HISTORY
The days of Germanium transistors have long since passed but while sorting through one of my many boxes of goodies to find new homes for, I noticed this group of 'likely looking lads' all hiding in a corner of the box, anticipating the day when they may need to 'thermal runaway' from those nasty Silicon boys that may be passing by.
Hmmmm ... that may seem a bit strange but electronics can be such a 'dry' subject and with my 'creative side' working at full steam in my twilight years, I like to tell a story or two, giving these mundane semiconductors a bit of a 'personality'
On the packet I had written that these were extracted from IBM 1970's card reading equipment but nothing more about them so some basic tests and observations are detailed below ...
IBM (USA) - Vintage Transistor
Circa 1970's
Dominantly PNP type but a couple of NPN's are also present
All are TO-5 metal cases
All are Germanium junction transistors
Although these were extracted from IBM equipment, I cannot establish who manufactured the transistor devices.
Keep in mind that as these were used primarily for switching, their use in analog circuits may not result in great performance - that is for the experimenter (new owner) to establish themselves.
These have been sorted into groups based on the underside appearance as there are no body markings I can use for identification.
Each grouping is now in their own little packet and some have had the hFE written on the side of the case after testing.
Dark Brown underside - Tin leads
PNP
hFE 62
Light Brown underside - Gold leads
NPN
hFE 145, 219
PNP
hFE 67
Green underside - Tin leads
PNP
hFE 66, 76, 41
All metal underside with small resin exit point for two of the leads - Tin leads
PNP
hFE 122, 184, 155, 73, 47, 45, 40
NPN
hFE 77
Special note: the 'top' of the triangular lead pattern is connected to the case and is the BASE
COSMETIC CONDITION:
USED Extracted from IBM boards many years ago
Clean although the tinned leads do have some oxidisation - I was still able to easily test each transistor without cleaning the leads though.
NO identifiable markings on any of the devices that I could find, not even codes of any kind. I cannot see signs of any previous print rubbing off, it just seems to have never been there! That must have made assembly of the PCB's very interesting!
Lead lengths are all a minimum of 2.5mm (they were all originally mounted flat to the PCB substrate)
Free of solder 'dags'
I have now placed these Germanium transistors into sealed packets, according to how they look from the underside and with some having notably different hFE measurements indicated on the casing so that I can easily find particular devices if need be.
I will supply a selection (even just one) or take the whole lot (yes please! they like to move around as a 'gang' - safety in numbers in case they are cornered by a bunch of aggressive 'Silicon boys' - an automatic discount applies in the latter case.
