Hughes International (UK) logo

Hughes International (UK) was part of the US company Hughes Aircraft. It established a high-tech semiconductor factory in Glenrothes, Scotland, about 1960 (part of the so-called 'silicon glen'). This facility seems to have manufactured primarily diodes, both germanium and silicon. The company logo was a large capital 'H'.

Hughes International (UK) logo

At some point, EMI obtained a 49% holding, and the company was renamed EMIHUS Microcomponents Limited (EML), but retained the 'big H' logo. Later, EMI sold their holding back to Hughes, which became Hughes Microelectronics. Then in 1975 Hughes Microelectronics merged with Raytheon and became Raytheon Systems. There is little detail of these changes on the Net.

The only source of data that I possess on Hughes International's products is a booklet 'All Products Catalogue' dated May 1965. This does include a good number of silicon transistors and the introduction states the products are '... produced ... at Glenrothes ...'. However, the majority are 2N series types that may have been shipped from the US.

I have relatively few Hughes International devices.


The catalogue starts with a section on 'germanium signal diodes' comprising four series:

  • point-contact general purpose diodes HG1001 - HG1012, HG1083, HG1087
  • gold bonded computer diodes HG5001 - HG5010, HG5076
  • fast recovery computer diodes HG1810 - HG1812, HG1840 - HG1842, HG1870 - HG1872
  • ultra fast recovery computer diodes HPS1670 - HPS1672, HPS1672A

The images show an HG1005 and an HG5009 used on circuit cards from a LEO III computer.

HG1005 diode HG5009 diode

A number of the above are type-approved in the UK military CV series. The ones in the 1963 Register are:

CV9401 = HG1001       CV7041 = HG1005       CV10032 = HG1005       CV7130 = HG1006
CV10691 = HG1007 CV9414 = HG1010 CV8636 = HG1012 CV9725 = HG1086
CV10825 = HG1087 CV7127 = HG5004 CV10089 = HG5004 CV10227 = HG5008
CV9694 = HG5009 CV9176 = HG5081 CV10226 = HG5085

I think these CV7127 are Hughes-made, although they do not bear any manufacturer or date code. CV7127 has prototypes HD2595, 85P1, AAY12, AAZ17, and HG5004.

CV217 diode

Next follows a section on 'silicon switching diodes' comprising two series:

Two of the planar epitaxial diodes are type-approved in the UK military CV series.


Then a section covers 'Zener diodes' comprising two series:


Then a number of sections on other diodes that I shall not list in detail:


HT101 transistor

Then we come to transistors. There are five sections of normal transistors, nearly all 2N types. I list only the non-2N ones:

There are also two sections on silicon 'glass ambient' transistors: GAT1000 - GAT1003 and GAT2000 - GAT2002.

A number of the above transistors are type-approved in the UK military CV series. The only ones in the 1963 Register are: