Oldest plugpak still in use?

"Phil Allison"

I guess any old mains powered device that runs low power DC circuitry inside would be the equivalent. I dont think plug packs existed before the late sixties.

Cheers, Dean. ( well go on Phil....abuse me )

"Deano" "Phil Allison"

** Not really -

as they are not all miniature, made to double insulation requirements and type approved for human safety like " plugpaks" are.

** My impression too.

The one I allude to is the first I ever owned.

....... Phil

When did the first encapsulated solid state rectifiers appear, that's probably what was needed. I recall in the mid 60s it was still 5Y3 valves and copper oxide stacks.

"Bruce Varley"

** The introduction of class 2 or double insulation was the main precursor.

Silicon diodes with 1 amp or more capacity date from the early 60s.

Eg the OA210.

........ Phil

I doubt that there would have been many low power/low voltage consumer devices around prior to the 60's, so therefore not much of a market for a plugpack. The few that were would use batteries, and/or have an internal transformer.

Quite possible too that the transformers then were less efficient and therefore had to be much heavier, larger and run hotter to supply the same VA as a modern ironcore unit, which would limit the possible VA rating that you could fit inside a plugpack without making it too large or heavy to be of practical use.

Things suddenly got smaller, lighter and more portable and there was no room left for a transformer inside, and the plugpack soon arrived. As in Phil's example, it would be hard to fit a transformer inside a pocket calculator, and even if you could, the calculator would probably be pulled off the table by the weight of even the lightest legally allowable mains cord ;)

The first plugpack I ever saw was about 1974, for some reason my parents bought a "sheen" LED display calculator 9v battery powered but it also came with a plugpack, I cant remember seeing any before that. Soon after that, they started appearing everywhere, and most battery operated devices would at least have a "DC IN" socket to accept a plugpack.

The oldest I have would be from late 1970's, would be a tandy 9v unit, though I havent used it in many years. I would be confident that it still works perfectly though.

"kreed"

** What nonsense.

** A 9 volt radio "battery eliminator" only needs to have 2 watts output - so a tiny filament transformer does the job.

They were around in the early 1960s, but not in the form of a plug pack. I recall seeing such eliminators on sale, in white plastic boxes with two wire AC leads and a 9 volt snap for output.

Made by Ferguson Transformers and others.

Not double insulated, as that come along later.

....... Phil

**Not me. I bought one of those calcs. $104.00 as I recall. The damned calculator fell apart, but the charger is probably still OK. As I recall, it also has a 3.5mm jack plug on the end? Dumb. And cheap. Still and all, it was a much cheaper calculator than the HP. I'll bet the HPs didn't fall apart though.

--
Trevor Wilson
www.rageaudio.com.au

"Trevor Wilson"

** Nothing just "falls apart" - fools damage them.

TW is full of shit as usual.

My EMONA LED scientific calc was faultless for 8 or 9 years, only dying when the internal Ni-Cds leaked.

I got a TI LCD scientific calc - total lemon, the keypad was a diaster.

Finally got onto Casio - no complaints with them.

....... Phil

that's

precursor.

Phil,

OA210 had max forward current of 500mA (averaging time 50mSec). The Miniwatt catalog I posted some time ago on abse has the details.

I can still remember buying my first EM408 diode from Radio Despatch Service ...

"Bob Parker"

** Bought two there in 1969 - for my 1966, 3 inch 2 MHz CRO.

So the part must date from pre '66.

...... Phil

That sounds about right. I think STC used to advertise them in "EA" magazine. If I had any going back that far I'd have a look.

60s.

Despatch

The EM40x series from STC came out around mid to late 60's at the same time as the 1N400x. Between the OA210 and the EM40x series the smaller and much more user friendly (compared to the OA210) 1N3254 (DO-26) came out. This was rated 400v @ 750mA and although it had a metal case it was insulated with a clear pvc jacket. It made for much quicker and tidier installation on all those LME relay coil tags :-)

"Ross Herbert" wrote

The EM40x series from STC came out around mid to late 60's at the same time as the 1N400x. Between the OA210 and the EM40x series the smaller and much more user friendly (compared to the OA210) 1N3254 (DO-26) came out. This was rated 400v @ 750mA and although it had a metal case it was insulated with a clear pvc jacket.

****What was the Ducon epoxy cased blue power diode?400 V,500mA,1N1763 springs to mind! Available in 1964.

Brian G

same

smaller

case

V,500mA,1N1763

1N1763 was similar to the OA210 in physical shape and characteristics. Another type used in place of the OA210/1N1763 was the Texas Instruments 1S103 (circa 1962 - I have some still). It was in a similar top-hat style to these two but it was rated at 400V, 750mA (same as 1N3254) and was also available in a clear shrink pvc jacket like the 1N3254.

**I dunno what mine was. It had a yellow plastic thing in the centre. I also purchased it from Radio Dustpatch. I bought it when I was 14 years old (ca. 1967) for the family's portable (solid state) TV set. The old man took it to the local TV guy for service and was horrified when they quoted him $150.00 to fix it. He asked if I'd have a go. Fortunately, in those days, there was a schematic with the set. It worked OK on 12 Volts, but not on 240VAC. I reasoned that it was either the tranny or the bridge. I used my meter (Sanwa) that the old man gave me for Christmas to test the tranny. All looked OK, so I hopped a train to Central and bought a few diodes, soldered them in and the thing has worked ever since. The old man was pretty chuffed and figured the multimeter was a bloody good investment.

--
Trevor Wilson
www.rageaudio.com.au

A bright yellow plastic bullet-shaped thing? I remember those .... Not bad fault-finding for a 14 year old. :)

**That's the one! BTW I might have been 15. I recall measuring one diode (I purchased 4, but only required 2) and I noted that it was leaky.

--
Trevor Wilson
www.rageaudio.com.au

I vaguely remember finding a leaky one, and definitely remember one which had a loose lead. Not yer top quality power diodes, that's for sure!