Please help me identify this component - Page 1
Forum section: electronics / beginners

author: barnsleylad
author_rank: Newbie
timestamp: October 16, 2014, 09:24:55 pm
content: Hi,This is my 1st post on this forum, so first thing I'd like to do is say Hi :-)I'm relatively new to electronics and I'm trying to build a cable to link my Bang and Olufsen Beomaster amp to my computer so I can control iTunes with the B&O remote.I have all the relevant information (I think) and I'm currently trying to source components, but I've come un-stuck..I know its a transistor but I don't know where to find the right one... google doesn't seem to help.It has the following markings on it - on the top line it says C547B and below that W 39. I have attached a photo.Can anyone tell me where I can find this component?Kindest regards,Lee

author: Tandy
author_rank: Frequent Contributor
timestamp: October 16, 2014, 09:27:28 pm
content: It is probably a BC547B NPN Transistor.

author: Andy Watson
author_rank: Super Contributor
timestamp: October 16, 2014, 09:31:51 pm
content: It's a low power NPN transistor. Try prefixing the number with 2S, i.e. 2SC547B. Almost any low power NPN would fit.

author: Richard Crowley
author_rank: Super Contributor
timestamp: October 16, 2014, 09:39:54 pm
content: While there is a possibility that it might be a 2SC547B, the photographic evidence online much more strongly suggests that it is a BC547B.IME, it is rather rare for Asian number transistors (2S...) to be reverse-printed like that. It is much more common in European transistors (BC....)And there are photos online that show BC547B that look identical to yours except for the date-code (the second line).We might even be able to suggest sources if you had completed your user profile to at least reveal what country you are in??But, as Mr. Watson said, probably most any random NPN small-signal transistor would work in that non-critical application.

author: grumpydoc
author_rank: Super Contributor
timestamp: October 16, 2014, 09:45:08 pm
content: QuoteThe username would suggest a small (ex) mining town in South Yorkshire, UK - not too far from where I grew up as it happens.For all its problems as a supplier of components ebay might be as good a source of BC547B's in small quantities. I can't imagine anyone would bother faking them.Or a small supplier such as Hobbytronics, although they don't actually stock 547's they have BC548's which would do just as well.

author: Tandy
author_rank: Frequent Contributor
timestamp: October 16, 2014, 09:47:49 pm
content: At the risk of sounding like advertising I know where to find them for 9p each

author: grumpydoc
author_rank: Super Contributor
timestamp: October 16, 2014, 09:51:58 pm
content: QuoteTandy always were expensiveEDIT: That is better than 46p each at Maplin's though.

author: Andy Watson
author_rank: Super Contributor
timestamp: October 16, 2014, 09:52:47 pm
content: Quote from: Richard Crowley on October 16, 2014, 09:39:54 pmReally ?http://ehservice.ca/parts/index.php?route=product/product&product_id=2878Though a BC547 would probably be equally as good. If it's the "barnsley" as in South Yorkshire, I reckon Maplin would be a reasonable source (on a good day, with the wind blowing in the right direction.)

author: barnsleylad
author_rank: Newbie
timestamp: October 16, 2014, 09:54:44 pm
content: Thanks for all the reply's.I've updated my profile with my location (Newcastle) I was born in Barnsley (the little ex-mining town).I really think I am out of my depth to be honest, the last time I tried to solder was a disaster, the solder just wouldn't stick no matter how much I cleaned the wires with IPA so I'm probably going to need lots of advice and help.I'll attach a drawing and a few pictures of what I am trying to build.If anyone is willing to put one together for me, I'll happily pay what ever it costs.Thanks again,Lee

author: brillopad
author_rank: Contributor
timestamp: October 16, 2014, 09:58:14 pm
content: Amazon UKhttp://www.amazon.co.uk/100pcs-BC547-TO-92-NPN-Transistor/dp/B00CYYMPN0/ref=sr_1_1?ie=UTF8&qid=1413496538&sr=8-1&keywords=bc547100 for £1.80 free shipping

author: Richard Crowley
author_rank: Super Contributor
timestamp: October 16, 2014, 09:58:31 pm
content: Quote from: Andy Watson on October 16, 2014, 09:52:47 pmThe photo you cited is far more authoritative than the speculative ones I was looking at. Thanks.Apparently its just by accident that I've never seen a 2SC transistor reverse-printed like that.

author: Richard Crowley
author_rank: Super Contributor
timestamp: October 16, 2014, 09:59:55 pm
content: Quote from: brillopad on October 16, 2014, 09:58:14 pmThat hardly covers the packing and postage. The transistors are practically free!

author: Tandy
author_rank: Frequent Contributor
timestamp: October 16, 2014, 10:00:03 pm
content: Quote from: barnsleylad on October 16, 2014, 09:54:44 pmSoldering isn't really that difficult, there are some good video tutorials on-line.The common mistake that people make is melting the solder and then trying to apply a blob to the joint. You need to heat both the terminals with the iron and then apply the solder.

author: Richard Crowley
author_rank: Super Contributor
timestamp: October 16, 2014, 10:06:02 pm
content: Get some discarded electronic gadgets and practice soldering. I don't think it is very difficult once you get the "feel" for it.It is the flux that they put inside proper electronic solder that breaks through the oxidation to allow the solder to "stick".Cleaning with IPA probably wouldn't help much. But proper electronic rosin-core solder would do wonders.Portland, Oregon is a popular place for micro-breweries, and "IPA" is probably more familiar as India Pale Ale.

author: Tandy
author_rank: Frequent Contributor
timestamp: October 16, 2014, 10:09:47 pm
content: Something just occurred to me, is that your cable in the photo, does it work?The reason I ask is that it appears that it is a serial link that will output the IR codes. Is there software on your computer to interpret those codes and use them to control iTunes or is that something you are writing?

author: barnsleylad
author_rank: Newbie
timestamp: October 16, 2014, 10:16:15 pm
content: No it's not my cable. It's a cable that used to be available but isn't any longer. Some kind soul took one apart for me so I could build my own. I'll have to write my own software to deal with the IR codes.I'll have a go at soldering my own but I really had a bad experience last time, I'll have a look out for some decent solder, the stuff I used was from Maplins so probably wasn't the best.Lee

author: Tandy
author_rank: Frequent Contributor
timestamp: October 16, 2014, 10:18:58 pm
content: A rosin core lead based solder is usually the easiest for a novice to use.

author: dentaku
author_rank: Frequent Contributor
timestamp: October 16, 2014, 11:34:34 pm
content: Quote from: barnsleylad on October 16, 2014, 09:54:44 pmDave has a good video series on soldering.At 25:20 he even solders a multi-pin connector.

author: sunnyhighway
author_rank: Frequent Contributor
timestamp: October 17, 2014, 05:37:45 pm
content: Quote from: Tandy on October 16, 2014, 10:09:47 pmThe cable on the photo might work. It's the hand drawn schema that doesn't make sense to me.Last time I checked, pin 5 on _any_ RS-232 cable used to be GND.