More Tubes/Valves...

[Steve Anderson]

Found today...

https://www.youtube.com/watch?v=TYRkkA0vDNI

Steve A.

[acl]

https://www.nutsvolts.com/magazine/arti ... TXX_-7W_Qs

[Steve Anderson]

Another novel 1" CRT design. It seems the goal was to miniaturise the unit which makes me wonder why tubes/valves were used. It doesn't really matter as the goal was achieved! There is also today the novelty factor.

Now I've seen the original 1960 Popular Electronics article, it only uses two (or three) tubes/valves in addition to the 1CP1 CRT, so even 'transistorizing' it would make little difference.

Steve A.

A conceptually similar device was made by Cossor in the UK, the 1039M, though somewhat more complex and a larger screen...

[Steve Anderson]

...another similar version made by GEC...I love the "Dog-Bone" knobs...

GEC Miniscope advert.jpg (53.33 KiB) Viewed 3305 times

GEC Miniscope front.jpg (19.5 KiB) Viewed 3305 times

DogBone 1.jpg (5.04 KiB) Viewed 3304 times

[Dave Moll]

It seems the goal was to miniaturise the unit which makes me wonder why tubes/valves were used.

Surely, in 1954 it would have been surprising (and probably expensive) to use those unproven solid-state alternatives.

[Steve Anderson]

Surely, in 1954 it would have been surprising (and probably expensive) to use those unproven solid-state alternatives.

Yes, agreed, the date hadn't quite registered in my empty skull...at that sort of time an 0C71 was the same as a blue-collar's weekly wage...

How many here know what an 0C71 is? Or can even remember? I can. In a word, awful...stick with your BC107....even they raise a wry smile from me...

Steve A.

ADJECTIVE [usually ADJECTIVE noun]
If someone has a wry expression, it shows that they find a bad situation or a change in a situation slightly amusing. [...], also consider "Incongruous"...in todays semiconductor perspective...

Anyway, the thing did what was expected, and that's good enough for me....

[acl]

Steve,

I can remember the OC71. Doug Pitt had a story whereby if you put an OC71 in the spin drier to force the innards to the legs of the device you got yourself an OCP71 phototransistor. Can't verify this myself. In the radio club he used to buy a batch of suspect top hat transistors and because these were of unknown condition we had to test them all individually so we could make our radios, Perhaps Stan could confirm this.

Regards Chris Lewis

[Klaas Robers]

I used the OC71 quite frequently in the beginning of the sixties. And indeed, if you remove the black paint from the glass enclosure, you get a photo transistor. In the end of the 50's I used as well the OC13. It was an OC71 with a too low amplification factor. They were also cheaper. This was how our company Philips sold his scrap of germanium transistors. I still should have several of these transistors.

During my time at Delft University the silicium transistors came in use. That was from 1962 to 1969. Then I never used those Germanium transistors any more. That is also the reason that I have still quite some of them. In the beginning they all came from the USA, Motorola and so on.

And then at the end of the sixties Philips came with the BC107 family. It took them quite some time to master that process. Then came also the change from a negative supply voltage (PNP-transistors) to positive supply for NPN-transistors. I never understood why it is easier to make PNP-transistors in the Germanium process and NPN-transistors in the silicium process. Yes, there were NPN-transistors in Germanium, but just a few, and they were more expensive than their PNP-brothers.

[Steve Anderson]

It would be quite a challenge to build something using all Germanium transistors these days. You would soon realise their limitations! No, I'm not volunteering! Tubes/valves any day!

Steve A.

I recall using AC126s and AF117s (both Germanium, and both PNP) as part of an electronics 'laboratory' for youngsters, made by Philips in the 60s....

[Klaas Robers]

This opens my heart!

As Philips we did quite some remarkable things in the past to encourage youngsters to step into the world of electronics. At that time I made that step already. Especially the booklets that came along with them were top!

It is good to remind that it were ham-radio amateurs that initiated and carried this devellopments. I have known quite some of them.

[Steve Anderson]

I had one of these Philips 'Electronic Engineer' kits (I suppose you'd call them) in the 60s. It switched my interest from chemistry to electronics.

Here's how an AM MW/LW radio was assembled...

Note that the supply line at the top is negative as a result of using Germanium PNP transistors...the two electrolytic caps in the centre point to this...

Steve A.

Philips EE-20 Electronic Engineer Construction Box-04 - Reflex Radio Receiver.jpg (86.91 KiB) Viewed 3213 times

[Dave Moll]

I too had one of these kits. From the pictures and descriptions, I'm pretty sure it was the EE8.

Unfortunately, like so many other things from my childhood, it is long gone, and although I've acquired a small selection of electronic kits in recent years, none of these Philips ones with their characteristic "spring and hairclip" component fixing posts.

[Harry Dalek]

We had Tandy electronics for a while in the 70s and when i was 15 i got hooked on these Kits pretty much twisting the wires together, I like the short wave radio most out of the kits .

[Viewmaster]

https://www.ebay.co.uk/itm/134651068541

[Steve Anderson]

Good find Albert! Good to see you 'looking in' occasionally...how's the astronomy thing? BTW, need an accurate GPS driven Sidereal clock? You can buy them, at a price, so I built mine...there are other versions on the 'net too...

Steve A.