What Ger PNP transistors do I use for the following circuit in a
radio: HF AMPLIFIER, MIXER; LF AMOPLIFIER, DRIVER and AUDIO OUTPUT?

Does anyone know whether the numbers of the trasnsistors are
standardized? Or each manufacturer use its own? It seems that there
are tons of numbers out there such as 2N107, 2N239, 2S678,  etc.......

God Bless!

Daniel

 (d...@ferris.edu) writes:
> What Ger PNP transistors do I use for the following circuit in a
> radio: HF AMPLIFIER, MIXER; LF AMOPLIFIER, DRIVER and AUDIO OUTPUT?
> 
You don't.

Germanium transistors were pretty much obsoleted forty years ago, by
silicon transistors.  There is a far better range of silicon transistors,
and generally they have far better specs than germanium transistors.

The only reason you'd use a germanium transistor at this time is if
there was a specific reason for using germanium.  There are still some
things where germanium transistors can be useful, which is why some
are still being manufactured, but the average hobbyist wouldn't have
need for those uses.  And there is no reason to use germanium transistors
in a radio.

If you are looking for germanium tranistors because you have a schematic
that uses them, and then you can't find the devices specified, it's because
the schematic is decades old and you need to drop that schematic and
find soemthing more modern, than try to find germanium transistors
to use in the schematic.

The reason some of us have germanium transistors lying around is because
we accumualted them decades ago, when they were still common.  Beyond
taht, you'll have to go out of your way to get them.

  Michael

> Does anyone know whether the numbers of the trasnsistors are
> standardized? Or each manufacturer use its own? It seems that there
> are tons of numbers out there such as 2N107, 2N239, 2S678,  etc.......
> 
> God Bless!
> 
> Daniel
> 

"Michael Black" <e...@FreeNet.Carleton.CA> wrote in message 
news:eteut1$p2o$1...@theodyn.ncf.ca...
> (d...@ferris.edu) writes:
>> What Ger PNP transistors do I use for the following circuit in a
>> radio: HF AMPLIFIER, MIXER; LF AMOPLIFIER, DRIVER and AUDIO OUTPUT?
>>
> You don't.
>
> Germanium transistors were pretty much obsoleted forty years ago, by
> silicon transistors.  There is a far better range of silicon transistors,
> and generally they have far better specs than germanium transistors.
>
> The only reason you'd use a germanium transistor at this time is if
> there was a specific reason for using germanium.  There are still some
> things where germanium transistors can be useful, which is why some
> are still being manufactured, but the average hobbyist wouldn't have
> need for those uses.  And there is no reason to use germanium transistors
> in a radio.

The OP might want to preserve originality while repairing an old radio, 
otherwise I'd select a fairly ordinary silicon PNP type and tweak the bias 
if necessary. 

On Mar 16, 3:02 pm, d...@ferris.edu wrote:
> What Ger PNP transistors do I use for the following circuit in a
> radio: HF AMPLIFIER, MIXER; LF AMOPLIFIER, DRIVER and AUDIO OUTPUT?
>
> Does anyone know whether the numbers of the trasnsistors are
> standardized? Or each manufacturer use its own? It seems that there
> are tons of numbers out there such as 2N107, 2N239, 2S678,  etc.......
>
> God Bless!
>
> Daniel

Hi, Daniel.  I've got to assume you're working with an existing radio
circuit, probably an older one made in the 1960s when germanium PNPs
and negative supplies (positive GND) ruled the earth.  Those were the
days.

Here's the drill.  Find the standard JEDEC 2N number, either in the
schematic or printed on the body/case of the transistor.  Then go to
this link:

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

and type in the manufacturer part number for the transistor.  The NTE
cross reference will probably work for you.  NTE parts are available
at many different places, including many TV/radio repair shops.  You
can also get these online at many places.  You can go to their main
page:

http://nteinc.com/

to find a distributor.

Good luck
Chris

Michael Black wrote:

>  (d...@ferris.edu) writes:
> 
>>What Ger PNP transistors do I use for the following circuit in a
>>radio: HF AMPLIFIER, MIXER; LF AMOPLIFIER, DRIVER and AUDIO OUTPUT?
>>
> 
> You don't.
> 

That's right, unless it's hobby and there are tons of them in the box. 
My favorites were AC127 for audio, AF126 up to FM band, and AF239 for 
the really hot stuff.


