Case styles and mystery component

1) is there a resource on the 'net that has
diagrams of the various semiconductor case types?
I mean like the old TO-series stuff, to the new
SMT cases. I'm trying to ID an old part I found,
and I don't even know what the case designator is
(see 2).

2) It's an all-metal case, threaded at one end, a
knurled metal midsection, and two lug-type
connectors at the other end.
The lettering reads "DPC209 RCA 8432"

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The one reference I could find thought it might
be an SCR, but said nothing more about it.

 

How big is this thing? The numbers are probably house numbers,
but the "RCA" kinda rings a bell. ;-) The stud is supposed to
bolt to a heat sink, and the other two things are either the
emitter and base of a power transistor, or the cathode and gate
of an SCR, or MT2 and gate of a triac, in which case the case
would be MT1.

Do you know how to ohm out a transistor? Put your ohmmeter in
"diode test" mode, and a transistor will look like two diodes,
back-to-back. The polarity of the measurements will tell you
if it's PNP or NPN, and the forward drop will tell you if it's
silicon or germanium. Yes, this package is so old that it might
actually be a germanium power transistor.

But, if your reference says "SCR", then I'd test that theory.
Set up a little circuit with a power supply of a few volts,
say 3 or 6 or whatever. Put some kind of load from the stud
(which we're guessing is the anode) to the positive end of
the supply. Come to think of it, a flashlight bulb would be
ideal - just match the supply voltage!

The cathode will be the heavier lug - just connect that to the
negative supply.

Set that up, and take maybe a 100K resistor and touch it to both
the anode (the case) and the gate (the smaller of the two tabs)
and if it's an SCR, the light bulb will come on and stay on.

If it's an NPN transistor, the light will come on weakly, depending
on the value of the resistor that you've got from what turns out
to be the collector to what's evidently the base.

Well, you get the idea.

Have Fun!
Rich

 

I would opine that the "8432" is the date code which makes it unlikely
to be a germanium device. I also strongly suspect it will be an SCR.
If this is the case, the stud is Anode, the longer terminal is Cathode
and shorter terminal is Gate.

Depending on gate sensitivity 100K may be too high. 1K is fine for
higher power SCR's.

 

Thyristor is very likely. You can find them with google but haven't found a
description yet.
http://www.emporiumpartners.com/?p=partsearch&q=dpc209+rca

Graham

 

8432 looks like a date code,
RCA could be the manufacturer
that'd make DPC209 the part number.

K G

I've also seen triacs in that case.

Bye.
Jasen

 

Hi, Mr. Day. In days of yore, the package you're describing ruled the
earth. It was called "press-fit", and was the standard package for
power thyristors like triacs and SCRs. The idea was, you'd drill a
hole of standard diameter into the aluminum heat sink (which was at
least 1/4" thick), and then use an arbor press to press the package
into the hole. The knurling on the sides would ensure a good thermal
contact between the aluminum and the package itself. Note that the
semiconductor die is actually on the inside bottom of the package can,
so for this type of package, the heat has to travel internally from
the bottom of the package to the sides to be dissipated externally.
In short, lame for several reasons.

Usually, the online database for IC and semiconductor packages is the
manufacturer data sheets. If a mechanical drawing isn't on the
datasheet, it will be referenced and available on the web.

Unfortunately, the press fit stuff just isn't made any more. You'd
have to rely on old data books or such. Your part is a "house
number" (not a standard GE part number -- they used to label standard
semis with the customer P/N instead of standard to "make" the customer
buy replacemnts from the customer and not repair it themselves(?!?!).
That makes it worse.

If you can get a standard part number, I'd suggest going to the NTE
site. The NTE cross-reference data sheet will tell you what the JEDEC
package is called, and also provide a mechanical sketch.

http://nte01.nteinc.com/nte/NTExRefSemiProd.nsf/$$Search?OpenForm

Good luck
Chris

 

Umm No !

This one has the threaded stud.

Graham