ArtsAutosBooksBusinessEducationEntertainmentFamilyFashionFoodGamesGenderHealthHolidaysHomeHubPagesPersonal FinancePetsPoliticsReligionSportsTechnologyTravel

Active Versus Passive Devices

Updated on July 15, 2011

Electronic components are classed into either being Passive devices or Active devices. Active devices are different from passive devices. These devices are capable of changing their operational performance, may deliver power to the circuit, and can perform interesting mathematical functions. While a device that does not require a source of energy for its operation.

What are Active Devices?

An active device is any type of circuit component with the ability to electrically control electron flow (electricity controlling electricity). In order for a circuit to be properly called electronic, it must contain at least one active device. Active devices include, but are not limited to, vacuum tubes, transistors, silicon-controlled rectifiers (SCRs), and TRIACs.

All active devices control the flow of electrons through them. Some active devices allow a voltage to control this current while other active devices allow another current to do the job. Devices utilizing a static voltage as the controlling signal are, not surprisingly, called voltage-controlled devices. Devices working on the principle of one current controlling another current are known as current-controlled devices. For the record, vacuum tubes are voltage-controlled devices while transistors are made as either voltage-controlled or current controlled types. The first type of transistor successfully demonstrated was a current-controlled device.

What are Passive Devices?

Components incapable of controlling current by means of another electrical signal are called passive devices. Resistors, capacitors, inductors, transformers, and even diodes are all considered passive devices.

Passive devices are the resistors, capacitors, and inductors required to build electronic hardware. They always have a gain less than one, thus they can not oscillate or amplify a signal. A combination of passive components can multiply a signal by values less than one, they can shift the phase of a signal, they can reject a signal because it is not made up of the correct frequencies, they can control complex circuits, but they can not multiply by more than one because they lack gain.

Diodes

Diodes are basically a one-way valve for electrical current. They let it flow in one direction (from positive to negative) and not in the other direction. Most diodes are similar in appearance to a resistor and will have a painted line on one end showing the direction or flow (white side is negative). If the negative side is on the negative end of the circuit, current will flow. If the negative is on the positive side of the circuit no current will flow. More on diodes in later sections.

Integrated Circuits

Integrated Circuits, or ICs, are complex circuits inside one simple package. Silicon and metals are used to simulate resistors, capacitors, transistors, etc. It is a space saving miracle. These components come in a wide variety of packages and sizes. You can tell them by their "monolithic shape" that has a ton of "pins" coming out of them. Their applications are as varied as their packages. It can be a simple timer, to a complex logic circuit, or even a microcontroller (microprocessor with a few added functions) with erasable memory built inside.

First Transistor

Transistors

A transistor is a semiconductor device, commonly used as an amplifier or an electrically controlled switch. The transistor is the fundamental building block of the circuitry in computers, cellular phones, and all other modern electronic devices.

Because of its fast response and accuracy, the transistor is used in a wide variety of digital and analog functions, including amplification, switching, voltage regulation, signal modulation, and oscillators. Transistors may be packaged individually or as part of an integrated circuit, some with over a billion transistors in a very small area - part of a trend of increasing transistor density known as Moore's Law.

Transistor stands for transit resistor, the temporary name, now permanent, that the inventors gave it. These semidconductors control the electrical current flowing between two terminals by applying voltage to a third terminal. You now have a minature switch, presenting either a freeway to electrons or a brick wall to them, depending on whether a signal voltage exists. Bulky mechanical relays that used to switch calls, like the crossbar shown above, could now be replaced with transistors. There's more.

Transistors amplify when built into a proper circuit. A weak signal can be boosted tremendously. Let's say you have ten watts flowing into one side of the transistor. Your current stops because silicon normally isn't a good conductor. You now introduce a signal into the middle of the transistor, say, at one watt. That changes the transistor's internal crystalline structure, causing the silicon to go from an insulator to a conductor. It now allows the larger current to go through, picking up your weak signal along the way, impressing it on the larger voltage. Your one watt signal is now a ten watt signal.