> Germanium transistors were pretty much obsoleted forty years ago, by
> silicon transistors.  There is a far better range of silicon transistors,
> and generally they have far better specs than germanium transistors.
> 
> The only reason you'd use a germanium transistor at this time is if
> there was a specific reason for using germanium.  There are still some
> things where germanium transistors can be useful, which is why some
> are still being manufactured, ...


Where? Where?    <drool>

All I've found so far was new old stock so it can't be used in any new 
design. Ge would be really handy for very low voltage applications such 
as starter circuitry for a single fuel cell converter.


>                    ... but the average hobbyist wouldn't have
> need for those uses.  And there is no reason to use germanium transistors
> in a radio.
> 
> If you are looking for germanium tranistors because you have a schematic
> that uses them, and then you can't find the devices specified, it's because
> the schematic is decades old and you need to drop that schematic and
> find soemthing more modern, than try to find germanium transistors
> to use in the schematic.
> 
> The reason some of us have germanium transistors lying around is because
> we accumualted them decades ago, when they were still common.  Beyond
> taht, you'll have to go out of your way to get them.
> 

And that accumulation habit has rescued my old Minolta camera where I 
really needed a Ge diode. The old OA91 works like a champ after being 
boxed up for about three decades.


>   Michael
> 
> 
>>Does anyone know whether the numbers of the trasnsistors are
>>standardized? Or each manufacturer use its own? It seems that there
>>are tons of numbers out there such as 2N107, 2N239, 2S678,  etc.......
>>
>>God Bless!
>>
>>Daniel
>>
> 
> 
> 

-- 
Regards, Joerg

http://www.analogconsultants.com

On Fri, 16 Mar 2007 22:19:02 +0000, ian field wrote:

> 
> "Michael Black" <e...@FreeNet.Carleton.CA> wrote in message 
> news:eteut1$p2o$1...@theodyn.ncf.ca...
>> (d...@ferris.edu) writes:
>>> What Ger PNP transistors do I use for the following circuit in a
>>> radio: HF AMPLIFIER, MIXER; LF AMOPLIFIER, DRIVER and AUDIO OUTPUT?
>>>
>> You don't.
>>
>> Germanium transistors were pretty much obsoleted forty years ago, by
>> silicon transistors.  There is a far better range of silicon transistors,
>> and generally they have far better specs than germanium transistors.
>>
>> The only reason you'd use a germanium transistor at this time is if
>> there was a specific reason for using germanium.  There are still some
>> things where germanium transistors can be useful, which is why some
>> are still being manufactured, but the average hobbyist wouldn't have
>> need for those uses.  And there is no reason to use germanium transistors
>> in a radio.
> 
> The OP might want to preserve originality while repairing an old radio, 
> otherwise I'd select a fairly ordinary silicon PNP type and tweak the bias 
> if necessary.

I've repaired several old time transistor portables using germaniums
scavaged over the years from all sorts of 60's portable crap. And that
relates a lot with how I got my start with this stuff back in the
60's. But I agree that if this is an experimental or kit that the OP needs
to find something more current dated unless he's just into that kind of
stuff.

-- 
Pierre Salinger Memorial Hook, Line & Sinker, June 2004

COOSN-266-06-25794
 

Michael:
Thanks for your education. But I have an old 4-transistor superhet.
radio schematic and my kits
want to build this radio. So I want to find out what Ge transistors I
need. My radio
knowledge is severely limited, but I know the first transistor is very
different from the
last two (a pair) that do the audio output job.

Best! Daniel

Thanks, Chris, for your help. I tried the Web sites. Fantastic!
Best!   Daniel

<d...@ferris.edu
>
> Thanks for your education. But I have an old 4-transistor superhet.
> radio schematic and my kits
> want to build this radio. So I want to find out what Ge transistors I
> need.



**  You will have to post that schematic somewhere.

  BTW

  Why are no transistor numbers on it?



.....   Phil

<d...@ferris.edu> wrote in message 
news:1...@b75g2000hsg.googlegroups.com...
>
> Michael:
> Thanks for your education. But I have an old 4-transistor superhet.
> radio schematic and my kits
> want to build this radio. So I want to find out what Ge transistors I
> need. My radio
> knowledge is severely limited, but I know the first transistor is very
> different from the
> last two (a pair) that do the audio output job.

Where will you find the other parts? Loopstick, tuning capacitor, IF 
transformers and audio transformers?

http://www.rpelectronics.com/Default.asp?Main=/English/OnlineCat.asp?Menu=/English/Content/Categories/CatM_95.asp%26Deta
il=/English/Content/Divisions/Div_95_650.asp