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Identifying Electronic Components

NumberedBoardHow-to identify and locate information for electronics components you can recycle from discarded gadgets. Brandon gives us example pictures and descriptions for most types of electronics components to help you stock up your home electronics lab. This is a must read for new electronics hobbyist.

This article was submitted by Brandon Uhlig as part of the β€œHobby parts for articles ” program. Brandon receives a Modern Device Company Bare Bones Arduino Kit for this fantastic article. Let Brandon know that you appreciate articles such as this by posting a comment. I hope to see many more articles like this one here at uC Hobby.

Scrounging for parts is a great way for hobbyists to save some money. You can get tons of parts out of discarded or unused electronics. But how do you identify all those parts? This article will give you some ideas on where to start.

The focus will be on common reusable through-hole components hobbyists will be most likely to scrounge and re-use.

Obviously, this is by no means a complete list, there are way to many different electronic components to put into a quick guide, but maybe this will give you some ideas to narrow down your search on an elusive component.


Resistors are one of the most used components in a circuit. Most are color coded, but some have their value in Ohms and their tolerance printed on them. To identify values, you can check out the Electronic Assistant software found in the Free Electronics Hobby Software article here on uC Hobby, or find one of the many online tools. A few of them can be found at in the Calculators section. A multimeter that can check resistance can also be helpful, providing the resistor is already removed from the board (measuring it while still soldered in can give inaccurate results, due to connections with the rest of the circuit). They are typically marked with an “R” on a circuit board.


Potentiometers are variable resistors. They normally have their value marked on them, normally marked with the maximum value in Ohms. Smaller trimpots may use a 3-digit code where the first 2 digits are significant, and the 3rd is the multiplier (basically the number of 0’s after the first 2 digits). For example, code 104 = 10 followed by four 0’s = 100000 Ohms = 100K Ohms. They may also have a letter code on them indicating the taper (which is how resistance changes in relation to how far the potentiometer is turned). They are typically marked with an “VR” on a circuit board.


Capacitors are also very commonly used. A lot have their values printed on them, some are marked with 3-digit codes, and a few are color coded. The same resources listed above for resistors can also help you identify capacitor values. They are typically marked with an “C” on a circuit board.


Inductors, also called coils, can be a bit harder to figure out their values. If they are color coded, the resources listed for resistors can help, otherwise a good meter that can measure inductance will be needed. They are typically marked with an “L” on a circuit board.

Crystals Oscillators

Crystals and Oscillators are also fairly easy to identify by sight. Most are clearly marked with their operating frequency printed on them. They are typically marked with an “X” or a “Y” on a circuit board.


Relays are typically enclosed in plastic, and many have their specs printed on them. They are typically marked with an “K” on a circuit board.


Transformers are normally pretty easy to identify by sight, and many have their specs printed on them. They are typically marked with an “T” on a circuit board.


Batteries are also pretty easy to identify, and are well marked with their specs.


Fuses can be easy to identify, and typically have their voltage and amperage rating marked on them.


Semiconductors, such as Diodes (typically marked with an “D” on a circuit board).


Transistors (typically marked with an “Q” on a circuit board),


Bridge Rectifiers (typically marked with an “BR” on a circuit board)


Integrated Circuits (typically marked with an “U” or “IC” on a circuit board), can take a little more work to figure out what they are. Many different types can use the same packaging, so they all can’t be identified by just their looks. In most cases the information you need is found in the device’s datasheet. The datasheet is a document containing the specs on the device and many will include example circuits, links to app notes, and other valuable information. They are typically in a .PDF format. If you have never used a PDF file before, you will need a PDF reader to open it. A couple of free ones can be found below. (Adobe Reader) (Foxit Reader)

To find a datasheet, you first need to find some info on the part. Luckily, they have part numbers which can be used to help identify them. They may also have the manufacturers logo on them. Finding the manufacturer can be extremely useful as the most up-to-date information is usually available on their website. For help in finding the manufacturer based on their logo, check out the following sites. They also include links to the manufacturer’s websites. Datasheets can normally be found under the support/download section, or you can put the part number in their search bar.

