"Ian Thompson-Bell" wrote
Don Pearce wrote:
Very nearly - it was the collector back then. Were they the type with
clear gel filling that you could use as phototransistors if you
scraped the paint off?

IIRC types like the AC128 had metal cans. I think it was the good old OC71 that you could scrape the paint off to make a
photo-transitor - that is until they started filling them with opaque gunk.

That's right. AC128 were metal-canned; and the can was rather long
compared to a metal-canned BC109, for example. AC127 was the NPN
equivalent, but I don't think I ever used that. It also in later
years struct me as a bit off that the book used exclusively AC128,
which is PNP, when NPN transistors seem to be far more commonly-
used than PNP. Because PNP was the first transistor type I was
exposed to, I kinda ended up thinking that was "the normal way",
and NPN seemed odd at first.

I did have some (kinda) OC71 transistors, but they were more
modern-looking than the originals; they were called OCP71, I
think, and were blue plastic at the bottom, and then they had
the glass bulb filled with gel. They were about the same size as
AC128, and also had long bendy wires on them.

Martin
--
M.A.Poyser Tel.: 07967 110890
Manchester, U.K. http://www.livejournal.com/userinfo.bml?user=fleetie

"Don Pearce" wrote in message
...
On Sat, 3 Nov 2007 20:08:43 -0000, "Fleetie"
wrote:

"Ian Thompson-Bell" wrote
I remember when I first got into transistors in the 60s that Practical
Wireless in the UK had a series of articles for
transistor based receivers that were built on a piece of wooud. You used
wood screws with copper washers to connect things
together. worked great.

Ian

Indeed so. When I was _very_ young (maybe 9 or 10), my first
electronics book was (literally and honestly) a LADYBIRD book,
written by some Rev. (spit) someone-or-other, IIRC. Anyway, it
described various simple transistor circuits, for example,
an astable multivibrator "flip-flop", wherein 2 small MES bulbs
would flash on and off in opposition.

The circuits were suggested to be assembled on small wooden boards,
with those wood screws and screw-cap-things that go between the
screw head and the wood. I forget what they're called. Anyway,
I was lucky in that my Dad gave me a proper "modern" breadboard to use.

The transistors used in the book, and by me, were germanium PNP AC128
types.
With long bendy wires on them and a red dot to indicate the emitter
(again, IIRC). EBC.


Very nearly - it was the collector back then. Were they the type with
clear gel filling that you could use as phototransistors if you
scraped the paint off?

d

--
Pearce Consulting
http://www.pearce.uk.com

Ah, the OC71!! As a schoolboy, an OC71 was 15/- (75p) but an OCP71 was
£1/10/- when the only difference was that the OCP71 (photo sensitive
version of the OC71) didn't have the black paint. When you think that a
single transistor then was the best part of £10 today and they're a few
pence each now, that's deflation.

S.



--
http://audiopages.googlepages.com

Fleetie wrote:
"Ian Thompson-Bell" wrote
Don Pearce wrote:
Very nearly - it was the collector back then. Were they the type with
clear gel filling that you could use as phototransistors if you
scraped the paint off?
IIRC types like the AC128 had metal cans. I think it was the good old OC71 that you could scrape the paint off to make a
photo-transitor - that is until they started filling them with opaque gunk.

That's right. AC128 were metal-canned; and the can was rather long
compared to a metal-canned BC109, for example. AC127 was the NPN
equivalent, but I don't think I ever used that. It also in later
years struct me as a bit off that the book used exclusively AC128,
which is PNP, when NPN transistors seem to be far more commonly-
used than PNP. Because PNP was the first transistor type I was
exposed to, I kinda ended up thinking that was "the normal way",
and NPN seemed odd at first.

I did have some (kinda) OC71 transistors, but they were more
modern-looking than the originals; they were called OCP71, I
think, and were blue plastic at the bottom, and then they had
the glass bulb filled with gel. They were about the same size as
AC128, and also had long bendy wires on them.

Martin

Do you remember the Ediswan 'top hat' transistors. Little black things
with a ring round them that made them look like a miniature top hat.

Ian

Don Pearce wrote:

The piece of wood is actually a pretty good idea, as it allows you to
manage your grounds properly, something it is much harder to do when
everything is bolted to a chassis.


After an evenings surfing I came across this little gem:

http://www.duntemann.com/radiogallery.htm

I have just order some single sided boards and a mini drill from Maplin.

Cheers

Ian

"Serge Auckland" wrote in message
...
"Don Pearce" wrote in message
...
On Sat, 3 Nov 2007 20:08:43 -0000, "Fleetie"
wrote:

"Ian Thompson-Bell" wrote
I remember when I first got into transistors in the 60s that
Practical Wireless in the UK had a series of articles for
transistor based receivers that were built on a piece of wooud. You
used wood screws with copper washers to connect things
together. worked great.

