Philips logo The electrical giant Philips of the Netherlands was for many years the dominant manufacturer of semiconductors in Europe. When Bell Labs announced the discovery of the transistor, Philips was quick to understand its potential and to establish research and manufacturing capabilities. Philips' headquarters is in the Netherlands but it also established research and manufacturing plants in the UK, under its subsidiary Mullard Ltd., and in West Germany under the Valvo subsidiary. The three countries all produced the same transistor product lines, starting with the original OC series of germanium transistors and OA series of germanium diodes.

Philips has a logo based on a shield as shown, but sometimes also just uses its name in capitals. However it never printed either of these on its transistors or diodes (although it did on their boxes), whereas Mullard and Valvo usually did print their name. Therefore unbranded OC transistors, for instance, are most likely made in the Netherlands by Philips (and are sometimes printed MADE IN HOLLAND).

Van der Heem logo However, Philips were not the only Dutch company selling transistors: they were also marketed by a company called Van der Heem, and their customer Amroh. I give more details if this below but information is scarce so if you know about Van der Heem semiconductors, please

I do not possess all the transistors below, in fact I am seeking many of them. It is noted in the text where I am seeking examples of any particular type. If you have some for sale or exchange, please


The history of Philips' first transistors is the subject of some excellent research and documentation by Mark Burgess, a fellow enthusiast. My own page on Mullard Ltd contains information and images of many of the early devices from the Philips group. I shall therefore not repeat such information here.


OC13H transistor

However there is one oddity, mentioned on Mark's site, that is worth highlighting. Philips sold out-of-spec examples of their OC71 and OC72 transistors renumbered as OC13 and OC14, and marketed at the electronic hobbyist. They were included in some of Philips' early "Pionier" electronic component kits. Both types are listed on the radiomuseum Web site.

This image shows an extraordinary red-painted version of OC13 with a suffix H, possibly used for a specific application. In my experience, the OC13 and OC14 are rather rare, and I am seeking examples of both for my collection. If you have some for sale or exchange, please


OC14 transistor

Here is an OC14 in the standard SO-2 metal that Philips used for early 'power' types, although this is more correctly considered medium power. Oddly, radiomuseum shows an OC14 in an SO2 glass capsule, which is not correct for an OC72 as the datasheet shows. This is a mystery.


VDH logo

Returning to Van der Heem, there is a company history site, but it does not mention semiconductors. This is because VDH was primarily a manufacturer of radios, and it purchased and re-branded transistors made by other semiconductor fabricants. Some information about this can be found on Hans Hilberink's site. The link at the bottom of that page, to Gerald Tel's page, is broken: here is the correct one.

Hans Hilberink states that VDH marketed a small family of transistors, comprising OC3, OC4, and OC5. However, this is an incomplete list, as I know from an image of a Van der Heem transistor list from November 1963 that a correspondent has sent me. This reveals that VDH made types OC1 to OC6, but with multiple suffixes, and it is the suffix that determines the type of a device. In each type group, OC1 has the lowest gain, and OC6 the highest. So, there are several groups of high-frequency transistors:

  • OC1G to OC6G are 0.5 MHz PNP germanium
  • OC1H to OC6H are 3 MHz PNP germanium
  • OC1K to OC6K are 8 MHz PNP germanium
  • OC1N to OC6N are 15 MHz PNP germanium
  • OC1O to OC6O are 21 MHz PNP germanium

Then there are several groups of AF driver transistors:

  • OC1L to OC6L are PNP germanium with Vcbo = 30 volts
  • OC1L102 to OC6L102 are PNP germanium with Vcbo = 25 volts
  • OC1L104 to OC6L104 are PNP germanium with Vcbo = 20 volts

Then there are two groups of AF amplifier or driver transistors:

  • OC1LR to OC6LR are PNP germanium with Vcbo = 30 volts
  • OC1LR102 to OC6LR102 are PNP germanium with Vcbo = 25 volts

Finally there is a single group of AF output transistors:

  • OC2LP to OC5LP are PNP germanium with Vcbo = 30 volts

Oddly there is also listed an OC222 for "experimental purposes".

Note that these low numbers do NOT mean that these were the earliest OC-series devices; far from it, as evidenced by the standard encapsulation. The source of these devices could apparently be any of TeKaDe, Telefunken, RCA, Ates and others. Interestingly, members of this family were apparently competitors of the OC13 and OC14 shown above, both sets being priced relatively modestly.

Care should be taken if you find an apparent source of some Van der Heem OC types, because there exist vacuum tubes with part numbers OC2, OC3 and AC/OC4.


OC1L104 transistor

When I first came across these devices, I thought that OC1 to OC6 would form the set that is desirable from a collector's viewpoint, with the suffixes being less important. Now I know from the above that it is actually the set of all suffixes that is desirable, a harder challenge.

This image shows an OC1L104 in a TO-9 can. VDN seem to have never printed the OC prefix, probably because of space limitations.


OC2 transistor

This image shows an OC2. There is obviously a suffix, but it is hard to decipher.


OC4LR transistor

Here is an OC4LR.


OC5LR transistor

Here is a composite image of an OC5, again with the suffix LR, or possibly LP. There is a 3-digit number printed around the side, but this is not the part number suffix: it may be a date code.


OC4O transistor

And here is an oddity: I believe that it is an OC4O (that's a suffix O, not OC-forty, the latter does not exist as a germanium transistor). The vendor told me that it was supplied by Van der Heem, but it bears no indication of that, just a Philips-type code Z2 k9. The VDH transistor list only shows a crude sketch of the TO-9 can and makes no mention of alternatives.

I am seeking examples of most VDH OC types for my collection, so if you have some for sale or exchange, please


VDH 2SA12 transistor

I bought a very dilapidated Erres transistor radio type RA662 1AT because its entire transistor line up consists of Japanese transistors rebranded by Van der Heem. Hans Hilberink states that this was done across the "famous 2SA12 to 2SB77 series", mainly manufactured by Hitachi. My image shows one from my radio, a 2SA12. All the transistors in the radio look similar, although they are of several types, and all are marked 'vdHEEM'.

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