TO-92 package

markings:

"650"
"B24"

I've got dozens of them. Wondering if I can use them for anything.

--
Paul Hovnanian
------------------------------------------------------------------
How do I set a laser printer to stun?

On a sunny day (Wed, 30 Jan 2013 20:16:28 -0800) it happened "Paul Hovnanian
P.E." wrote in
:

TO-92 package

markings:

"650"
"B24"

I've got dozens of them. Wondering if I can use them for anything.

Why not measure one?
PNP-NPN?
Beta
Build a curve tracer (Vce breakdown).

:-)

Oh, Ft..

"Jan Panteltje" wrote in message
...
On a sunny day (Wed, 30 Jan 2013 20:16:28 -0800) it happened "Paul
Hovnanian
P.E." wrote in
:

TO-92 package

markings:

"650"
"B24"

I've got dozens of them. Wondering if I can use them for anything.

Why not measure one?
PNP-NPN?
Beta
Build a curve tracer (Vce breakdown).

:-)

Oh, Ft..


Quick NPN PNP determination with a meter in diode test mode. Allow for base
in center or to one side.
Fets show a body diode in reverse and touching the meter between G-S will
store enough charge to measure some forward conduction D-S. Grab the leads
with your fingers to drain the charge and D-S should look open.
Even nicer if your meter has a transistor tester function that gives a
figure of merit on beta. Nothing beats a curve tracer though. I've got a 30
year old sencore one.

Hard to say if it's a house number but looks like it. When you buy enough or
pay enough, vendors will private label. Saw that all the time when I worked
with mil-spec stuff.

On Thu, 31 Jan 2013 09:07:08 GMT, Jan Panteltje
wrote:
On a sunny day (Wed, 30 Jan 2013 20:16:28 -0800) it happened "Paul
Hovnanian P.E." wrote in
:

TO-92 package markings:

"650"
"B24"

I've got dozens of them. Wondering if I can use them for anything.

Why not measure one?
PNP-NPN?
Beta
Build a curve tracer (Vce breakdown).

Which begs ( for ) the question: Has anyone attempted to develop a
method for identifying components simply from their characeristics?

Plug a BJT into a test socket, drive the pins, measure the traces,
feed the results into a database, and out pops...

"It's a 2N2222A, dummy!"

Hm... is there a way of testing ( say ) a BJT's BVce "gently", that
is, so that it doesn't _stay_ broken down?

Jes' curious.


Frank McKenney
--
Nearly every feature of the American system of manufacturing, from
the elements of the new textile machinery to the concept of
interchangeable parts, had actually been conceived earlier by
Europeans. But while a few Europeans could see the possibilities,
their communities kept them powerless to give their ideas a free
trial. Too many had a stake in the older ways. Industrial progress
in Europe required extraordinary courage to break the prevailing
pattern; in America it required a willingness to try the obvious.
American genius was less for invention or discovery than for
experiment.
-- Daniel J. Boorstin / The Americans: The National Experience
--
Frank McKenney, McKenney Associates
Richmond, Virginia / (804) 320-4887
Munged E-mail: frank uscore mckenney aatt mindspring ddoott com

On a sunny day (Thu, 31 Jan 2013 13:00:32 -0600) it happened Frnak McKenney
wrote in
:

Which begs ( for ) the question: Has anyone attempted to develop a
method for identifying components simply from their characeristics?

Plug a BJT into a test socket, drive the pins, measure the traces,
feed the results into a database, and out pops...

"It's a 2N2222A, dummy!"

Hm... is there a way of testing ( say ) a BJT's BVce "gently", that
is, so that it doesn't _stay_ broken down?

Jes' curious.


Ferry Lon Taim AGOH I designed and build a transistor curve tracer.
Was just not much work, and boss wanted one.
To keep dissipation in limits you need to use low impulse duty cycle.
It could find NPN or PNP automatically.
No micros at that time, just relays and logic,
output to a normal xy scope.

I am sure with a PC these days you could look up things in a database,
and have a better display.

On Thu, 31 Jan 2013 13:00:32 -0600, Frnak McKenney wrote:

Hm... is there a way of testing ( say ) a BJT's BVce "gently", that is,
so that it doesn't _stay_ broken down?

Frank McKenney

Sure, a real BJT (perhaps excepting some RF exotica) can be pushed beyond
BVce so long as current is kept low. You can see this quite nicely on a
curve tracer if you have access to one. I haven't heard of any problems
with devices "abused" in this way, not even MTBF.

