Zener Diode

A Zener Diode is a special kind of diode which permits current to flow in the forward direction as normal, but will also allow it to flow in the reverse direction when the voltage is above the breakdown voltage or ‘zener’ voltage. Zener diodes are designed so that their breakdown voltage is much lower - for example just 2.4 Volts.

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Structure of Bipolar Junction Transistor

A bipolar junction transistor, BJT, is a single piece of silicon with two back-to-back P-N junctions.BJTs can be made either as PNP or as NPN.

They have three regions and three terminals, emitter, base, and collector represented by E, B, and C respectively. The direction of the arrow indicates the direction of the current in the emitter when the transistor is conducting normally. An easy way to remember this is NPN stands for "Not Pointing iN".

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Rectification


A rectifier is a device that converts alternating current (AC) to direct current (DC), a process known as rectification. Rectifiers are essentially of two types – a half wave rectifier and a full wave rectifier.

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Op-Amp(Operational Amplifier)



Operational Amplifier commonly known as Op-Amp, is a linear elcectronic device having three terminals, two high impedence input and one output terminal



Op-Amp can perform multiple function when attached to diffrent feedback combinations like resistive,
capacitive or both.

Generally it is used as voltage amplifier and the output voltage of the Op-Amp is the diffrence between the voltages at its two input terminals.


Op-Amp shows some properties that make it an ideal amplifier,
its open loop gain and input impedance is infinite (i.e.,practically very high), Output impedance and offset voltage is zero(i.e.,practically very low) and bandwidth is infinite(i.e.,practically limitted to frequency where its gain become unity).

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Inverting Op-Amp

The open loop gain(Ao) of the Om-Apm is very high which makes it very unstable, so to make it stable with a controlable gain, a feed back is applied through some external resistor(Rf) from its output to inverting input terminal(i.e.,also known as negative feedback) resulting in reduced gain(closed loop gain, Av).

So the voltage at inverting terminal is now the sum of the actual input and feedback voltages, and to separate both a input resistor(Ri) is introduced in the circuit. The non inverting terminal of the opamp is grounded, and the inverting terminal behaves like a virtual ground as the junction of the input and feedback signal are at the same potential.

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Non-Inverting Op-Amp


In this configuration of Op-amp the input signal is directly fed to the non inverting terminal resulting in a positive gain and output voltage in phase with input as compared to inverting Op-amp where the gain is negative and output voltage is out of phase with input , and to stabalize the circuit a negative feedback is applied through a resistor(Rf) and the inverting terminal is grounded witha input resistor(R2).

This inverting Op-Amp like layout the at inverting terminal creates a virtual ground at the summing point make the Rf and R2 a potential divider accross inverting terminal, Hence determines the gain of the circuit.

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What is a Schmitt Trigger?

A Schmitt trigger is a comparator (not exclusively) circuit that makes use of positive feedback (small changes in the input lead to large changes in the output in the same phase) to implement hysteresis (a fancy word for delayed action) and is used to remove noise from an analog signal while converting it to a digital one.

It was invented way back in 1937 by Otto H. Schmitt (whose legacy is somewhat understated) who called it a ‘thermionic trigger’.

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Designed to accurately produce the required output waveform with the addition of just a few extra timing components.

One such device that has been around since the early days of IC’s and has itself become something of an industry “standard” is the 555 Timer Oscillator which is more commonly called the “555 Timer”.

The basic 555 timer gets its name from the fact that there are three internally connected 5kΩ resistors which it uses to generate the two comparators reference voltages. The 555 timer IC is a very cheap, popular and useful precision timing device which can act as either a simple timer to generate single pulses or long time delays, or as a relaxation oscillator producing a string of stabilised waveforms of varying duty cycles from 50 to 100%.

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What is a laser diode?

👉The LASER in Laser Diode is an acronym for 'Light Amplification by Stimulated Emission of Radiation'. It is also referred to as a semiconductor laser and generally abbreviated as LD.

👉Its main feature is high coherency, making it possible to emit light with the same phase and wavelength.

👉Laser oscillation is achieved by amplifying light generated through current injection between two mirrors. Simply put, a laser diode is an LED that amplifies and emits light using reflectors.

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What is wireless charging?

👉Wireless charging is a technology that charges devices without using connectors or metal contacts.

👉This is also referred to as non-contact charging, non-contact power transmission, and wireless power supply.

👉Wireless charging technology is attracting increased attention by eliminating the need for power cords when charging.

👉 This is expected to increase connector safety and resistance to dust and water while enabling multiple devices to be charged using a single charger.

