## How to Understand Electronic Components

written by: Swagatam • edited by: Lamar Stonecypher • updated: 10/12/2011

The sections of this guide provide links to many articles that explain some of the important electronic components commonly used in all types of electronic circuits. Important parts like resistors, capacitors, transistors, and ICs are all explained here.

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In one of the previous articles regarding How to Identify Electronic Components we've already studied the practical verification process of various electronic components. However along with external identification, studying the internal specification of individual electronic components also becomes important for better recognition and understanding of these devices.

The following sections are filled with linked articles explaining the various important passive and active electronic components normally used in most electronic circuits.

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### Explaining Resistors

Although active components might look like they dominate electronic circuits, without appropriate current control parameters even the most sophisticated electronic system can become completely helpless and unable to function. Resistors act as current limiters, or rather controllers, and allow only the required amount of power to go into the various active components, thus allowing a safe functioning of the unit. These parts are the most elementary with their designs, yet perform the monstrous task of correctly configuring the basic structure of an electronic circuit.

No matter how simple resistors may appear to be, they too require critical calculation while being introduced into their relevant positions in a circuit. The distinguishable color bands over a typical resistor are in fact the codes written over them which must be read through special tables.

The following articles present a complete tutorial for resistors, starting with a broad overview regarding their basic functioning to more complex details about the reading of their color codes and also calculating them in groups while configuring circuits using them.

What is the Function of a Resistor?

How to Measure Resistance Using a Multimeter

How to Identify Resistors Through Their Color Codes

How to Measure Resistors in Series and Parallel

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### Explaining Variable Resistors

The above explanation discussed resistor in their fixed forms, which meant that the parts could be introduced with a certain fixed values and the corresponding fixed current and voltage levels could be passed.

However in many applications the voltage and current levels in a circuit are required to be set in response to some external parameter. During such occasions variable resistors become very handy and many are made specifically for such applications.

These are also called potentiometer and presets. Potentiometers are the ones which are bigger in size, incorporate knobs, and are normally kept protruding externally over a circuit enclosure so that the necessary adjustments can be done whenever required by the user (e.g. a dimmer switch or volume control).

Presets are rather smaller in appearance, are required to be soldered over the PCB, and are normally used for prior fixed settings through a screwdriver.

Other forms include variable resistors which change their physical characteristic with the change in the ambient levels of heat or light.

All the above forms of variable resistors are rigorously explained below through examples:

How do Potentiometers Work?

What are Potentiometer Transducers?

How to Identify a Potentiometer

What are the Types of Potentiometers?

How do Thermistors Work?

What is a Thermocouple?

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### Understanding Capacitors

In electronic circuits resistors may be used for controlling voltage and current levels, but capacitors fall under an entirely different category of the passive components. They perform the functions of storing and releasing voltages and currents by the process of charging and discharging.

Their purpose helps to induce timing or time periods in a circuit. The timing is extensively used in oscillator circuits and timer circuits. All sophisticated electronics like microcontrollers require oscillators, making capacitors one of the most important components with them.

Among other applications capacitors also perform important functions like filtration of AC, blocking of DC, and introducing the property of reactance, which is used for many different electronic circuit applications.

The following article links takes you deeper into the world of capacitors:

What are Capacitors?

How do Capacitors Function

How to Make a Capacitance Meter

How to Calculate Reactance of a Capacitor

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### What are Rectifier Diodes?

All semiconductor components come under the active component family, and diodes are the most fundamental of them. However diodes just like resistors (for the passive family) are one of the most important parts in the active electronic parts family. The fact that AC cannot be turned to DC without using diodes itself speaks volumes regarding these tiny semiconductors. Diodes are also attributed with the property of blocking DC, or rather allowing DC only from its anode to cathode, and vice versa.

More about these outstanding components is discussed through the links given below:

How Rectifier Diodes Function

How to Build a Bridge Rectifier

How to Calculate Rectifier Efficiency

What are Zener Diodes?

How to Control Current Through Zener Diodes

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### How Transistors Amplify

The big brothers of diodes, transistors though they have identical internal configuration like diodes, are entirely different with regard to their operations. Basically these semiconductor active parts are three-legged and better known for their properties of signal amplification. The amplified signal can be DC or AC. These components are truly flexible with their specs and there's no doubt why transistors are considered to be the backbones of modern electronics. Amplification is not the only feat that transistors are capable of doing; they are also extensively configured as comparators, drivers, voltage doublers, etc.

The following articles present a detailed study regarding transistors in their all different forms:

How Transistors Work

How the 2N3055 Device Works

What is hFE in a Transistor?

What is Common Emitter Configuration in Transistors?

How to Understand the Small Signal Transistor

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### Learning to Use LEDs

LEDs, or light emitting diodes, have similar technical identification to rectifier diodes, however they are made and meant entirely for different reasons. These active components have the amazing ability of emitting light under the influence of current. The lights may be of many different colors depending upon their individual specifications. Development in LED technology has presented a whole range to select from. The applications of LEDs vary from decorating toys, homes, and monitor lights to the more sophisticated areas of LED tubelights.

Everything about LEDs and their application parameters are discussed in the following linked articles:

How LEDs Work

How to Check LEDs

How to Determine Safe LED Current

How to Calculate LEDs in Series and Parallel

How to Wire LEDs

What are the Main Features of LEDs?

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### Understanding ICs and Their Internal Composition

ICs or integrated circuits, as the name refers to, are complex miniature circuits integrated together in one package for enforcing certain interesting and relatively complex implementations. These are basically made up of many (in millions) complex networks of resistors, capacitors and transistors embedded inside a tiny space with the relevant pin-outs arranged in a row. The pin-outs are identified through their specific datasheets.

The links presented below explain a few of the important ICs and their pin number assignments.

What are ICs

How Logic Circuits Work

How to Understand 8085 Pin-Outs

How to Understand the Pin-Outs of IC 4013

How to Understand IC 4017 Pin-Outs

How to Understand IC 4060 Pin-Outs

How to Understand IC 317 Pin-Outs

How to Understand IC 74LS164 Pin-Outs

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### Relay Working Principle Explained

The above parts are entitled specifically for implementing typical electronic circuits, but the application would be incomplete if many of the specific circuits are unable to handle or operate high voltage and powerful loads. A relay comes to the scene when an output stage comprising a transistor is required to operate loads beyond its limitations. The relay, as the name suggests, "relays" the transistor command through its switching contacts to operate high voltage and current loads like our domestic mains appliances, etc.

How Relays Work

How to Wire a Relay

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### SCRs and Triacs Explored

Another important member of the electronic active component family are the thyristors and Triacs. The basic applications of these components are similar to the above explained relays, yet they differ a lot with their practical operating principles. Thyristors or SCRs or triacs do not incorporate isolated contacts like relays and rather have common ground lines, merging the DC and the high voltage AC lines together, a negative point which makes circuits involving them dangerous to touch in uncovered positions. However these components, being free from moving contacts, are more reliable, quicker, and do not degrade with passing time.

How Thyristors Work

How to Use Thyristors

How Triacs are Used in Solid State Relays

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### Understanding and Designing Transformers

No electronic system can work without their specified power inputs. Though power may be easily available through our mains AC outlets, the magnitudes are just not suitable for vulnerable electronic circuits; they are just too strong for them to work safely.

Transformers are designed for stepping down mains AC levels to lower magnitudes that can be safely used with circuits consisting of the above discussed parts.

The links below provide all the necessary details involved with electrical transformers:

How Transformers Function

How to Design a Transformer

How to Use a Transformer

How to Understand Transformers Comprehensively

How to Make a Homemade Variac