BVeb is another matter. Breaking down EB junctions reduces beta,
increasing noise and may lead to shortened MTBF. Supposedly forward
biasing "anneals", but I don't know if it's completely reversible.
IIRC its a function of total-reverse-charge, so you should be able to go
into a very limited breakdown for a short time without "significant"
damage - perfectly sufficient for a tester.

-F

"Frnak McKenney" wrote in message
m...
On Thu, 31 Jan 2013 09:07:08 GMT, Jan Panteltje
wrote:
On a sunny day (Wed, 30 Jan 2013 20:16:28 -0800) it happened "Paul
Hovnanian P.E." wrote in
:

TO-92 package markings:

"650"
"B24"

I've got dozens of them. Wondering if I can use them for anything.

Why not measure one?
PNP-NPN?
Beta
Build a curve tracer (Vce breakdown).

Which begs ( for ) the question: Has anyone attempted to develop a
method for identifying components simply from their characeristics?

Apparently Peak-Atlas are marketing a (massively) upgraded version of their
3-terminal component analyser, it has a USB port for connection to a PC (I
think it may actually do curve tracing).

The original version I bought about a decade ago will at least tell you if a
device is transistor, MOSFET or just a pair of diodes - anything more
complex and it'll just report "unrecognised or faulty component".

Apparently Peak-Atlas are marketing a (massively) upgraded version of their
3-terminal component analyser, it has a USB port for connection to a PC (I
think it may actually do curve tracing).

http://www.anatekcorp.com/atlasdca75.htm

Frank Miles wrote in message
...
On Thu, 31 Jan 2013 13:00:32 -0600, Frnak McKenney wrote:

Hm... is there a way of testing ( say ) a BJT's BVce "gently", that is,
so that it doesn't _stay_ broken down?

Frank McKenney

Sure, a real BJT (perhaps excepting some RF exotica) can be pushed beyond
BVce so long as current is kept low. You can see this quite nicely on a
curve tracer if you have access to one. I haven't heard of any problems
with devices "abused" in this way, not even MTBF.

BVeb is another matter. Breaking down EB junctions reduces beta,
increasing noise and may lead to shortened MTBF. Supposedly forward
biasing "anneals", but I don't know if it's completely reversible.
IIRC its a function of total-reverse-charge, so you should be able to go
into a very limited breakdown for a short time without "significant"
damage - perfectly sufficient for a tester.

-F


Also how to tell you have a "digital" transistor in front of you?

On a sunny day (Fri, 1 Feb 2013 10:42:07 -0000) it happened "N_Cook"
wrote in :

Frank Miles wrote in message
...
On Thu, 31 Jan 2013 13:00:32 -0600, Frnak McKenney wrote:

Hm... is there a way of testing ( say ) a BJT's BVce "gently", that is,
so that it doesn't _stay_ broken down?

Frank McKenney

Sure, a real BJT (perhaps excepting some RF exotica) can be pushed beyond
BVce so long as current is kept low. You can see this quite nicely on a
curve tracer if you have access to one. I haven't heard of any problems
with devices "abused" in this way, not even MTBF.

BVeb is another matter. Breaking down EB junctions reduces beta,
increasing noise and may lead to shortened MTBF. Supposedly forward
biasing "anneals", but I don't know if it's completely reversible.
IIRC its a function of total-reverse-charge, so you should be able to go
into a very limited breakdown for a short time without "significant"
damage - perfectly sufficient for a tester.

-F


Also how to tell you have a "digital" transistor in front of you?

WTF is a 'digital transistor'?????????????????

Jan Panteltje wrote in message
...
On a sunny day (Fri, 1 Feb 2013 10:42:07 -0000) it happened "N_Cook"
wrote in :

Frank Miles wrote in message
...
On Thu, 31 Jan 2013 13:00:32 -0600, Frnak McKenney wrote:

Hm... is there a way of testing ( say ) a BJT's BVce "gently", that
is,
so that it doesn't _stay_ broken down?

Frank McKenney

Sure, a real BJT (perhaps excepting some RF exotica) can be pushed
beyond
BVce so long as current is kept low. You can see this quite nicely on
a
curve tracer if you have access to one. I haven't heard of any
problems
with devices "abused" in this way, not even MTBF.

