The earliest semiconductor devices used idiosyncratic naming and numbering conventions determined solely by their manufacturers. However this did not last, and various national and international standards came into existence across the world in the 1960s.

In Europe, the Pro Electron type designation and registration system for active components was set up in 1966 in Brussels, Belgium. In terms of the early types of diodes and transistors, the system was:

Devices with such a standardised type number may be made by multiple manufacturers.

As well as standardised pro-Electron numbering, most of these types use a standardised JEDEC device packaging, or 'outline' as it is known. Diode shapes were specified in the DO series of outlines, and transistors in the TO series. However, a number of types with pro-Electron naming use earlier, idiosyncratic, outlines. The majority of commercial devices fall under one of only a few outlines. These outlines are fully specified in JEDEC documents held in their archive, with separate pages for diodes and transistors. A login is necessary, but anyone with a bona-fide reason can register.

I'm mainly interested in germanium devices, so just for fun (and to increase my knowledge) here are the types, starting with the lowest-numbered, in each of the above categories. I've tried to include all the types in each category except where there are too many. The documentation that I used to compile this is old and not entirely reliable. In particular there are several lesser-known manufacturers from the remoter parts of Europe that may have made such types, but they are rarely seen and I may have missed some types. If you see errors or omissions, please do inform me.

I am seeking examples of a number of these: I have indicated them in red. NB I usually only want manufacturer-branded examples. (This does not mean that I possess all the rest, I have just selected those that I find particularly early or unusual). If you can tell me where I might find any, please

Low-power/small-signal germanium diodes:

Most of these are point-contact diodes in miniature axial glass outline.

AA111 diode
AA116 diode
AA120 diode
AA129 diode

Industrial germanium diodes:

AAY18 quad diode
AAY43 quad diode
AAZ23 diode

Germanium rectifying diodes:

AY105K diode

Germanium industrial rectifying diode:

The only one seems to be:

But I am suspicious about the very similarly numbered AAY10-120.

Germanium varicap diodes:

The defined type is ABnnn, but there are none that I can find.

Low-power/small-signal germanium transistors:

AC106 transistor AC105 transistor
AC107 transistor
AC115 transistor AC114 transistor AC113 transistor
AC129 transistor

Industrial low-power/small-signal germanium transistors:

ACY27 transistor

High-power germanium low-frequency transistors:

AD105 transistor
AD138 transistor
AD142 transistor
AD149 transistor

Industrial high-power germanium low-frequency transistors:

ADY11 transistor
ADY22 transistor
ADZ11 transistor

Germanium tunnel diodes:

Germanium industrial tunnel diodes:

Low-power germanium high-frequency transistors:

AF102 transistor
AF116 transistor

and many more up to AF439 but with many gaps in numbering. Some of the more interesting are:

AF128 transistor

A number of the higher-numbered AF types are RF types in plastic encapsulation.

Industrial germanium high-frequency transistors:

Germanium high-frequency, high-power transistors:

AL112 and AL113 transistors

Germanium industrial high-frequency, high-power transistor:

In fact, this is only a 250 mW type, so why it fits in the category L is a bit unclear.

ALZ10 transistor

Industrial germanium switching transistors:

I don't know why, but there are no non-industrial switching transistor types of the form ASnnn.

ASY14 transistor ASY13 transistor ASY12 transistor
ASY32 transistor
ASZ20 transistor
ASZ30 transistor
ASZ101x transistors

High-power germanium switching transistors:

These are uncommon, and all the examples I have seen are unbranded.

High-power industrial germanium switching transistors:

AUY10 transistor AUZ11D transistor AUZ11 transistor