Basics of Electronic Engineering

Here we are going to discuss about what is electronics. In my experience, when I ask what is electronics there is a tendency for many ones that electronics is the flow of electrons. It is a blunder answer. The flow of electrons is called as the Electricity. Actually electronics is a branch of science which can be defined by the institution of radio engineers as:” The field of science and engineering, which deals with electron devices and their utilization”. The electron devices are those devices where the electricity (current) flow is mainly due to the flow of charge carriers in a controlled manner through a gas, a vacuum or a semiconductor. In the earlier stages of development of engineering, electronics was considered as an integral part of electrical engineering, but due to the advancements and developments during the last decades, electronics gained a rightful place in the field of engineering.
The major breakthrough in the field of electronics was achieved when semiconductor devices such as silicon and germanium are able for making electronic devices. In addition to these gallium arsenide technologies was also developed. The advantages of semiconductor devices are: The semiconductor devices are smaller, cheaper, and more reliable and they consume less power than vacuum or gaseous devices. The development of digital electronics (from 1946) gave a boost to the growth of electronics. In digital electronics there is not a continuous form of signals, instead it has only two possible levels: On or off state. These two possible states are typically represented by voltage levels.
The further development of electronics was possible only due to integrated chips (IC), in which a large number of devices are fabricated into a small silicon chip, usually known as integrated circuit. Now the number of devices on a chip passed over fifty million. The applications of electronics and communication are instrumentation, entertainment, general communication, medical electronics, computers, wireless communication, etc.
The future of our world looks exciting as the change is accelerating rapidly. Thus if we choose the new technologies, it will be better for our world and the way of living.
Now we are going to divide the components of electronics. The electronic components are broadly classified into passive and active components. The passive components are linear elements which control or modify the electronic circuit. The passive devices will not play an important role in the circuit’s performance. Without the help of active devices, it is impossible to design and implement electronic devices. The main passive components are resistors – energy dissipating devices, capacitors – energy storing devices, inductors and transformers.

Electricity is the flow of electrons in a conductor. The important measurements used for measuring electricity are voltage, current, resistance and power.

The first one is the voltage across a resistor. This term indicates the level of energy electrons relative to a reference point (i.e. ground in a circuit). If the voltage is high then, more energy electrons will travel through the circuit. If two points are at a different voltage levels with each other, then electricity will flow from one point to       other, if they are connected by some conductor. The unit of voltage is Volt (V). As sample of voltages at home are 110V, the AA, C & D cells we buy rated at 1.5V, and the Teleo Modules requires 5V.

The next one is current. This shows how much charge is travelling through the conductor per second. The unit of current is the Amperes (A). We can see that voltage and current are separate (different from each other) things: We will get a very small current at a very high voltage, a huge current at a very high voltage and so on.
The voltage and current is related by Ohm’s law:
Where’ v’ is the voltage, ‘I’ is the current and ’R’ is the resistance.

The next one is the resistance. Resistance (R) is an expression in which electron flow is impeded through a conductor. The unit is Ohm ( ). The resistance determines the relation between voltage and current (by ohm’s law). The amount of current is determined by the resistance, the conductor offers. If resistance is less then more current will flow. For a given power source of high enough capacity, if \we half the resistance, we will double the current. Conversely, if we double the resistance, then current will be half.

The last one is power. The unit of power is Watt (W). It is an expression of the overall energy consumed by a component. It is worked out by multiplying the voltage and the current together, P = VI. For example if a motor was running at 24V and the current drawing was 1.5A, the power dissipating would be 36W. (Electronics Basics)


There needs to be a path for electricity to flow, which connects all the elements together. 
The electricity will travel from the positive (+) side of the cell around the circuit to the negative side. This is called as the conventional current. The direction of electricity will be in the opposite direction of the flow of electrons.

In the given diagram, we can see how electricity travels from a cell around a loop through the lamp and back to the cell again.

Lamp and Cell Circuit
First figure refers to open circuit and second one refers to short circuit. The current will travel from one point to another only if a closed circuit is available.(Electronics Basics)

The flow of electrons: 

The direction of electricity: 

 Some symbols used to depict cells and lamps are,

Cell: This is also called as a battery, but technically a battery is multiple cells. The ordinary cell is rated at 1.5V.

Lamp: Lamps have voltage ratings like many things. The rating indicates the voltage that a lamp is designed to used. Lamps may also use their wattage - the power they consume. From this and we use the equation for power (I = P / V) the likely current consumed can be calculated.

Simple Lamp and Cell Circuit Diagram
This circuit diagram expresses only the essential features of the circuit. 
If battery is connected then the lamp will blows.(Electronics Basics)

More Electronic Components:

Resistor is the device that resists the flow of electricity The two important values associated with resistors are their resistance and their power rating. Resistance is measured in Ohms ( ).1kΩ is 1000 . The other value is power. Resistors dissipate energy so its important that at exactly how much energy they can dissipate is known. Read More.

Capacitor is the device that temporarily stores the electric charge. There are two main important values that characterize a capacitor. The first is the capacitance - measured in Farads, Micro-Farads ( F) or Pico-Farads (pF). The other quantity is the voltage (V). Read More.

Diode is the Semiconductor device that conducts electricity in only one direction.. Zener diodes permit conduction in the reverse direction only when the reverse voltage exceeds a certain value. TVS diodes are like Zener diodes except capable of much higher currents. A diode consists of a p-n junction. The combination of p and n type semiconductor will leads to the formation of p-n junction diode. Read More.

MOSFET. (metal-oxide silicon field-effect transistor). It mainly consists of source drain and gate. When the Gate (G) terminal voltage is sufficiently high, current will flow from the Drain (D) to the Source (S) terminal. the Gate voltage to be required is usually12V above the Source. MOSFETs are characterized by several values: their maximum voltage, their resistance and max power dissipation. 

Potentiometer is a variable resistor which Often connected as a Voltage-divider to create variable voltages when used as a rotational position sensor. 

LED is Light Emitting Diode. It Produces a lot of light for small current. But it will very quickly burn out if too much current is allowed to flow in it. A resistor in series with it to limit the current is usually the requirement.

Photoresistor is a resistor with the property that its resistance changes depending on how much light it receives. Photoresistors have a quite impressive resistance range(a few million ohms (M ) in the dark to a hundred ohms in bright light). One disadvantage is their reaction time is in the order of 100ms (too slow for many applications).

Supply. It saves having to draw a wire from the power source to every point in the circuit.

Ground. It is used to indicate that whatever is connected should be considered to be connected to the Ground of the power supply (it is the common point of a circuit).

Articles on Basic Electronics:

Passive Components:

1. Resistors - Specifications and Properties

2. Colour Coding of Resistors

3. Types of Resistors - Advantages and Disadvantages

4. Charging and Discharging of Capacitors

5. Capacitors - Classification, Applications and Properties

6. Specifications and Uses of Capacitors

7. Self and Mutual Inductance

8. Transformer Construction and Working Principle

Semiconductors, PN Junction Diodes, Different types of Diodes:

1. Semiconductors - Classification, Types, Band Theory

2. Intrinsic and Extrinsic Semiconductors

Sreejith Hrishikesan

Sreejith Hrishikesan is a ME post graduate and has been worked as an Assistant Professor in Electronics Department in KMP College of Engineering, Ernakulam. For Assignments and Projects, Whatsapp on 8289838099.

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