BVeb is another matter. Breaking down EB junctions reduces beta,
increasing noise and may lead to shortened MTBF. Supposedly forward
biasing "anneals", but I don't know if it's completely reversible.
IIRC its a function of total-reverse-charge, so you should be able to
go
into a very limited breakdown for a short time without "significant"
damage - perfectly sufficient for a tester.

-F


Also how to tell you have a "digital" transistor in front of you?

WTF is a 'digital transistor'?????????????????


Exactly, thats how they are referred to in UK listings, and without any " "s

On a sunny day (Fri, 1 Feb 2013 11:36:40 -0000) it happened "N_Cook"
wrote in :

Also how to tell you have a "digital" transistor in front of you?

WTF is a 'digital transistor'?????????????????


Exactly, thats how they are referred to in UK listings, and without any " "s

Well, cannot help you there,
but a transistor is a transistor, no matter what is written on - or about it.
A rose is a rose by any other name (to keep it UK related).

On Fri, 01 Feb 2013 11:04:10 GMT, the renowned Jan Panteltje
wrote:

On a sunny day (Fri, 1 Feb 2013 10:42:07 -0000) it happened "N_Cook"
wrote in :

Frank Miles wrote in message
...
On Thu, 31 Jan 2013 13:00:32 -0600, Frnak McKenney wrote:

Hm... is there a way of testing ( say ) a BJT's BVce "gently", that is,
so that it doesn't _stay_ broken down?

Frank McKenney

Sure, a real BJT (perhaps excepting some RF exotica) can be pushed beyond
BVce so long as current is kept low. You can see this quite nicely on a
curve tracer if you have access to one. I haven't heard of any problems
with devices "abused" in this way, not even MTBF.

BVeb is another matter. Breaking down EB junctions reduces beta,
increasing noise and may lead to shortened MTBF. Supposedly forward
biasing "anneals", but I don't know if it's completely reversible.
IIRC its a function of total-reverse-charge, so you should be able to go
into a very limited breakdown for a short time without "significant"
damage - perfectly sufficient for a tester.

-F


Also how to tell you have a "digital" transistor in front of you?

WTF is a 'digital transistor'?????????????????

Transistor with base resistor(s) built in. Eg.
http://www.nxp.com/documents/data_sh...TC144E_SER.pdf


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

On a sunny day (Fri, 01 Feb 2013 08:06:21 -0500) it happened Spehro Pefhany
wrote in
:

On Fri, 01 Feb 2013 11:04:10 GMT, the renowned Jan Panteltje
wrote:

On a sunny day (Fri, 1 Feb 2013 10:42:07 -0000) it happened "N_Cook"
wrote in :

Frank Miles wrote in message
...
On Thu, 31 Jan 2013 13:00:32 -0600, Frnak McKenney wrote:

Hm... is there a way of testing ( say ) a BJT's BVce "gently", that is,
so that it doesn't _stay_ broken down?

Frank McKenney

Sure, a real BJT (perhaps excepting some RF exotica) can be pushed beyond
BVce so long as current is kept low. You can see this quite nicely on a
curve tracer if you have access to one. I haven't heard of any problems
with devices "abused" in this way, not even MTBF.

BVeb is another matter. Breaking down EB junctions reduces beta,
increasing noise and may lead to shortened MTBF. Supposedly forward
biasing "anneals", but I don't know if it's completely reversible.
IIRC its a function of total-reverse-charge, so you should be able to go
into a very limited breakdown for a short time without "significant"
damage - perfectly sufficient for a tester.

-F


Also how to tell you have a "digital" transistor in front of you?

WTF is a 'digital transistor'?????????????????

Transistor with base resistor(s) built in. Eg.
http://www.nxp.com/documents/data_sh...TC144E_SER.pdf

OK, but that is actually an integrated circuit.
Just mis-labeled 'transistor'.
:-)

You can still test those with a multimeter and lab supply.
On a curve tracer for transistors it would look strange I'd guess.

If you see reverse conductance in base emitter junction with an Ohm meter,
that would be an indictation.
If that resistance was the same both ways, more so.

I'd probably toss it :-)

On a sunny day (Fri, 01 Feb 2013 13:17:42 GMT) it happened Jan Panteltje
wrote in :


OK, but that is actually an integrated circuit.
Just mis-labeled 'transistor'.
:-)

PS,
some of us here will remember RTL logic.
That was pretty much like that, but more transistors to make gates, and output R too.
Integrated circuits.