Transistors use the properties of semi-conductors, seemingly innocuous materials like geranium and now mostly silicon. Materials like silver and copper conduct electricity well. Rubber and porcelain conduct electricity poorly. The difference between electrical conductors and insulators is their molecular structure, the stuff that makes them up. Weight, size, or shape doesn't matter, it's how tightly the material holds on to its electrons, preventing them from freely flowing through its atoms.

Resistors

Capacitors

A capacitor is a passive electrical component that can store energy in the electric field between a pair of conductors (called "plates"). The process of storing energy in the capacitor is known as "charging", and involves electric charges of equal magnitude, but opposite polarity, building up on each plate. A capacitor's ability to store charge is measured by its capacitance, in units of farads.

Capacitors are often used by engineers in electric and electronic circuits as energy-storage devices. They can also be used to differentiate between high-frequency and low-frequency signals. This property makes them useful in electronic filters. Practical capacitors have series resistance, internal leakage of charge, series inductance and other non-ideal properties not found in a theoretical, ideal, capacitor.


A wide variety of capacitors have been invented, including small electrolytic capacitors used in electronic circuits, basic parallel-plate capacitors, mechanical variable capacitors, and the early Leyden jars, among numerous other types of capacitors.

Comments

    0 of 8192 characters used
    Post Comment

    • profile image

      Bill Souza 8 years ago

      I really like your website. It is very informative. I will come back and check out your upgrade.

      Bill

    • quicksand profile image

      quicksand 8 years ago

      I thought diodes were incorporated into integrated circuits, and were never used seperately in circuits as individual components.

    • guidebaba profile image

      guidebaba 8 years ago from India

      Nice Explanation aanaedwards.

    • kevinbernard31 profile image

      kevinbernard31 8 years ago from Oregon, USA

      Lot of information on basic electronics. Got refreshed my knowledge of electronics.

    • profile image

      ezekiel 7 years ago

      learn a lot of information, about this website..

    • profile image

      nivram 7 years ago

      diodes should be active devices right?

    • profile image

      snehal 7 years ago

      good information

    • profile image

      snehal 7 years ago

      good information

    • profile image

      snehal 7 years ago

      good information

    • profile image

      Mandeep 7 years ago

      Hi,

      Thanks for refreshing my knowledge about active and passive devices.

      The information is very helpful.

      Regards,

      Mandeep

    • profile image

      Sam 7 years ago

      Not clear

    • profile image

      AJISH 7 years ago

      VERY SIMPLE WORDS AND UNDERSTAND EASILY.THANKS FOR CREATION

    • profile image

      Niteen 7 years ago

      short but sweet....thanks

    • profile image

      raviteja 7 years ago

      a very good data collection

    • profile image

      krishnaveni 7 years ago

      thanks for u r answers

    • profile image

      Keerthana 7 years ago

      thanks for ur information

    • profile image

      Asif Nizamani 7 years ago

      Very useful informatio!

    • profile image

      Peter Enmore 7 years ago

      This is a great post, thanks for laying the info out clearly for everyone.

    • profile image

      raju 6 years ago

      Thanks your website is very helpful to me and my frieds,

      it include useful information in easy language.

    • profile image

      Abdoul Razak 6 years ago

      courrage votre informations nous aides

      ,,,,,,,,,,

    • profile image

      mandeep 6 years ago

      lc circuit can act as ossilator right???

    • profile image

      Captain  6 years ago

      It was use full. However many websites states that DIODE is an Active device.

      Confused.....!

    • profile image

      Amilcar Peres 6 years ago

      What is main reasonI cannot have two active devices in the same circuit?

      regards,

      Amílcar Peres

    • profile image

      nitin patel india 6 years ago

      ireally appreciate this web site.i can clear all my concept by thisone.thank you very much

    • profile image

      Khushwant 6 years ago

      Its amazing i got every point very clearly

    • profile image

      shahroz khowaja 6 years ago

      i am not satisfied

    • profile image

      daya 6 years ago

      thanks for information

    • profile image

      edmundo almachar 6 years ago

      explanation are very clear and interesting technically it is a great help for all doing intrumentation works

    • profile image

      rahul malode 6 years ago

      nice information about basic.

