enabling electrical conductivity.
PN Junction Diode
A PN junction diode is formed by joining p-type and n-type semiconductors. The interface between these materials creates a depletion region that acts as a barrier to charge carriers. When forward-biased, the diode allows current to flow, while reverse bias prevents it. Characteristics include the I-V curve showing exponential current increase in forward bias and minimal current in reverse.
Bipolar Junction Transistor (BJT)
BJTs are three-layer devices with two junctions, functioning as an amplifier or switch. They come in two types: NPN and PNP. The operation involves controlling the current flow from the collector to the emitter by a smaller current at the base, with parameters like current gain and active region defining their performance.
Junction Field Effect Transistor (JFET)
JFETs are voltage-controlled devices that operate on the principle of an electric field controlling the conductivity of a channel. They have high input impedance and are often used in amplifiers. Key characteristics include the transfer curve and output characteristics, which illustrate how gate voltage influences the drain current.
Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET)
MOSFETs are widely used in digital circuits due to their high switching speed and efficiency. They have three terminals: gate, drain, and source. The gate voltage controls the conductivity of an n-type or p-type channel between the drain and source. Characteristics include the transfer and output characteristics graphing drain current against gate voltage.
Light Emitting Diode (LED)
LEDs are semiconductor devices that emit light when current flows through them. They are made from direct bandgap materials, allowing electrons to recombine with holes, emitting energy in the form of photons. They are widely used in lighting and displays.
Light Dependent Resistor (LDR)
LDRs change resistance based on light intensity, making them useful in light-sensing applications. They typically have high resistance in darkness and low resistance in light, allowing them to function in applications like automatic lighting controls.
Solar Cell
Solar cells convert light energy into electrical energy through the photovoltaic effect. They typically consist of silicon-based semiconductors. When photons strike the cell, they energize electrons, allowing them to flow and generate electricity when connected to an external circuit.
Photo Diode
Photo diodes are semiconductors that convert light into electrical current. They operate in photoconductive mode or photovoltaic mode, with their sensitivity to light making them suitable for various applications, including optical communication and sensing.
Rectifiers and power supply: Half wave rectifier, full wave rectifier, bridge rectifier, Compression, Filters including Capacitor Filter, Inductor Filter, L section and π section filters
Rectifiers and Power Supply
Half Wave Rectifier
A half wave rectifier allows current to pass only during one half of the input signal cycle. It consists of a single diode connected in series with the load. The output voltage is pulsating DC which can be enhanced using filtering.
Full Wave Rectifier
A full wave rectifier utilizes both halves of the input AC signal, converting it into DC. It typically uses two diodes in a center-tapped transformer configuration or a full-bridge rectifier setup. The output is smoother compared to half wave rectification.
Bridge Rectifier
A bridge rectifier consists of four diodes arranged in a bridge configuration. It allows both halves of the AC waveform to be used, producing a higher output voltage and current efficiency without the need for a center-tapped transformer.
Compression
Compression in the context of power supplies refers to the process of reducing the voltage fluctuations and ripple in the output voltage. This is achieved through the use of filters and by selecting appropriate rectifier configurations.
Filters
Filters are essential in power supply design to smooth out the rectified output and eliminate high-frequency noise.
Capacitor Filter
A capacitor filter uses capacitors to store charge, smoothing out the output voltage after rectification. It charges when the rectified voltage is high and discharges when the voltage drops, thereby reducing ripple.
Inductor Filter
An inductor filter incorporates inductors that resist changes in current flow. This filter type tends to provide better suppression of ripple but is larger and may have voltage drop issues.
L Section Filter
An L section filter combines both capacitors and inductors in an L configuration. Typically, a capacitor is followed by an inductor to create a high-pass filter that smooths output voltage while suppressing ripple.
π Section Filter
The π section filter consists of an inductor between two capacitors, forming the shape of the Greek letter pi. This configuration offers excellent ripple suppression and is commonly used in power supplies.
Amplifier: Definition, feedback effects, Common emitter amplifier, Multistage amplifiers, RC Coupled amplifiers, Transformer coupled amplifier, Direct coupled amplifier, frequency response
Amplifier
Definition
An amplifier is an electronic device that increases the power, voltage, or current of a signal. It takes an input signal and produces a larger output signal.
Feedback Effects
Feedback in amplifiers can be positive or negative. Negative feedback reduces distortion and increases stability while positive feedback can enhance gain but may lead to oscillation.
Common Emitter Amplifier
A common emitter amplifier is a type of amplifier configuration that provides high gain. It inverts the input signal and is commonly used in single-stage amplifiers.
Multistage Amplifiers
Multistage amplifiers use multiple amplification stages combined to achieve higher gain. Stages can be arranged in different configurations to enhance performance.
RC Coupled Amplifiers
RC coupled amplifiers are connected using resistors and capacitors. They provide good frequency response and amplify signals over a wide frequency range.
Transformer Coupled Amplifier
Transformer coupled amplifiers use transformers for coupling between stages, which allows for impedance matching and signal isolation.
Direct Coupled Amplifier
Direct coupled amplifiers connect stages without any coupling elements. This configuration is used for low-frequency applications and provides wide bandwidth.
Frequency Response
The frequency response of an amplifier describes how the output signal amplitude varies with frequency. It is crucial for determining the amplifier's effectiveness across the intended frequency range.