"Jan Panteltje" wrote in message
...
On a sunny day (Fri, 1 Feb 2013 10:42:07 -0000) it happened "N_Cook"
wrote in :

Frank Miles wrote in message
...
On Thu, 31 Jan 2013 13:00:32 -0600, Frnak McKenney wrote:

Hm... is there a way of testing ( say ) a BJT's BVce "gently", that
is,
so that it doesn't _stay_ broken down?

Frank McKenney

Sure, a real BJT (perhaps excepting some RF exotica) can be pushed
beyond
BVce so long as current is kept low. You can see this quite nicely on a
curve tracer if you have access to one. I haven't heard of any problems
with devices "abused" in this way, not even MTBF.

BVeb is another matter. Breaking down EB junctions reduces beta,
increasing noise and may lead to shortened MTBF. Supposedly forward
biasing "anneals", but I don't know if it's completely reversible.
IIRC its a function of total-reverse-charge, so you should be able to go
into a very limited breakdown for a short time without "significant"
damage - perfectly sufficient for a tester.

-F


Also how to tell you have a "digital" transistor in front of you?

WTF is a 'digital transistor'?????????????????

Its a regular transistor with built in resistors - some are exactly
described that way rather than "digital", the most common arrangement is a
B-E bleed resistor + a base series current limiting resistor.

They are often used directly as an open collector inverter gate.

"Jan Panteltje" wrote in message
...
On a sunny day (Fri, 01 Feb 2013 13:17:42 GMT) it happened Jan Panteltje
wrote in :


OK, but that is actually an integrated circuit.
Just mis-labeled 'transistor'.
:-)

PS,
some of us here will remember RTL logic.
That was pretty much like that, but more transistors to make gates, and
output R too.
Integrated circuits.


My first job was component level fault finding on Olympia desk calculators,
they contained about 4 boards of DTL - a 5th board at the back was
critically sensitive MOS shift registers. The boards were about the same
area as S100, but wider & not so high, the front board had about a dozen
nixie tubes.

I must've just missed out on RTL by not all that long, it was only just
becoming scarce in component catalogues of the day.

"notme" wrote in message
...
Apparently Peak-Atlas are marketing a (massively) upgraded version of
their
3-terminal component analyser, it has a USB port for connection to a PC
(I
think it may actually do curve tracing).

http://www.anatekcorp.com/atlasdca75.htm

Any idea what $169 is converted to GBP?

Ian Field Inscribed thus:



"notme" wrote in message
...
Apparently Peak-Atlas are marketing a (massively) upgraded version
of their
3-terminal component analyser, it has a USB port for connection to a
PC (I
think it may actually do curve tracing).

http://www.anatekcorp.com/atlasdca75.htm

Any idea what $169 is converted to GBP?

Just over £105.00p

--
Best Regards:
Baron.

On a sunny day (Fri, 1 Feb 2013 16:46:09 -0000) it happened "Ian Field"
wrote in :



"Jan Panteltje" wrote in message
...
On a sunny day (Fri, 1 Feb 2013 10:42:07 -0000) it happened "N_Cook"
wrote in :

Frank Miles wrote in message
...
On Thu, 31 Jan 2013 13:00:32 -0600, Frnak McKenney wrote:

Hm... is there a way of testing ( say ) a BJT's BVce "gently", that
is,
so that it doesn't _stay_ broken down?

Frank McKenney

Sure, a real BJT (perhaps excepting some RF exotica) can be pushed
beyond
BVce so long as current is kept low. You can see this quite nicely on a
curve tracer if you have access to one. I haven't heard of any problems
with devices "abused" in this way, not even MTBF.

BVeb is another matter. Breaking down EB junctions reduces beta,
increasing noise and may lead to shortened MTBF. Supposedly forward
biasing "anneals", but I don't know if it's completely reversible.
IIRC its a function of total-reverse-charge, so you should be able to go
into a very limited breakdown for a short time without "significant"
damage - perfectly sufficient for a tester.

-F


Also how to tell you have a "digital" transistor in front of you?

WTF is a 'digital transistor'?????????????????

Its a regular transistor with built in resistors - some are exactly
described that way rather than "digital", the most common arrangement is a
B-E bleed resistor + a base series current limiting resistor.

They are often used directly as an open collector inverter gate.

Thanks.
Spehro even gave a link to a datasheet.