    • profile image

      ..... 6 years ago

      thanks for updating. i got lot of knowledge..

      best regards..

    • profile image

      warubna 6 years ago

      good

    • profile image

      Rabbia 6 years ago

      please give a detail explanation of active and passive circuit with video

    • profile image

      nikoy 6 years ago

      nice Info

    • profile image

      matheen 6 years ago

      diode is a passive device and it also a non linear device....diode have only forward direction so it is a nonlinear and diode have only a two terminals not there other external terminal(pin) by sending a vcc so is a passive ....resistor,capacitors and inductor are only a liner other devices allare non liner because of there are effecting a input signals..........before elements are not effecting it just changing voltage ans current value not signals ..........yes i got it

    • profile image

      ARUN KUMAR 6 years ago

      ITS VERY VERY INFORMATIVE.. THANKS....

    • profile image

      BILAWAL SAFFAR CHANNA 6 years ago

      NICE INFORMATON ABOUT ELECTRONIC INSTRUMENTS.AND ALSO NICE DIAGRAMS.GOOOOOOOOOOOOOOOOD.

    • profile image

      Ahmed hamisu 6 years ago

      Thanks for ur concise information on active and passive devices

    • profile image

      vinod 6 years ago

      nice theory

    • profile image

      nazim shah 6 years ago

      scr is the activwe componenet

    • profile image

      nihar ranjan behera 6 years ago

      good information , thank

    • profile image

      sajid Ali 6 years ago

      i want of all components detail.

    • profile image

      aulakh 6 years ago

      its informative .good.

    • profile image

      thirumala 5 years ago

      very good information

    • profile image

      Manjushree 5 years ago

      very gud information.

    • profile image

      dkmayo 5 years ago

      Good Hub, it is organized and explained well.

    • profile image

      samina soni 5 years ago

      Thanks for ur clear information.

    • profile image

      Amey 5 years ago

      got information when m in need

      thank you...

    • profile image

      Aryan 5 years ago

      sample,easy good. . . . .

    • profile image

      surbhi 5 years ago

      defination of active device &passive device must be in form of distingushed.

    • profile image

      SARWAN KUMAR 5 years ago

      Resistors also control the electron flow as they resist the electrons to limit the current to certain specific value though they are not called the active components. Explain why?

    • profile image

      SARWAN KUMAR 5 years ago

      diode is an active diode not the passive one because these can change the waveform of the signal and it the one of the definitions of active devices.

    • profile image

      SARWAN KUMAR 5 years ago

      u can have two active devices in single circuit.

    • profile image

      SARWAN KUMAR 5 years ago

      i mean to say more that u can have more than active devices in single circuit.

    • profile image

      ash 5 years ago

      i thought this whole electrical components were combined and put together in IC and would probably work independently bt i ws wrong it worked together forming chip

    • profile image

      swathi 5 years ago

      it is better to post the basic differenc between the element and device

    • profile image

      Nagabhushan 5 years ago

      Good information ,keep update,thank you

    • profile image

      Raihanul Islam 5 years ago

      thnx...

    • profile image

      Raihanul Islam 5 years ago

      thnx...

    • profile image

      manju 5 years ago

      it is very good information

    • profile image

      Goldi 5 years ago

      Thanks for giving information regarding active and passive component. Its very useful for me. Thanks again.

    • profile image

      jebidddasdddddddf 5 years ago

      yhdfhyfrtyhr

    • profile image

      More Monali U 5 years ago

      information in simple language

    • profile image

      virs6 5 years ago

      I'm confused about diode as a passive device as what you've stated above, while i've also read some information stating that diode is an active device.

    • profile image

      anjili 5 years ago

      nyc... so hlpful

    • profile image

      prasanjeet sarkar 5 years ago

      nice explanation with example

    • profile image

      Tladi 5 years ago

      that's a great componets 4 al ppl in de world nd most helpful 4 us

    • profile image

      arpit 5 years ago

      short and sweet. good described..

      but diode active or passive new confusion arises.....

