[sdiy] Why transistors arent square!

[Roy J. Tellason]

On Sunday 15 February 2009 08:11:01 am Ingo Debus wrote:
> Am 15.02.2009 um 00:14 schrieb Graham Atkins:
> > On 14 Feb 2009, at 22:46, karl dalen wrote:
> >> This cumbersome half-moon shaped packaging are drag!
> >> If the packages had been square, stacking and leveling to
> >> cooling or heating surfaces would have been a breeze!
> >
> > They have to make them like that so that sdiy'ers know which
> > way to put them on the PCB........Ouch !!! (I'll duck now shall I ?)
>
> Joking aside, I think this is indeed one possible reason. If
> transistors were in a square package, with three leads in the middle
> of the package in a line, they'd at least need some marking. Much
> like DIL ICs. BTW, there are/were some transistors in a square-ish package.
> Was that Ferranti?

There have been a number of them...

> I often wondered why DIL packages are the way they are. If there was
> on one side one lead more than on the other side, it would be impossible to
> insert them the wrong way.

Way back in 1975 I worked on some industrial equipment that used these parts 
called "norbits",  a very strange logic family that would run off either 12V 
or 24V,  and those came in 17-pin packages.  But not your typical DIP,  these 
were over half an inch thick and over an inch from one side to the other!

> Tubes, on the other hand,  can never be inserted wrongly. At least I don't
> know of any tube sockets that allow for that.

Octal tubes,  once the keying bit breaks off,  can be inserted in a number of 
different wrong ways.   :-)


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