Groups > sci.electronics.components > #5759

Re: Transistor identification?

From	Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net>
Newsgroups	sci.electronics.basics, sci.electronics.components, sci.electronics.design, sci.electronics.repair, alt.engineering.electrical
Subject	Re: Transistor identification?
Date	2015-09-18 10:50 -0400
Organization	A noiseless patient Spider
Message-ID	<55FC24CF.8090600@electrooptical.net> (permalink)
References	<0001HW.1B9B87FD00098A2611E4F83CF@news.eternal-september.org> <msg61e$b4m$1@dont-email.me> <0001HW.1B9BFB3100248A5811E4F83CF@news.eternal-september.org> <2kEKx.352107$nx.26794@fx16.am4> <l6lmvapme55i8iseujq12jdo1fs69tl6ma@4ax.com>

Cross-posted to 5 groups.

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On 09/17/2015 08:05 PM, krw wrote:
> On Thu, 17 Sep 2015 20:16:17 +0100, "Ian Field"
> <gangprobing.alien@ntlworld.com> wrote:
>
>>
>> "DaveC" <not@home.cow> 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

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Thread

Transistor identification? DaveC <not@home.cow> - 2015-09-05 13:28 -0700
  Re: Transistor identification? DaveC <not@home.cow> - 2015-09-05 14:18 -0700
    Re: Transistor identification? DecadentLinuxUserNumeroUno <DLU1@DecadentLinuxUser.org> - 2015-09-05 20:03 -0400
    Re: Transistor identification? John Robertson <spam@flippers.com> - 2015-09-05 21:52 -0700
      Re: Transistor identification? DaveC <not@home.cow> - 2015-09-05 23:05 -0700
        Re: Transistor identification? John Robertson <spam@flippers.com> - 2015-09-06 00:05 -0700
        Re: Transistor identification? piglet <erichpwagner@hotmail.com> - 2015-09-06 08:11 +0100
  Re: Transistor identification? "Tim Williams" <tmoranwms@charter.net> - 2015-09-05 20:52 -0500
    Re: Transistor identification? DaveC <not@home.cow> - 2015-09-05 21:40 -0700
      Re: Transistor identification? "Tim Williams" <tmoranwms@charter.net> - 2015-09-06 13:03 -0500
      Re: Transistor identification? "Ian Field" <gangprobing.alien@ntlworld.com> - 2015-09-17 20:16 +0100
        Re: Transistor identification? krw <krw@nowhere.com> - 2015-09-17 20:05 -0400
          Re: Transistor identification? Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2015-09-18 10:50 -0400
  Re: Transistor identification? N_Cook <diverse@tcp.co.uk> - 2015-09-06 07:46 +0100
    Re: Transistor identification? John Robertson <spam@flippers.com> - 2015-09-07 13:29 -0700

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