On a sunny day (Fri, 1 Feb 2013 16:55:24 -0000) it happened "Ian Field"
wrote in :



"Jan Panteltje" wrote in message
...
On a sunny day (Fri, 01 Feb 2013 13:17:42 GMT) it happened Jan Panteltje
wrote in :


OK, but that is actually an integrated circuit.
Just mis-labeled 'transistor'.
:-)

PS,
some of us here will remember RTL logic.
That was pretty much like that, but more transistors to make gates, and
output R too.
Integrated circuits.


My first job was component level fault finding on Olympia desk calculators,
they contained about 4 boards of DTL - a 5th board at the back was
critically sensitive MOS shift registers. The boards were about the same
area as S100, but wider & not so high, the front board had about a dozen
nixie tubes.

I must've just missed out on RTL by not all that long, it was only just
becoming scarce in component catalogues of the day.

DTL was better, it was faster too IIRC.

"Jan Panteltje" wrote in message
...
On a sunny day (Fri, 1 Feb 2013 16:55:24 -0000) it happened "Ian Field"
wrote in
:



"Jan Panteltje" wrote in message
...
On a sunny day (Fri, 01 Feb 2013 13:17:42 GMT) it happened Jan Panteltje
wrote in :


OK, but that is actually an integrated circuit.
Just mis-labeled 'transistor'.
:-)

PS,
some of us here will remember RTL logic.
That was pretty much like that, but more transistors to make gates, and
output R too.
Integrated circuits.


My first job was component level fault finding on Olympia desk
calculators,
they contained about 4 boards of DTL - a 5th board at the back was
critically sensitive MOS shift registers. The boards were about the same
area as S100, but wider & not so high, the front board had about a dozen
nixie tubes.

I must've just missed out on RTL by not all that long, it was only just
becoming scarce in component catalogues of the day.

DTL was better, it was faster too IIRC.


IIRC the crystal was 3MHz, I assume they'd run the MOS shift registers as
fast as they could get away with - and that would probably be what set the
upper limit.

One shift register recirculated the product of calculations past a row of
TTL 7475s which latched the "correct answer" every time it whizzed past.

I think the BCD to Nixie decoder/drivers were also TTL, the bulk of the
chips (over 200) were DTL.

On a sunny day (Fri, 1 Feb 2013 18:40:50 -0000) it happened "Ian Field"
wrote in :



"Jan Panteltje" wrote in message
...
On a sunny day (Fri, 1 Feb 2013 16:55:24 -0000) it happened "Ian Field"
wrote in
:



"Jan Panteltje" wrote in message
...
On a sunny day (Fri, 01 Feb 2013 13:17:42 GMT) it happened Jan Panteltje
wrote in :


OK, but that is actually an integrated circuit.
Just mis-labeled 'transistor'.
:-)

PS,
some of us here will remember RTL logic.
That was pretty much like that, but more transistors to make gates, and
output R too.
Integrated circuits.


My first job was component level fault finding on Olympia desk
calculators,
they contained about 4 boards of DTL - a 5th board at the back was
critically sensitive MOS shift registers. The boards were about the same
area as S100, but wider & not so high, the front board had about a dozen
nixie tubes.

I must've just missed out on RTL by not all that long, it was only just
becoming scarce in component catalogues of the day.

DTL was better, it was faster too IIRC.


IIRC the crystal was 3MHz, I assume they'd run the MOS shift registers as
fast as they could get away with - and that would probably be what set the
upper limit.

One shift register recirculated the product of calculations past a row of
TTL 7475s which latched the "correct answer" every time it whizzed past.

I think the BCD to Nixie decoder/drivers were also TTL, the bulk of the
chips (over 200) were DTL.

In the late sixties or maybe very early seventies I build a frequency counter
with 4790 decade counters, and 7475 latches,
cannot remember the number of the nixie driver chips, also TTL.
It had a 100 kHz crystal as reference, 5 digits, counted up to about 30 MHz,
as that was the maximum where the TTL would still work.

In article ,
Jan Panteltje wrote:

Also how to tell you have a "digital" transistor in front of you?

WTF is a 'digital transistor'?????????????????

This is a fairly common term for a composite device... it's packaged
like an ordinary transistor (SMT or TO-92), but includes a
current-limiting resistor in the base lead (and often a base-to-
emitter pulldown).

It's used as a power-switching device, driven directly from a logic
signal (often a microcontroller pin).