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Decibels
Unit is Bel, but because this is large, deci-Bels (1/10th Bel) are used), Symbol is dB.

Decibels are used in audio because they are a logarithmic measure of voltage, current or power, and correspond well to the response of the ear.

A 3dB change is half or double the power (0.707 or 1.414 times voltage or current respectively).
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Cathode Ray Tube

CRT

Cathode ray tube display technology is mostly used in televisions and computer screens that work on the movement of an electron beam back and forth on the back of the screen. This tube is an elongated vacuum tube in which the flattened surface has external components as an electron gun, electron beam, and a phosphorescent screen

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The Differential Amplifier

The differential amplifier amplifies the voltage difference present on its inverting and non-inverting inputs

differential amplifiers amplify the difference between two voltages making this type of operational amplifier circuit a Subtractor unlike a summing amplifier which adds or sums together the input voltages. This type of operational amplifier circuit is commonly known as a Differential Amplifier configuration

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Wheatstone bridge

Wheatstone bridge, also known as the resistance bridge, calculates the unknown resistance by balancing two legs of the bridge circuit. One leg includes the component of unknown resistance.


The Wheatstone Bridge Circuit comprises two known resistors, one unknown resistor and one variable resistor connected in the form of a bridge. This bridge is very reliable as it gives accurate measurements.

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Kirchhoff’s Current Law


According to Kirchhoff’s Current Law,

The total current entering a junction or a node is equal to the charge leaving the node as no charge is lost.

Put differently, the algebraic sum of every current entering and leaving the node has to be null. This property of Kirchhoff law is commonly called Conservation of charge wherein, I(exit) + I(enter) = 0.

In the above figure, the currents I1, I2 and I3 entering the node is considered positive, likewise, the currents I4 and I5 exiting the nodes is considered negative in values. This can be expressed in the form of an equation:

I1 + I2 + I3 – I4 – I5 = 0

The term Node refers to a junction or a connection of two or more current-carrying routes like cables and other components.

Kirchhoff’s current law can also be applied to analyze parallel circuits.

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Kirchhoff’s Voltage Law


According to Kirchhoff’s Voltage Law,

The voltage around a loop equals to the sum of every voltage drop in the same loop for any closed network and also equals to zero.

Put differently, the algebraic sum of every voltage in the loop has to be equal to zero and this property of Kirchhoff’s law is called conservation of energy.

When you begin at any point of the loop and continue in the same direction, note the voltage drops in all the directions either negative or positive and return to the same point. It is essential to maintain the direction either counterclockwise or clockwise; else the final voltage value will not be equal to zero. The voltage law can also be applied in analyzing circuits in series.

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Quality Factor


The quality factor or Q factor is a measure of the performance of a coil, capacitor inductor in terms of its losses and resonator bandwidth. Simple formulas can relate the variables.

The definition of quality factor is often needed to give a more exact understanding of what this quantity actually is.

For electronic circuits, Q is defined as the ratio of the energy stored in the resonator to the energy supplied by a to it, per cycle, to keep signal amplitude constant, at a frequency where the stored energy is constant with time.

It can also be defined for an inductor as the ratio of its inductive reactance to its resistance at a particular frequency, and it is a measure of its efficiency.

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Lines of Force from a Bar Magnets Magnetic Field

However, magnetic flux does not actually flow from the north to the south pole or flow anywhere for that matter as magnetic flux is a static region around a magnet in which the magnetic force exists. In other words magnetic flux does not flow or move it is just there and is not influenced by gravity. Some important facts emerge when plotting lines of force:

✅ Lines of force NEVER cross.

✅ Lines of force are CONTINUOUS.

✅ Lines of force always form individual CLOSED LOOPS around the magnet.

✅ Lines of force have a definite

✅ DIRECTION from North to South.

✅ Lines of force that are close together indicate a STRONG magnetic field.

✅ Lines of force that are farther apart indicate a WEAK magnetic field.

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Passive Attenuators
A Passive Attenuator is a special type of electrical or electronic bidirectional circuit made up of entirely resistive elements.

👉An attenuator is a two port resistive network designed to weaken or “attenuate” (hence their name) the power being supplied by a source to a level that is suitable for the connected load.

👉It reduces the amount of power being delivered to the connected load by either a single fixed amount, a variable amount or in a series of known switchable steps.
These are generally used in radio, communication and transmission line applications to weaken a stronger signal.

👉It is a purely passive resistive network (hence no supply) which is used in a wide variety of electronic equipment for extending the dynamic range of measuring equipment by adjusting signal levels, to provide impedance matching of oscillators or amplifiers to reduce the effects of improper input/output terminations, or to simply provide isolation between difference

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