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

On Sun, 13 May 2007 23:31:10 +1000, "Phil Allison"


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.

On Mon, 14 May 2007 14:12:17 +1000, Bob Parker


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

On Mon, 14 May 2007 05:29:16 GMT, "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.

    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.

     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!

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"



** 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