Ian

Indeed so. When I was _very_ young (maybe 9 or 10), my first
electronics book was (literally and honestly) a LADYBIRD book,
written by some Rev. (spit) someone-or-other, IIRC. Anyway, it
described various simple transistor circuits, for example,
an astable multivibrator "flip-flop", wherein 2 small MES bulbs
would flash on and off in opposition.

The circuits were suggested to be assembled on small wooden boards,
with those wood screws and screw-cap-things that go between the
screw head and the wood. I forget what they're called. Anyway,
I was lucky in that my Dad gave me a proper "modern" breadboard to
use.

The transistors used in the book, and by me, were germanium PNP AC128
types.
With long bendy wires on them and a red dot to indicate the emitter
(again, IIRC). EBC.


Very nearly - it was the collector back then. Were they the type with
clear gel filling that you could use as phototransistors if you
scraped the paint off?

d

--
Pearce Consulting
http://www.pearce.uk.com

Ah, the OC71!! As a schoolboy, an OC71 was 15/- (75p) but an OCP71
was £1/10/- when the only difference was that the OCP71 (photo
sensitive version of the OC71) didn't have the black paint. When you
think that a single transistor then was the best part of £10 today and
they're a few pence each now, that's deflation.


Aye, them's the days - I can remember when you could take in a show,
have a couple of pints and a pie and mash supper afterwards, catch the
last bus home and still have three bob change out of half a crown!!

"Ian Thompson-Bell" wrote in message
...
Don Pearce wrote:

The piece of wood is actually a pretty good idea, as it allows you to
manage your grounds properly, something it is much harder to do when
everything is bolted to a chassis.


After an evenings surfing I came across this little gem:

http://www.duntemann.com/radiogallery.htm



Lovely link - thanks for that!

On Sun, 04 Nov 2007 20:33:02 +0000, Ian Thompson-Bell wrote:

snip

Do you remember the Ediswan 'top hat' transistors. Little black things
with a ring round them that made them look like a miniature top hat.



I think I might still have one or two of those... They were common in
early logic gear. You could also get them in a grey, unpainted metal.

How about the flat, rectangular "gold" cans? I don't know who made them,
Newmarket, I think. Green & yellow spots indicated AF and red & white
spots indicated RF.

--
Mick (Working in a M$-free zone!)
Web: http://www.nascom.info http://mixpix.batcave.net

mick wrote:
On Sun, 04 Nov 2007 20:33:02 +0000, Ian Thompson-Bell wrote:

snip
Do you remember the Ediswan 'top hat' transistors. Little black things
with a ring round them that made them look like a miniature top hat.



I think I might still have one or two of those... They were common in
early logic gear. You could also get them in a grey, unpainted metal.


I have a tin of old transistors I collected over the years and I have
one in there an XA101.

How about the flat, rectangular "gold" cans? I don't know who made them,
Newmarket, I think. Green & yellow spots indicated AF and red & white
spots indicated RF.


Weren't they the ones used by Clive Sinclair in his matchbox size radio
- Micro Alloy Transistors (MAT) IIRC?

Ian

On Sun, 4 Nov 2007 14:43:36 -0000, "Fleetie"
wrote:

I did have some (kinda) OC71 transistors, but they were more
modern-looking than the originals; they were called OCP71, I
think, and were blue plastic at the bottom, and then they had
the glass bulb filled with gel. They were about the same size as
AC128, and also had long bendy wires on them.

After they filled the OC71 with opaque gel so you couldn't scrape the
paint off and use it as a photo-transistor, they came out with the
OCP71, where the P stood for Photo. This was again filled with the
clear gel, and I think it had a small lens moulded into the side to
help gather the light.

d

--
Pearce Consulting
http://www.pearce.uk.com

"Don Pearce" wrote in message
...
On Sun, 4 Nov 2007 14:43:36 -0000, "Fleetie"
wrote:

I did have some (kinda) OC71 transistors, but they were more
modern-looking than the originals; they were called OCP71, I
think, and were blue plastic at the bottom, and then they had
the glass bulb filled with gel. They were about the same size as
AC128, and also had long bendy wires on them.

After they filled the OC71 with opaque gel so you couldn't scrape the
paint off and use it as a photo-transistor, they came out with the
OCP71, where the P stood for Photo. This was again filled with the
clear gel, and I think it had a small lens moulded into the side to
help gather the light.

d

--
Pearce Consulting
http://www.pearce.uk.com

I have an OCP71 hre, and it doesn't have a lens. I haven't used one for
years, but I recall that at the time, I used to leave the leads nice and
long so the whole transistor could be twisted for maximum sensitivity. In
fact, as the gel is translucent, light entering gets diffused, and the
sensitivity is relatively uniform so one got only a modest increase in
sensitivity rotating the device.

S.



--
http://audiopages.googlepages.com