[sdiy] Pin Outs

[Scott Nordlund]

Should be easy for a JFET since it's a PN junction, right?  If it's 
N-channel, you know the gate is P and the source/drain are N.  So you 
can use a diode tester to identify the gate, since it will  conduct only
when the positive voltage is on the gate.  The source/drain pins, which 
should be interchangeable (as far as I know) will measure the same each
way.

----------------------------------------
> From: dingebre at 3dphysics.net
> To: synth-diy at dropmix.xs4all.nl
> Date: Tue, 23 Feb 2010 10:49:13 -0700
> Subject: [sdiy] Pin Outs
>
> I am not finding a data sheet (well, at least one with any extensive info)
> or pin-outs for a couple of obsolete parts.
>
> 2N5163 n channel jfet
> 2n4891 UJT
>
> The basic question is, is there a "hand test" I can do to determine the
> pin-out for sure?
>
> I have a simple circuit I could breadboard for the UJT, but nothing really
> for the JFET.
>
> I have some "replacement" parts which have appropriate pin outs printed on
> the envelope they came in, but I also have some of the original vintage
> parts which I would rather use.
>
> The component packages between the original parts and the replacements are
> different subtly.
>
> To complicate matters, I have two vintage version of the 2n5163, in similar
> but different packages, one is a TO-106 I think with a flat side by one pin,
> one does not have a flat on it at all.
>
> JFET:
> . apex
> Pins are in a triangle . . base of triangle
>
> Package 1: TO-106(?) round with round top flat is offset adjacent to one of
> the pins (vintage)
>
> .
> Flat . .
>
> Package 2: TO-106(?) round with round top, flat opposite middle pin,
> parallel to base of the triangle (new replacement)
>
>
> .
> . .
> Flat
>
> Package 3: TO-106(?) round with round top, no flat (vintage)
>
> UJT
>
> Pins are in a triangle, metal housing with a tab
> Package 1: TO-18(?) tab between triangle apex pin and a triangle base pin
> (new replacement)
>
> .
> tab . .
>
> Package 2: TO-18(?) tab at an angle, but is between the two triangle base
> pins.
>
> .
> . .
> tab
>
> I found some old schematics which suggest two different pin-outs for the
> JFET, Source, Gate, Drain, and Source, Drain, Gate, both suggesting a TO-106
> round top package was used, but I'm not sure.
>
> I have struck out completely on the UJT. Believe me, I have searched every
> internet datasheet archive I could find.
>
> I have a simple schematic for the UJT which I guess I can breadboard and try
> the replacement I know the pin-out for and then try an old part to see. But,
> I'm a bit at a loss for the JFET.
>
> Thanks
> David
>
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