[sdiy] newbie alert - transistor question

[groovyshaman]

Hi Cynthia -

Interesting.. Thank you for the insight.  Funny, the datasheets spec out
the same for the two packages, except for the junction temps.  (I looked
at STMicro parts.)  Lies and more lies, I guess!

just finished Pease's book on troubleshooting and got lies on the brain...
:)

George

----- Original Message ----- 
From: "Cynthia Webster" <cynthia.webster at gte.net>
To: "groovyshaman" <groovyshaman at snet.net>; "sdiy group"
<synth-diy at dropmix.xs4all.nl>
Sent: Tuesday, January 04, 2005 9:24 PM
Subject: Re: [sdiy] newbie alert - transistor question


> on 1/4/05 6:02 PM, groovyshaman at groovyshaman at snet.net wrote:
>
> > Hopefully this isn't too brutal of a common knowledge question!
>
> Hi George!
>
> > Ok, I'm in the process of ordering some 2N2222A transistors for a few
> > projects I working on (one of them is a Blacet dark star - finally).
And
> > so I have come upon a strange question: is there any advantage to
buying
> > them in TO-18 cans over TO-92 plastic?  Why do they still make cans?
> > Should I even be concerned with this?  I've been reading lies.. err..
> > datasheets, googling, etc. but other than the cans handling slightly
> > higher junction temps, I just don't see the benefit in spending 30
bucks
> > more for 100 pieces O' TO-18.  (Besides, if they're anywhere near 150C
> > I've likely got a much bigger problem!)  I appreciate any thoughts,
> > strange or otherwise! :)
>
> There are a few of us who think that the metal can versions "sound
better"
> in certain applications.  It was my experience when switching between
> metal can and plastic bodied 2N2222s while building the Steiner Filters.
>
> I prefer the metal, but it is a very subtle improvement.
> As far as ~why~ well... the slew rate of the plastic ones are faster
> because the metal ones have to drag around the capacitance of the
> metal can itself, and thus the plastic body transistors are best suited
> for higher speed applications.
>
> It most likely will not matter much in our applications,
> but with weaker transistors than the mighty 2N2222, the metal can
> capacitance phenomenon may be even more of a boat anchor?
> >
> > PS: I've lurked (mostly) on this list now for over three years and it
> > continues to amaze me how much knowledge there is here, and how much I
> > have to learn.
>
> Me too, always so much to learn around here
> (Thanks Everybody!!)
>
> Cynthia

<snip>