Path: csiph.com!eternal-september.org!feeder.eternal-september.org!mx02.eternal-september.org!.POSTED!not-for-mail From: Phil Hobbs Newsgroups: sci.electronics.basics,sci.electronics.components,sci.electronics.design,sci.electronics.repair,alt.engineering.electrical Subject: Re: Transistor identification? Date: Fri, 18 Sep 2015 10:50:55 -0400 Organization: A noiseless patient Spider Lines: 51 Message-ID: <55FC24CF.8090600@electrooptical.net> References: <0001HW.1B9B87FD00098A2611E4F83CF@news.eternal-september.org> <0001HW.1B9BFB3100248A5811E4F83CF@news.eternal-september.org> <2kEKx.352107$nx.26794@fx16.am4> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Injection-Info: mx02.eternal-september.org; posting-host="7f274aa16eb7662e9246b4f248fa3066"; logging-data="27303"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1/7KN3juUvs+AsVJ5pi1E1F" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.2.0 In-Reply-To: Cancel-Lock: sha1:DdqRgaxqQvKRpVlWZT8qL4uhc8Q= Xref: csiph.com sci.electronics.basics:46252 sci.electronics.components:5759 sci.electronics.design:377486 sci.electronics.repair:67929 alt.engineering.electrical:16621 On 09/17/2015 08:05 PM, krw wrote: > On Thu, 17 Sep 2015 20:16:17 +0100, "Ian Field" > wrote: > >> >> "DaveC" wrote in message >> news:0001HW.1B9BFB3100248A5811E4F83CF@news.eternal-september.org... >>>> How's it measure? >>>> >>>> (Or if it's dead, is there another one probably working that you can >>>> test?) >>>> >>>> Tim >>> >>> Dead. Other with identical markings measure as NPN. What else to determine >>> from measurements? >> >> You can usually distinguish the B/E junction because it will zener somewhere >> around 5 - 8V ish. >> >> You need to keep the test current pretty low - you can get ultra-efficient >> LEDs that give a useable indication at only 2mA. Hook one of those up with >> an A23 12V keyfob battery and a current limiting resistor. > > InGaN (true) green LEDs are quite bright at only 1mA. They can be > seen at much less than that. > An ordinary 4-3/4 digit DVM on the lowest volts range (400 mV usually) makes a poor man's picoammeter. The 10 megohm ones read 1 LSB (0.01 mV) for 1 pA. Some of the older ones, where the lowest range doesn't have the 10M resistor in parallel, can be much more sensitive than that. You aren't going to hurt a transistor with a nanoamp of reverse base current, and the measurement is pretty simple. Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 hobbs at electrooptical dot net http://electrooptical.net