Some electronic components I purchased are smaller than expected. - Page 1
Forum section: electronics / beginners

author: cvriv
author_rank: Frequent Contributor
timestamp: June 28, 2016, 02:43:04 am
content: I bought some capacitors and they are very tiny. I also bought some transistors, 2N3904 If I remember correctly, and they are a lot smaller than I was expecting. It's not entirely a bad thing, but might be troublesome maybe when using them on a breadboard? I used these transistors in class and they were bigger. How do I know what their actually size is prior to purchasing?

author: RobertHolcombe
author_rank: Frequent Contributor
timestamp: June 28, 2016, 03:00:45 am
content: Depends where you buy them from, but most online stores will either provide component specifications and/or datasheet which will contain the physical dimensions of the component package, pin pitch etc.

author: helius
author_rank: Super Contributor
timestamp: June 28, 2016, 03:02:00 am
content: Check the "package" or "outline" field in the part description, and cross-reference to the mechanical drawing for that outline from the manufacturer. For instance, a 2N3904 is sold in TO-92 package, a thru-hole (when used as designed) package about 5mm square.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: June 28, 2016, 03:14:12 am
content: What did you purchase?2N3904 is a JEDEC designation, where the spec includes the package, and limits on the electrical characteristics. Manufacturers usually provide additional data (typical data, tighter ranges, graphs) as well.If what you got is anything but a normal body TO-92, you didn't buy a 2N3904.There's no such thing as an "SMT 2N3904" for instance, but there does happen to be the widely available MMBT3904 with identical electrical characteristics. Some other popular numbers may be repeated in this way (MPSH10 / MMBTH10, TIP31C / MJD31C, etc.), but it's not a system, and coincidences abound.Not that it's a big deal, as there are a hundred kinds of general purpose transistor with largely overlapping specs (from the ancient 2N2222 to '3904, 2N5088, 2SC1815, BC847, etc...), and the main thing you're buying is package and pinout.Tim

author: ez24
author_rank: Super Contributor
timestamp: June 28, 2016, 03:20:22 am
content: Quote from: cvriv on June 28, 2016, 02:43:04 amI bet you ordered from eBay, Aliexpress, or Amazon. I did the same thing.

author: bitseeker
author_rank: Super Contributor
timestamp: June 28, 2016, 04:13:00 am
content: Electronics suppliers such as Mouser, DigiKey, etc. provide datasheets for components. These typically include a mechanical drawing of the part with lots of dimensions.

author: joseph nicholas
author_rank: Frequent Contributor
timestamp: June 28, 2016, 03:05:07 pm
content: Here´s an example, I ordered these and they were a lot smaller than 0805. No response to my complaintshttp://www.aliexpress.com/item/100PC-Lot-0805-SMD-LED-light-Package-LED-Package-Red-White-Green-Blue-Yellow-0805-led/32513628361.html?spm=2114.13010608.0.100.Bg7Iru

author: Audioguru
author_rank: Super Contributor
timestamp: June 28, 2016, 03:31:57 pm
content: They are trying to sell "sweepings from the floor" of a Chinese manufacturer and they do not know what they are. Most of them might not work.

author: wraper
author_rank: Unknown
timestamp: June 28, 2016, 04:33:09 pm
content: Quote from: joseph nicholas on June 28, 2016, 03:05:07 pmSeem to be 0805 on the picture. Did you measure actual dimensions? Don't forget that 0805 is substrate size, not actual encapsulated led in the middle. Next size is 0603 and they are tiny compared to 0805, not just "a lot smaller".

author: cvriv
author_rank: Frequent Contributor
timestamp: June 28, 2016, 09:15:47 pm
content: Sorry for the late reply. Yes I did by them from Amazon. Lol. Guess I learned my first lesson. The NPN transistors I got did say TO-92.These are the ceramic capacitors I bought.https://www.amazon.com/gp/aw/d/B01GCIFS0K/ref=yo_ii_img?ie=UTF8&psc=1I guess i'll only buy from mouser or digikey them.

author: bitseeker
author_rank: Super Contributor
timestamp: June 28, 2016, 09:22:46 pm
content: Quote from: cvriv on June 28, 2016, 09:15:47 pmIt depends if you need specific dimensions, characteristics, provenance, etc. As with most things, if specifics are important, get it from a reputable source. If it's just tinkering, other places may be just fine. For example, I buy a lot of components from Mouser and DigiKey when I repair or refurbish equipment because I want the spacing and characteristics to be right.