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Transistor identification?

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  Transistor identification? Look165 <look165@numericable.fr> - 2015-09-06 10:53 +0200
    Re: Transistor identification? John Robertson <spam@flippers.com> - 2015-09-06 09:57 -0700
      Re: Transistor identification? Brian Gregory <bvdvgvrvevgvovrvy@gmail.com> - 2015-09-09 03:38 +0100
        Re: Transistor identification? legg <legg@nospam.magma.ca> - 2015-09-09 11:47 -0400
          Re: Transistor identification? "Ian Field" <gangprobing.alien@ntlworld.com> - 2015-09-17 20:22 +0100
            Re: Transistor identification? legg <legg@nospam.magma.ca> - 2015-09-18 08:55 -0400

#5729 — Transistor identification?

Previous post problem !

444 is 2N444

NPN Germanium  TO5 15V 25mA 150mW 400 KHz  : equivalent AC176 or 2N2430

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#5731

On 09/06/2015 1:53 AM, Look165 wrote:
> Previous post problem !
>
> 444 is 2N444
>
> NPN Germanium  TO5 15V 25mA 150mW 400 KHz  : equivalent AC176 or 2N2430

Germanium? That is quite ancient - any designs from the 1970s on would 
be silicon.

If the OP can check the rest of the device to get an idea of the age 
that would help determine if it is possibly germanium.

John :-#)#

-- 
(Please post followups or tech inquiries to the USENET newsgroup)
John's  Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
(604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games)
                      www.flippers.com
        "Old pinballers never die, they just flip out."

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#5737

On 06/09/2015 17:57, John Robertson wrote:
> On 09/06/2015 1:53 AM, Look165 wrote:
>> Previous post problem !
>>
>> 444 is 2N444
>>
>> NPN Germanium  TO5 15V 25mA 150mW 400 KHz  : equivalent AC176 or 2N2430
>
> Germanium? That is quite ancient - any designs from the 1970s on would
> be silicon.
>
> If the OP can check the rest of the device to get an idea of the age
> that would help determine if it is possibly germanium.
>
> John :-#)#
>

I don't recall ever seeing a germanium device in a modern plastic 
package like that.

-- 

Brian Gregory (in the UK).
To email me please remove all the letter vee from my email address.

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#5738

On Wed, 9 Sep 2015 03:38:00 +0100, Brian Gregory
<bvdvgvrvevgvovrvy@gmail.com> wrote:

>On 06/09/2015 17:57, John Robertson wrote:
>> On 09/06/2015 1:53 AM, Look165 wrote:
>>> Previous post problem !
>>>
>>> 444 is 2N444
>>>
>>> NPN Germanium  TO5 15V 25mA 150mW 400 KHz  : equivalent AC176 or 2N2430
>>
>> Germanium? That is quite ancient - any designs from the 1970s on would
>> be silicon.
>>
>> If the OP can check the rest of the device to get an idea of the age
>> that would help determine if it is possibly germanium.
>>
>> John :-#)#
>>
>
>I don't recall ever seeing a germanium device in a modern plastic 
>package like that.

Only one or two germanium parts in TO92 - AF306 and AF339, but don't
forget plastic RF types in SOT37/TO119 'T' packaging.

If ever there was an electonic industry version of trivial persuit,
this would be a likely question.

RL

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#5755

"legg" <legg@nospam.magma.ca> wrote in message 
news:vhk0vap0db89svkvm5rqdd8qeg3aevnr6j@4ax.com...
> On Wed, 9 Sep 2015 03:38:00 +0100, Brian Gregory
> <bvdvgvrvevgvovrvy@gmail.com> wrote:
>
>>On 06/09/2015 17:57, John Robertson wrote:
>>> On 09/06/2015 1:53 AM, Look165 wrote:
>>>> Previous post problem !
>>>>
>>>> 444 is 2N444
>>>>
>>>> NPN Germanium  TO5 15V 25mA 150mW 400 KHz  : equivalent AC176 or 2N2430
>>>
>>> Germanium? That is quite ancient - any designs from the 1970s on would
>>> be silicon.
>>>
>>> If the OP can check the rest of the device to get an idea of the age
>>> that would help determine if it is possibly germanium.
>>>
>>> John :-#)#
>>>
>>
>>I don't recall ever seeing a germanium device in a modern plastic
>>package like that.
>
> Only one or two germanium parts in TO92 - AF306 and AF339, but don't
> forget plastic RF types in SOT37/TO119 'T' packaging.

The only plastic cased germanium transistors I've ever seen were UHF types 
in TV tuners, AF139 or something like that.

They were pretty fragile - they weren't potted encapsulation, but 2 plastic 
cups glues together to enclose the die header. A few fell apart as I tried 
to unsolder them. 

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#5758

On Thu, 17 Sep 2015 20:22:17 +0100, "Ian Field"
<gangprobing.alien@ntlworld.com> wrote:

>
>"legg" <legg@nospam.magma.ca> wrote in message 
>news:vhk0vap0db89svkvm5rqdd8qeg3aevnr6j@4ax.com...
>> On Wed, 9 Sep 2015 03:38:00 +0100, Brian Gregory
>> <bvdvgvrvevgvovrvy@gmail.com> wrote:
>>
>>>On 06/09/2015 17:57, John Robertson wrote:
>>>> On 09/06/2015 1:53 AM, Look165 wrote:
>>>>> Previous post problem !
>>>>>
>>>>> 444 is 2N444
>>>>>
>>>>> NPN Germanium  TO5 15V 25mA 150mW 400 KHz  : equivalent AC176 or 2N2430
>>>>
>>>> Germanium? That is quite ancient - any designs from the 1970s on would
>>>> be silicon.
>>>>
>>>> If the OP can check the rest of the device to get an idea of the age
>>>> that would help determine if it is possibly germanium.
>>>>
>>>> John :-#)#
>>>>
>>>
>>>I don't recall ever seeing a germanium device in a modern plastic
>>>package like that.
>>
>> Only one or two germanium parts in TO92 - AF306 and AF339, but don't
>> forget plastic RF types in SOT37/TO119 'T' packaging.
>
>The only plastic cased germanium transistors I've ever seen were UHF types 
>in TV tuners, AF139 or something like that.
>
>They were pretty fragile - they weren't potted encapsulation, but 2 plastic 
>cups glues together to enclose the die header. A few fell apart as I tried 
>to unsolder them. 

That's the SOT37/TO119 package intended for stripline UHF. I can
assure you that reputable vendor parts (like AF279 AF280 -
siemens/valvo/telefunken) were encapsulated in solid molded bodies.
I can send you some 'decap' images if you'd like. 

This may have required a two-stage process, initially, but the
construction that you describe, with no die or lead support, in a
plastic shell, would not have survived common manual soldering and
assembly methods.

Even parts assembled inside TO18/TO72 cans (as AF139), or TO1 glass
envelopes, relied on an internal fill/coating, for die and bonding
surface integrity. Even then, niether were expected to survive severe
lead-out mis-manipulation that could occur in careless lead forming or
point-to-point wiring assembly methods.......

Earliest pro-electron germanium parts in SOT37 were AF2xx or higher.
In TO92, only the two numbers listed previously. All low power
VHF/UHF.

RL

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