If you can’t find any information on the manufacturer, or are unable to find a datasheet on their website, you do have a few more options. There are several search engines on the web to help locate datasheets. Some free ones are listed below. You can search by part number, or even by a partial part number.

If those fail, you can try using a search engine such as google. Adding “pdf” to your search string can slim down the results, reducing the amount of sites just selling the part with no other useful information. There is also a chance of finding no information on a particular part. Some manufacturers will produce special order parts with “house” numbers, which can mean nothing except to the company that actually purchased them.

There are also many other components you may want to scrounge off a board, but may be difficult to find specific information on. They may not be marked, but you can find some good general information on the web to help you out.




And now for a little test πŸ™‚ See how many components you can identify on the following board. Answers can be found by scrolling below the board – No cheating!



1 Diodes
2 Piezo Buzzer
3 Transistor
4 Transformer
5 Relay
6 Inductors
7 Integrated Circuits (IC’s)
8 Capacitors
9 Crystal
10 Resistors

Posted in Development Tools, Discovering, Electronics Links, Scrounging, Scrounging Parts.

42 Responses

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  1. Sajiv says

    Nice articles

  2. Binu says

    Nice informations on a single page.

  3. Frenoy says

    hey nice info for a beginner like me,but it wud b advisable to add info about testing them in this or other articles….

    (if such an article exists,do let me know about it..)

  4. Binu says

    Nice Informations πŸ™‚

  5. bala subrahmanyam says

    I have retired from govt. service and started for a hobby electronics which I am dreamful in college days.There was no network in those days The information has been a good source for a beginner like me.I thank u and will be seeking u r advice for sites of this nature

  6. BjΓΈrn Keizer says

    Thanks for the information, I never thought of using the components before, untill I heard about your website by someone from instructables.

    Keep up the good work!

  7. Mathew Phiri says

    I like the information. it is quite beneficial and educative

  8. sachin says


  9. tarzan says


  10. nitin says

    please tell me the functions and working process of electronic components

  11. abrar shah says

    very good site for new hobbiest

  12. russ_hensel says

    For more salvage info see:

  13. dfowler says


    Good question, I dont know where you would go for that information. My guess is that there is very little precious metal but I don’t know.

  14. Kevin says

    Im trying to find a site that educates on how to find out how much precious metals are in a ic chip. How much gold, silver, etc. are in the chips is what im after. I didnt see it on the data sheets. Any help?

  15. Rajesh J. Patel says

    This is a very good demonstration for a layman working with
    electronic circuit board, as a havent’ ever seen before

  16. RoseMary says

    “DSP Innovations has recently launched a FREE data sheet search site. The site, , enables component and design engineers to easily find electronic and
    semiconductor datasheets necessary for their projects. Please try out the service and provide your feedback to support -at- datasheetpro [dot] com.”

  17. Catherine says

    “DSP Innovations has recently launched a FREE data sheet search site. The site,, enables component and design engineers to easily find electronic and
    semiconductor datasheets necessary for their projects. Please try out the service and provide your feedback to support -at- datasheetpro [dot] com.”

  18. prathap kumar says

    will you please display thermal fuse pictures

  19. prathap kumar says

    Excellant educative material

    prathap kumar

  20. Jeff says

    This website will help you find the latest datasheet fast. Search it and you will see the links for a datasheet usually go directly to the manufacturer. They aren’t out of date copies. for component datasheets.

  21. Rashid says

    Thats Good. Pics are clear and good

  22. dfowler says


    Sounds like you need a current source. Look at this article for a posible solution.

  23. baw says

    I need a simple circuit that gives me a variable control over available current (mA) output but maintains constant voltage from 4 AA batteries (6V). Any thoughts on where I can find this out please let me know. Thanks.

