Previous post problem !
444 is 2N444NPN Germanium TO5 15V 25mA 150mW 400 KHz : equivalent AC176 or 2N2430
Previous post problem !
444 is 2N444NPN 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
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.
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
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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