Think of it as "just about the simplest sort of 'integrated circuit'
you can imagine". It's even simpler than the tiny little "simple glue
logic" chips you can buy these days (e.g. a NOT gate in a four-pin SMT
package, or a NAND in a 5-pin).

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

On a sunny day (Fri, 1 Feb 2013 11:13:45 -0800) it happened
(Dave Platt) wrote in :

In article ,
Jan Panteltje wrote:

Also how to tell you have a "digital" transistor in front of you?

WTF is a 'digital transistor'?????????????????

This is a fairly common term for a composite device... it's packaged
like an ordinary transistor (SMT or TO-92), but includes a
current-limiting resistor in the base lead (and often a base-to-
emitter pulldown).

It's used as a power-switching device, driven directly from a logic
signal (often a microcontroller pin).

Think of it as "just about the simplest sort of 'integrated circuit'
you can imagine". It's even simpler than the tiny little "simple glue
logic" chips you can buy these days (e.g. a NOT gate in a four-pin SMT
package, or a NAND in a 5-pin).

For a very short moment I did think 'unijunction transistor',
at least those are either on or off, but then I dismiossed that on context.
I bought a bunch of 2n4246 UJTs last year from ebay.
Make nice oscillators.

"Jan Panteltje" wrote in message
...
On a sunny day (Fri, 1 Feb 2013 18:40:50 -0000) it happened "Ian Field"
wrote in :



"Jan Panteltje" wrote in message
...
On a sunny day (Fri, 1 Feb 2013 16:55:24 -0000) it happened "Ian Field"
wrote in
:



"Jan Panteltje" wrote in message
...
On a sunny day (Fri, 01 Feb 2013 13:17:42 GMT) it happened Jan
Panteltje
wrote in :


OK, but that is actually an integrated circuit.
Just mis-labeled 'transistor'.
:-)

PS,
some of us here will remember RTL logic.
That was pretty much like that, but more transistors to make gates,
and
output R too.
Integrated circuits.


My first job was component level fault finding on Olympia desk
calculators,
they contained about 4 boards of DTL - a 5th board at the back was
critically sensitive MOS shift registers. The boards were about the same
area as S100, but wider & not so high, the front board had about a dozen
nixie tubes.

I must've just missed out on RTL by not all that long, it was only just
becoming scarce in component catalogues of the day.

DTL was better, it was faster too IIRC.


IIRC the crystal was 3MHz, I assume they'd run the MOS shift registers as
fast as they could get away with - and that would probably be what set the
upper limit.

One shift register recirculated the product of calculations past a row of
TTL 7475s which latched the "correct answer" every time it whizzed past.

I think the BCD to Nixie decoder/drivers were also TTL, the bulk of the
chips (over 200) were DTL.

In the late sixties or maybe very early seventies I build a frequency
counter
with 4790 decade counters, and 7475 latches,
cannot remember the number of the nixie driver chips, also TTL.
It had a 100 kHz crystal as reference, 5 digits, counted up to about 30
MHz,
as that was the maximum where the TTL would still work.


The Nixie drivers in the calculators might have been 8T series - but its a
long time to remember obscure details like that!

"Jan Panteltje" wrote in message
...
On a sunny day (Fri, 1 Feb 2013 11:13:45 -0800) it happened
(Dave Platt) wrote in :

In article ,
Jan Panteltje wrote:

Also how to tell you have a "digital" transistor in front of you?

WTF is a 'digital transistor'?????????????????

This is a fairly common term for a composite device... it's packaged
like an ordinary transistor (SMT or TO-92), but includes a
current-limiting resistor in the base lead (and often a base-to-
emitter pulldown).

It's used as a power-switching device, driven directly from a logic
signal (often a microcontroller pin).

Think of it as "just about the simplest sort of 'integrated circuit'
you can imagine". It's even simpler than the tiny little "simple glue
logic" chips you can buy these days (e.g. a NOT gate in a four-pin SMT
package, or a NAND in a 5-pin).

For a very short moment I did think 'unijunction transistor',
at least those are either on or off, but then I dismiossed that on
context.
I bought a bunch of 2n4246 UJTs last year from ebay.
Make nice oscillators.

I always preferred the programmable unijunction (a SS thyristor with the
gate on the anode instead of the cathode) - in fact you can turn the
standard relaxation oscillator upside down to suit a TO92 SS thyristor such
as 2N5061 MC100-4 etc - these SS SCRs are typically found in TV/monitor PSU
OVP shutdown latches.