    • profile image

      rp srivas 5 years ago

      good decribed satisfied

    • profile image

      Tanimowo 5 years ago

      Transit resistor still remain its name.

      Diode is explain as clear as itself.

      many others helps research work.

      GOOD INFORMATION.

    • profile image

      TANIMU SULEIMAN 5 years ago

      THANKS YOU FOR PROVIDED US WITH GOOD INFORMATIONS

    • profile image

      Sophie 5 years ago

      I am Sophie ma from Hqton Circuit Technology Co., Ltd., which is a professional manufacturer focusing on PCB.( Focus on sample, small-medium volume manufacturing.There is No Minimum Order Quantity Restriction;)

      Tel:(+86)13512741175

      Fax:(+86)752 5311376

      Foxmail?sophie@hqtonpcb.com

    • profile image

      Guddidea 5 years ago

      Thank You this really helped. Someone shoul explain how to install or insert a diode correctly.

    • louromano profile image

      louromano 5 years ago

      Great hub ! Thanks your website is very helpful to me.

    • profile image

      anjum 5 years ago

      tooooooo gooooooooooooooooooooooood

    • profile image

      Ron 5 years ago

      I really like your hub, thank you for putting it up .

      Ron from the http://www.intervalstraining.net

    • profile image

      Sushant 4 years ago

      Very informative website

    • profile image

      sherpa 4 years ago

      its short bt nice...

    • profile image

      aminul,R/F 4 years ago

      very very good explaination with example.thaks to all.

    • profile image

      Fortunatus J swalala 4 years ago

      thank you for your explanations and examples on active and passive devices

    • profile image

      AMIR 4 years ago

      VERY GOOD...WELL DONE

    • profile image

      riyaz 4 years ago

      what are the 555timers application?

    • profile image

      jonny bairstow 4 years ago

      amazin....

    • profile image

      veena 4 years ago

      need more explanation on applications of all active and passive devices in ckt

    • profile image

      shoaib 4 years ago

      nice

    • profile image

      carlo_19 4 years ago

      tnxs

    • profile image

      lorraine kwanisai 4 years ago

      thank you explanation on passive and active components.waaaaaaal

    • profile image

      lorraine kwanisai 4 years ago

      thank you explanation on passive and active components.waaaaaaal

    • profile image

      Anadirunika 4 years ago

      10 Одноцветный блок. Если вы хотите закончить работу побыстрее, подыщите такой рисунок, в котором предусмотрено использование небольшого числа оттенков нитей или множество сплошных участков, выполненных одним цветом. Это сокращает необходимость частой смены цвета ниток. Выполняя подобный дизайн, экономишь действительно много времени.

    • profile image

      santosh mandi 4 years ago

      very good information

    • profile image

      KagoVegreence 4 years ago

      My partner and i employed to acquire high on life however of late I've piled up some sort of weight.

    • profile image

      Futamarka 3 years ago

      Развитие жанра. Первым альбомом хард-рока принято считать дебютную пластинку группы Led Zeppelin 1969 года. Именно на этом альбоме группа окончательно вышла за рамки тяжёлого блюза и вывела подобную музыку на принципиально новый уровень. Для Led Zeppelin был характерен крайне высокий уровень исполнительского мастерства: виртуозные гитара и бас, мощные ударные, драматический вокал. В дальнейшем Led Zeppelin нередко экспериментировали, вводя в свою музыку элементы фолка, классической музыки, регги, фанка.

    • profile image

      Jaison007 3 years ago

      thanks to whom given this opportunity

    • profile image

      jay 3 years ago

      thank you

    • profile image

      sudarshan jain 3 years ago

      very good information

    • profile image

      Cealtyacula 3 years ago

      Hey guys just wanted to tell you all about my new blog, its all about how to make money fast, so if you have 2 minuites have a quick read and tell me what you think. helpful hints

    • profile image

      eng Abdulaziz 2 years ago

      Thank you for providing such a helpul material. I read what I want know in simple English and understandable.

    Click to Rate This Article