oldest semiconductors still in use

Yup, I remember those. I may actually have some in my parts bin. ...Jim Thompson

--
| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
| Phoenix, Arizona  85048    Skype: Contacts Only  |             |
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  |
| E-mail Icon at http://www.analog-innovations.com |    1962     |
             
I love to cook with wine.     Sometimes I even put it in the food.

Absolutely, they had quite a bit of drop. I don't remember the exact numbers anymore, but I seem to remember 6-8 plates for ~200VDC.

I used to take them apart and use them for photocells ;-)

(I had lots available... my dad had a radio and TV repair shop when I was a teen.)

...Jim Thompson

--
| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
| Phoenix, Arizona  85048    Skype: Contacts Only  |             |
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  |
| E-mail Icon at http://www.analog-innovations.com |    1962     |
             
I love to cook with wine.     Sometimes I even put it in the food.

Most of the WWII radar first mixer diodes were silicon. They even had some GaAs point-contact diodes back then.

John

Yep, I missed that. NVOS...

--

Jeff

some of the oldest still in production

t 1965 was not only silicon transistors, but Fairchild planar silicon transistors - a real step forward. It's most unlikely that MIT would have used germanium transistors in the LINC computer. Jim Thompson may know - he was at MIT a bit before then and should know which transistors were favoured at MIT at the time.

-- Bill Sloman, Nijmegen

The forward drop was around 20% for a new stack, and the drop went up as they aged.

Early color TVs and some small B&W sets used a long tubular stack of Selenium diodes in the focus or HV section.

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What are you looking for, all the way down here?

It was a common video detector.

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What are you looking for, all the way down here?

Sorry, I was thinking of the 1N82 UHF mixer diode used in solid state and some tube UHF TV tuners.

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What are you looking for, all the way down here?

They certainly didn't use Selenium rectifiers there. The really old TV's had vacuum rectifiers, and then they had to have lead-glass envelopes, as the rectifier was a strong source of X-rays. That would be mostly on the early color sets, as the HV was higher.

Jon

some of the oldest still in production

But, the LINC was built using off the shelf DEC "system building block" cards, roughly 5 x 7" boards of one-sided paper-phenolic with a folded aluminum stiffener wrapped around the edge of the board, and an Elco single-row connector to plug into the card cage connectors. So, the design of these OTS modules was older by quite a few years, and likely the same units as used on the PDP-1, PDP-5 and similar computers from the very beginning of DEC.

So, that's why I think they likely were Germanium. DEC later made the early PDP-8's with much smaller G-10 glass-epoxy boards and discrete transistors, before adopting ICs in the later 1960's. I'm sure those were Silicon transistors.

Jon

On a sunny day (Fri, 07 Jan 2011 16:08:55 -0600) it happened Jon Elson wrote in :

Right. The firts? Philips color set, the K6 chassis

had a PC100 parallel 25 kV HV stabiliser triode. You could call that a Roentgen tube. The HV recifier was a GY501

Of course I had an early model :-) The mains rectifiers were just si diodes. About 1967 Color started here in 1967 with PAL.

The first BW TV that I had was a Philips 'hondehok', Dutch for 'dog house':

Those used vacumm tubes for mains rectification and HV. A link to the diagrams is also on that site. Magnetically focussed CRT, ion trap ....

Oh I could tell stories about that.

BZZZZZTTT!!! You are wrong.

Here is a surpus one rated to 20 KV:

The lead glass tubes were the HV regulators. Like the 6BK4 family.

--
You can't fix stupid. You can't even put a band-aid on it, because it's
Teflon coated.

=20

Double checked to be sure, the 2n107 is an audio device. The 2n170 NPN was an RF device. I had access to these as a kid; also 2n207 and 2n270, later 2n414.=20

The 2n109 appears to have been a higher grade (more reliable) audio amplifier.

Your data is way too new. Back in the day, the 2N107 was the 'RF' model. 'RF' is a moving target!

Cheers

Phil Hobbs

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Dr Philip C D Hobbs
Principal
ElectroOptical Innovations
55 Orchard Rd
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email: hobbs (atsign) electrooptical (period) net
http://electrooptical.net

Yesss..moving target. Remember the early transistor radios that had IF stages, that they used the same neutralization scheme used in tubes for extending frequency capability; 455KC was such a HF that it was a bit dicey..

And it was "low noise", too.

John

Mark

I

amps.

NPN

2n270,

It sure looked like the period data sheets i remember. Then again two or three years then would have easily have made that difference. IIRC f(t) for the 2n107 was under 1 MHz. Of course that could have improved over a couple of years then also.