where to find germanium TO-220 PNP NPN

whats the part numbers?

Germanium transistors cannot be passivated like silicon, so they have to be packaged in a hermetically sealed package. If a germanium device was mounted in a TO-220 epoxy package, the plastic would contaminate the chip and it would soon quit working.

The parts are house numbered. I can't cross them to anything.

Are they so shorted that you can't measure any of their junctions? You should be able to measure one and you will find that the junction will have about 0.6V across it, hence it's a silicon device.

Measure the supply voltage and get some high power silicon transistors in the TO-220 package that have a higher voltage rating than the supply voltage. Or maybe change to the TO-3P plastic package, which is rated for more than a hundred watts with a decent heat sink.

Paraphrasing the thread so far... Help me find germanium transistors. What are the part numbers? I'm not tellin'...

Don't suppose it's ever occurred to you that some of us might have salvaged germanium transistors from old gear and stashed them away.

I probably can't help cause the ones I saved look like a TO-220 with a tab out each side instead of the top. mike

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So how can Germanium be used in plastic TO housings? Must they always be in glass? I have ann application requiring germanium in TO92, a special component that will be build as special. I am wondering how this could be done?

Regards,

Pieter Hoeben

to

was

I have never seen or read of any germanium device being packaged in a package that had the chip in contact with the plastic or silicone package, as is usually done with silicon devices.

Some manufacturers, Raytheon may have been one, made very small germanium transistors for hearing aids. I have read that Raytheon later made the CK722 and its sisters in a smaller package that was then repackaged in the normal CK722 package so that it conformed to their product line. Check out the X-ray picture on this web page

And this web page So you may be able to find germanium transistors that will fit in the space of a TO-92 package.

See these URLs for more info.

There were very few TO220 parts in existence when the KLH21 desk-top FM radio was made, but germanium transistors were common. Power stages often used TO-1 or X-04 germaniums for a couple of watts output.

Please copy the part number of the suspect device or indicate the part's location / ID in the schematic.

A bad output is a symptom that can be caused by faults anywhere or everywhere in this unit. Troubleshooting a radio will generally involve starting at the INPUT to the device.

RL

My mistake. The preceding comments are more applicable to earlier models.

The KLH21 was made in '78. TO220 plastic silicon transistors were commodities by then, and germanium parts of any shape or size were unlikely to see power applications in a new product (still common in rf and in portable products then).

RL

Sams photofact 1357-SED has the schematic and was published in 1973. i don't have a copy in my collection.

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Michael A. Terrell
Central Florida

Maybe there a confusion between "german" and "germanium"???

I have never seen a TO-220 Germanium, but a lot of Silicium TO-220 with the "European-German" notation BDxxx or so. And i know some K&H-Active Speakers from the mid/end of the sixties which already uses silicium transistors (RCA-Series 40406-40411 i think to remember). I don't think that K&H uses germanium again in newer designs. I would expect that the BD243B-BD244B types of transistors would do the job as they are state of the art in the mid seventies. Google for BD243 and you find the farichild data sheet.

Jorgen

You may be right. "Silicium" is called "silicon" over here...

And "Silicon" here means the opaque glue for the bathroom or to glue glass to build an aquarium or so...

Funny translation errors ;-)

Jorgen

Ah! That is what we call "silicone".

"Silicon" = Si, the element

"Silicone" = large molecule Si compounds

At least in American English, today, at the current phase of the moon :)

in

Google

We call it silicone glue or silicone seal, also RTV which was GE's abbreviated term, Real Time Vulcanizing.

How about Room Temperature Vulcanizing

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Oops. Yeah, that sounds more like it.

Correct. How about Dow Corning, rather than GE, too?

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I think it was actually GE. Both are now heavily into silicone products, but D-C is probably more commonly associated with them.

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