Before Television Magazine went tits-up, I had a tester published with an
upside down relaxation oscillator to flash an LED (testing the SS SCR) and
also drive the IRLED in a high isolation opto-isolator that has no base pin
for the photo-transistor and can't be given the basic back-to-back diode
check.

On a sunny day (Fri, 1 Feb 2013 22:06:19 -0000) it happened "Ian Field"
wrote in :

I always preferred the programmable unijunction (a SS thyristor with the
gate on the anode instead of the cathode) - in fact you can turn the
standard relaxation oscillator upside down to suit a TO92 SS thyristor such
as 2N5061 MC100-4 etc - these SS SCRs are typically found in TV/monitor PSU
OVP shutdown latches.

Before Television Magazine went tits-up, I had a tester published with an
upside down relaxation oscillator to flash an LED (testing the SS SCR) and
also drive the IRLED in a high isolation opto-isolator that has no base pin
for the photo-transistor and can't be given the basic back-to-back diode
check.

Yes, I have seen those programmable ones, IIRC Philips had one in there
ultrasonic remote control.
I have used the 2n2646 as H and V oscillator in a vidicon camera I designed in 1968,
and later as trigger impulse generator to drive thyristors in big 3 phase power equipment,
via an impulse transformer.

Yes it is in a way a pity that many of those magazines no longer exist,
but internet makes it easier to publish for everybody, and easier to obtain info.
My website:
http://panteltje.com/index1.html
Dump place for pictures:
http://panteltje.com/pub/
Latest project (just showing of ;-))
http://panteltje.com/panteltje/xpsa/

On Fri, 1 Feb 2013 16:46:09 -0000, "Ian Field"
wrote:



"Jan Panteltje" wrote in message
...
On a sunny day (Fri, 1 Feb 2013 10:42:07 -0000) it happened "N_Cook"
wrote in :

Frank Miles wrote in message
...
On Thu, 31 Jan 2013 13:00:32 -0600, Frnak McKenney wrote:

Hm... is there a way of testing ( say ) a BJT's BVce "gently", that
is,
so that it doesn't _stay_ broken down?

Frank McKenney

Sure, a real BJT (perhaps excepting some RF exotica) can be pushed
beyond
BVce so long as current is kept low. You can see this quite nicely on a
curve tracer if you have access to one. I haven't heard of any problems
with devices "abused" in this way, not even MTBF.

BVeb is another matter. Breaking down EB junctions reduces beta,
increasing noise and may lead to shortened MTBF. Supposedly forward
biasing "anneals", but I don't know if it's completely reversible.
IIRC its a function of total-reverse-charge, so you should be able to go
into a very limited breakdown for a short time without "significant"
damage - perfectly sufficient for a tester.

-F


Also how to tell you have a "digital" transistor in front of you?

WTF is a 'digital transistor'?????????????????

Its a regular transistor with built in resistors - some are exactly
described that way rather than "digital", the most common arrangement is a
B-E bleed resistor + a base series current limiting resistor.

They are often used directly as an open collector inverter gate.

Also called "pre-biased transistors" or "resistor-equipped
transistors" (RETs).

Jan Panteltje wrote:

In the late sixties or maybe very early seventies I build a frequency counter
with 4790 decade counters, and 7475 latches,
cannot remember the number of the nixie driver chips, also TTL.


7441

On 2013-02-01, N_Cook wrote:

Also how to tell you have a "digital" transistor in front of you?

does B-E look like a diode or a diode plus some resistors.





--
š‚šƒ 100% natural

--- news://freenews.netfront.net/ - complaints: ---

On 2013-02-01, N_Cook wrote:
Jan Panteltje wrote in message


WTF is a 'digital transistor'?????????????????

Exactly, thats how they are referred to in UK listings, and without any " "s

have a look at some datasheets, they'e just odinary transistors with a
resistor network on base and emitter (or a single resistor on the base)

--
š‚šƒ 100% natural

On Fri, 01 Feb 2013 18:53:59 GMT, the renowned Jan Panteltje
wrote:


In the late sixties or maybe very early seventies I build a frequency counter
with 4790 decade counters, and 7475 latches,

7490.. one of the TTL chips with power pins not in the corners.

cannot remember the number of the nixie driver chips, also TTL.

7441 or 74141

It had a 100 kHz crystal as reference, 5 digits, counted up to about 30 MHz,
as that was the maximum where the TTL would still work.


