Basic Electronic components - Their features & applications

In this article I will be providing an insight into the basic electronic components like resistors, transistors, diodes etc that form the backbone of any electronic circuit system.

In this article, we will be discussing about some common electronic components that are frequently used in designing complex systems. The understanding of these hardware components would help you identify and comprehend their properties and build larger systems using these as the fundamental blocks. So here we go....


The most common element often encountered is a resistor. Commonly used resistors are carbon composition resistors. According to me it is the cheapest component we use in our circuits and it is used to limit the flow of current in various electronic devices. We can judge the value of a resistor using a standard colour coding scheme. Each resistor has 4 colour bands:
  • 1st and 2nd band forms a number
  • 3rd band is a multiplier
  • 4th band tells us about the tolerance
A resistor costs just 20 paisa (INR) per unit, you will get a bunch of 5 resistances in 1 Re. They are generally available in many variants ranging from few ohms to mega ohms.


Next comes the diode which is a two-terminal device with very low (ideally zero) resistance to current flow in one direction and high (ideally infinite) resistance in the other. This leads to asymmetric transfer characteristics which differentiates it from a resistor. A diode won't cost more than a rupee. It is mostly used in rectifier circuits for converting AC to DC. The most commonly used diode is 4007. Please note that numbers of all the electronic components are very important since you cannot buy components from a shop unless and until you know the correct number of a component.


L.E.D (Light Emitting Diode) is one such type of diode which gives an optical power output as current is injected into it. They are used as display/tester devices in many circuits. LED's are available in many variants such as high intensity LED, tri-coloured LED, infra red LED etc. Depending on the wavelength of light required in a particular application, we can choose the correct LED required for our purpose.


Now we will talk about Transistors, which is the most important 3-terminal device. The three terminals are called: Emitter, Base and Collector (in case of a bipolar junction transistor) and Source, Gate and Drain (in case of a MOSFET). BC547 and BC557 are commonly used BJT's (costs around INR 5) The prominent significance of a BJT is that it can either be used as a switch (turning on or off and behaving as a short/open circuit) or as an amplifier depending on what we want our circuit to do. We can control the mode of operation by controlling the amount of current flowing through the base. Below a certain minimum threshold the device will be off and as you increase the current, it would turn on and amplify the input signal.


Capacitors are the important charge storage elements used commonly. They find applications in many circuits like filters, rectifiers, amplifiers etc. Capacitance is generally specified in micro farads. They are of two types:
  • Electrolytic Capacitor (Rs. 2-5)
  • Ceramic Capacitor (Rs. 0.5-1)

Now we will move to some non electronic components that help us in designing circuits.

Connectors of different types are used to provide a link between all of the electronic components discussed above. They provide a strong, easy and reliable connection between various circuits. In most of the connectors, the portion with the wire is called the female part while the head is called the male part. They are available in different variants (from 2 pin to 8 pin)

Breadboard provides a solid platform for testing our circuits. Components can be directly inserted into the holes and can be used to make circuits for testing. Advantage of using a breadboard in comparison to P.C.B (Printed Circuit Board) is that components can be reused and can easily be repaired. The cost of a normal breadboard is between Rs. 55-60. If we need a permanent connection then we prefer using a general purpose P.C.B. Components are placed on the other side of a P.C.B and their metallic legs can be soldered on the copper side. Then you have to line solder between holes to conduct current from one point to other. Circuits on a P.C.B look much neater as compared to that on a breadboard.

So this pretty much covers all the basic electronic components which you will be using in all the circuits that you build. This brief introduction would help you in selecting a particular component based on the specifications of your circuit. I would suggest you to play with them and get a hands on experience before you start building complex circuits.

In the next article we will be discussing about Power sources, Sensors and Actuator modules.

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Author: Timmappa Kamat13 Mar 2015 Member Level: Gold   Points : 0

So you have covered almost all important "building blocks" of an electronic device. That should even serve as a practical guide to the students of electronics. Devoid of any technical jargon normally found in the textbooks, this article explains the minute details.

Guest Author: Sunitha25 Mar 2015

Now days, advancement in this basic components are invented for comfortable use of all the devices.

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