ELECTRONIC COMPONENTS

Electronics Components:

To have the flow and control of electrons we need to know the components used in electronics circuits.

There are passive and active components 

 

Passive electronic

Passive electronic components is don’t stimulate the electron & proton those that don’t have the ability to control current by means of another electrical signal.

Examples of passive electronic components are capacitors, resistors, inductors.

Active electronic

Active electronic components is a stimulated to the electron & proton those that can control the flow of electricity.

Most electronic printed circuit boards have at least one active component. Some examples of active electronic components are transistors, diode, silicon-controlled rectifiers (SCRs)

 

 

1.2 Description of basic components

Resistance: Unit is Ohms, Symbol is R or Ω. Resistance is a measure of how easily (or with what difficulty) electrons will flow through the device. 

Copper wire has a very low resistance, so a small voltage will allow a large current to flow.  Likewise, the plastic insulation has a very high resistance, and prevents current from flowing from one wire to those adjacent.  

Resistors have a defined resistance, so the current can be calculated for any voltage.  Resistance in passive devices is always positive (i.e. > 0)

 

Series resistance gives the increased value in its total equivalent resistance

R=R1+R2+R3+…

Parallel resistance gives the decreased value in its total equivalent resistance

1/R=1/R1+1/R2+1/R3+…

Ohm's law: Ohm's law describes the relationship between voltage, V , which is trying to force charge to flow, resistance, R , which is resisting that flow, and the actual resulting current I

Power: Power is the Electric energy produced per unit time.

Capacitor: We can say that a capacitor is a device used to store and release electricity, usually as the result of a chemical action. 

Unit: Farad (micro, nano, pico…)

Series capacitance gives the decreased value in its total equivalent capacitance

1/C=1/C1+1/C2+1/C3+…

Parallel capacitance gives the increased value in its total equivalent capacitance

C=C1+C2+C3+…

 

Also referred to as a storage cell, a secondary cell, a condenser or an accumulator. A Leyden Jar was an early example of a capacitor.

 

Inductors: An inductor is an electrical device (typically a conducting coil) that introduces inductance into a circuit. An inductor is a passive electrical component designed to provide inductance in a circuit. It is basically a coil of wire wrapped around an iron core. Simplest form an inductor is made up of a coil of wire.

 

The inductance measured in henrys, is proportional to the number of turns of wire, the wire loop diameter and the material or core the wire is wound around.

Series inductance gives the increased value in its total equivalent inductance

L=L1+L2+L3+…

Parallel inductance gives the decreased value in its total equivalent inductance

1/L=1/L1+1/L2+1/L3+…

Semiconductor devices: A conductor made with semiconducting material. Semiconductors are made up of a substance with electrical properties intermediate between a good conductor and a good insulator.

A semiconductor device conducts electricity poorly at room temperature, but has increasing conductivity at higher temperatures. Metalloids are usually good semiconductors.

Silicon: Silicon, atomic number 14 on the periodic table, is a semiconducting material from which integrated circuits (computer chips of all types--processors, memory chips, etc.; CCDs; transistors; etc.) are created.

Silicon is one of the most common elements. Silicon is also the semiconductor material out of which almost all modern transistors are made.

Diodes: A Diode is an electronic device that allows current to flow in one direction only. It is a semiconductor that consists of a p-n junction.

They are used most commonly to convert AC to DC, because they pass the positive part of the wave, and block the negative part of the AC signal, or, if they are reversed, they pass only the negative part and not the positive part.

Zener Diode:

A Zener diode is a particular type of diode that, unlike a normal one, allows current to flow not only from its anode to its cathode, but also in the reverse direction, when the so-called "Zener voltage" is reached. Zener diodes have a highly doped p-n junction.

The Zener diode is of 4V and the input DC power is of 9V. If a circuit output is connected across the zener then the output voltage level is showing what the Zener voltage is?

LED:

The Light emitting diode is a two-lead semiconductor light source. The LED is a special type of diode and they have similar electrical characteristics of a PN junction diode. Hence the LED allows the flow of current in the forward direction and blocks the current in the reverse direction. The LED occupies the small area which is less than the 1 mm2. 

The applications of LEDs used to make various electrical and electronic projects.

The lighting emitting diode is a p-n junction diode. It is a specially doped diode and made up of a special type of semiconductors. When the light emits in the forward biased, then it is called as a light emitting diode.

Transistor:

A transistor is a semiconductor device switch electronic signals and electrical power. It is composed of semiconductor material usually with at least three terminals for connection to an external circuit.

 When it works as an amplifier, it takes in a tiny electric current at one end (an input current) and produces a much bigger electric current (an output current) at the other.

Transistor of NPN & PNP type

Vise versa for pnp transistor in operation.

A PNP works in a same but opposite fashion. The base still controls current flow, but that current flows in the opposite direction – from emitter to collector. Instead of electrons, the emitter emits “holes” (a conceptual absence of electrons) which are collected by the collector.

Types of Transistors:

Series Circuit:

When two or more loads are connected serially, it is called series connection. The total voltage capacity of the power of load should be equal to the input supply.

A series circuit is a closed circuit in which the current follows one path, as opposed to a parallel circuit where the circuit is divided into two or more paths.

In a series circuit, the current through each load is the same and the total voltage across the circuit is the sum of the voltages across each load.

Parallel Circuit:

When two or more loads are interconnected at each terminal and finally connected with input supply, the circuit is called parallel circuit.

Voltage capacity of all the loads should be equal to the input supply. Load capacities of each load may vary.

Short Circuit:

Ø  When terminals of voltage source are interconnected, it is called short circuit.

Ø   Maximum current flows in the circuit in this situation.

Ø  Circuit gets short due to mutual contact of two conductor wires or if the lead is short.

Transformer:

One of the main reasons that we use alternating AC voltages and currents in our homes and workplace’s is that AC supplies can be easily generated at a convenient voltage, transformed (hence the name transformer) into much higher voltages and then distributed around the country using a national grid of pylons and cables over very long distances.

Where:

·           V_P  -  is the Primary Voltage

·           V_S  -  is the Secondary Voltage

·           N_P  -  is the Number of Primary Windings

·           N_S  -  is the Number of Secondary Windings

·           Φ (phi)  -  is the Flux Linkage

The reason for transforming the voltage to a much higher level is that higher distribution voltages implies lower currents for the same power and therefore lower I2R losses along the networked grid of cables. These higher AC transmission voltages and currents can then be reduced to a much lower, safer and usable voltage level where it can be used to supply electrical equipment in our homes and workplaces, and all this is possible thanks to the basic Voltage Transformer.

The Voltage Transformer can be thought of as an electrical component rather than an electronic component. A transformer basically is very simple static (or stationary) electro-magnetic passive electrical device that works on the principle of Faraday’s law of induction by converting electrical energy from one value to another.

The transformer does this by linking together two or more electrical circuits using a common oscillating magnetic circuit which is produced by the transformer itself. A transformer operates on the principals of “electromagnetic induction”, in the form of Mutual Induction.

Mutual induction is the process by which a coil of wire magnetically induces a voltage into another coil located in close proximity to it. Then we can say that transformers work in the “magnetic domain”, and transformers get their name from the fact that they “transform” one voltage or current level into another.

Transformers are capable of either increasing or decreasing the voltage and current levels of their supply, without modifying its frequency, or the amount of electrical power being transferred from one winding to another via the magnetic circuit.