  24. Nathan says

    Great all around article! This is very informative for those who don’t know anything about integrated circuits or components…

    Post your capacitor, inductor, resistor,IC component requirements on an auction, distributors will bid and compete with each other to win your purchase order!

  25. abbas1707 says

    nice tutorial

  26. jh liton says

    yes, i think i got the site what i am looking for a long time. thanks liton

  27. Ajay Bhargav says

    great informative article.. linked to me πŸ™‚

  28. khubilai says

    excellent… now i can start disecting all my electronics before i through them away. and have an idea of what i’m keeping.
    good job for beginners like me.

  29. Neeraj says

    Fotos are very good. But absent of chip type (S.M.D.)component is not good. Please give S.M.D.(chip type) component foto for identify. Because in thiese days most of manufacturer use this type of component. thanks

  30. BrandonU says

    Thanks for the great comments. I’ve been thinking of working on another that goes a bit more in-depth, especially on some of the more common semiconductors you would be most likely to reuse ( including bridge rectifiers πŸ™‚ ). Based on the feedback, It looks like it would be well received. I like the idea of breaking it into series, because it could become quite lengthy otherwise. Maybe some other people would have a component they would like to do an article on. Maybe a list of things to cover and you can choose a topic to write on? Just an idea…
    As far as removing components, there is a good article on this site on using a heat gun. Just be sure to follow the safety precautions. Solder suckers and solder wick also work well. Both are probably stocked at your local Radio Shack or other local electronics part store. Another trick I have used for multi-pin parts is to put one big glob of molten solder over all the pins, then pull it out. Just be careful not to jerk on the part or bump the board around and sent the molten solder flying everywhere!

  31. James says

    A solder sucker is really good for removing the solder. Heating the solder while pulling the components is tricky. It becomes very difficult when there are more leads on a component. Best to remove the solder. There is also another product used for removing solder called solder wick.

    Best of all have fun salvaging!

  32. John says

    how many memories of highschool this brings back.

  33. Epimortum says

    I’m pretty much a noob to electronic components and have a question.

    How do you removed them?

    The only reasonable way I can tell is take a soldering Iron and reheat the soder on the back of the board and pull the components off.

    Not a problem if that’s what you do, just curious.

    Thanks for the fantastic article.

  34. Timo says

    Very much appreciated. I’ve been looking for something like this. Now if I only knew what to do with them… πŸ™‚

  35. dfowler says

    Good point. Maybe we could do a series of articles explaining each component, it’s symbol, the common packages, product marking codes and how they are used. The latter being a very basic run down with lots of links to existing sites with detailed information.

  36. Newaz says

    Something essential for hobbyists or new comers in electronics. Good job done.

  37. xSmurf says

    Hiro: I agree but they vary a lot from one manufacturer to another except maybe for date stamps.

    Nice write up πŸ™‚ Would have been nice to add the circuits diagram for each part. Maybe a little definition too, not everyone knows what a “Bridge Rectifiers” is and what it does.

  38. dev says

    great all round article. thanks πŸ™‚

  39. Hiro Protagonist says

    I think a useful addition to the IC section would be some info on how to figure out the part number from the manufacturer ID, date code, speed and power rating and other verbiage that’s often marked on them.

  40. Evil Paul says

    Nice article and a good sign for the articles to come. The Aussie magazine Silicon Chip has a great series of articles on salvaging components and what you can do with them. The slogan is for the series is “Rat It Before You Chuck It!”

  41. dfowler says

    The comment above is a trackback I believe but the link does not work for me.

Continuing the Discussion

  1. Β΅[micro]electronics info linked to this post on July 15, 2007

    The Beginners Basics: How to identify Electronic Components

    Have a look at the article Identifying Electronic Components on the . There is almost complete guide to identifying components found on older PCBs or discarded electronics you can recycle and use.