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

On Fri, 1 Feb 2013 16:55:24 -0000, the renowned "Ian Field"
wrote:



"Jan Panteltje" wrote in message
...
On a sunny day (Fri, 01 Feb 2013 13:17:42 GMT) it happened Jan Panteltje
wrote in :


OK, but that is actually an integrated circuit.
Just mis-labeled 'transistor'.
:-)

PS,
some of us here will remember RTL logic.
That was pretty much like that, but more transistors to make gates, and
output R too.
Integrated circuits.


My first job was component level fault finding on Olympia desk calculators,
they contained about 4 boards of DTL - a 5th board at the back was
critically sensitive MOS shift registers. The boards were about the same
area as S100, but wider & not so high, the front board had about a dozen
nixie tubes.

I must've just missed out on RTL by not all that long, it was only just
becoming scarce in component catalogues of the day.

When I was a kid RTL became very available in surplus surface-mount
packages (called "flat pack"). Probably some big military change-over.
DTL didn't seem to last long.

Spacing was tight for attaching fly wires.. looks like it was
relatively coarse by today's standards- maybe 1.27mm pitch like
today's SOICs.


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

On a sunny day (Sat, 02 Feb 2013 05:25:57 -0500) it happened Spehro Pefhany
wrote in
:

On Fri, 1 Feb 2013 16:55:24 -0000, the renowned "Ian Field"
wrote:



"Jan Panteltje" wrote in message
...
On a sunny day (Fri, 01 Feb 2013 13:17:42 GMT) it happened Jan Panteltje
wrote in :


OK, but that is actually an integrated circuit.
Just mis-labeled 'transistor'.
:-)

PS,
some of us here will remember RTL logic.
That was pretty much like that, but more transistors to make gates, and
output R too.
Integrated circuits.


My first job was component level fault finding on Olympia desk calculators,
they contained about 4 boards of DTL - a 5th board at the back was
critically sensitive MOS shift registers. The boards were about the same
area as S100, but wider & not so high, the front board had about a dozen
nixie tubes.

I must've just missed out on RTL by not all that long, it was only just
becoming scarce in component catalogues of the day.

When I was a kid RTL became very available in surplus surface-mount
packages (called "flat pack"). Probably some big military change-over.
DTL didn't seem to last long.

You could get cheap DTLand TTL chips here sold as 'bipack'.
Those were for example 7474 D flip flops with one defective flip flop in the package,
or a 7400 with one or more gates defective.
Once bought some of those, tested them, and marked the defective pins with
red marker.
Great for hobby projects :-)
Not so good if you made a PCB I guess :-)



Spacing was tight for attaching fly wires.. looks like it was
relatively coarse by today's standards- maybe 1.27mm pitch like
today's SOICs.


mm I have wire wrapped several designs with TTL.

Jan Panteltje writes:

On a sunny day (Sat, 02 Feb 2013 05:25:57 -0500) it happened Spehro Pefhany
wrote in
:

On Fri, 1 Feb 2013 16:55:24 -0000, the renowned "Ian Field"
wrote:



"Jan Panteltje" wrote in message
...
On a sunny day (Fri, 01 Feb 2013 13:17:42 GMT) it happened Jan Panteltje
wrote in :


OK, but that is actually an integrated circuit.
Just mis-labeled 'transistor'.
:-)

PS,
some of us here will remember RTL logic.
That was pretty much like that, but more transistors to make gates, and
output R too.
Integrated circuits.


My first job was component level fault finding on Olympia desk calculators,
they contained about 4 boards of DTL - a 5th board at the back was
critically sensitive MOS shift registers. The boards were about the same
area as S100, but wider & not so high, the front board had about a dozen
nixie tubes.

I must've just missed out on RTL by not all that long, it was only just
becoming scarce in component catalogues of the day.

When I was a kid RTL became very available in surplus surface-mount
packages (called "flat pack"). Probably some big military change-over.
DTL didn't seem to last long.

You could get cheap DTLand TTL chips here sold as 'bipack'.
Those were for example 7474 D flip flops with one defective flip flop in the package,
or a 7400 with one or more gates defective.
Once bought some of those, tested them, and marked the defective pins with
red marker.
Great for hobby projects :-)
Not so good if you made a PCB I guess :-)

Hey I remember those, in UK you could get bags (literally) of 7400 and
4000 series stuff, all of them test rejects. Many of them unmarked or
with some house code I think. As a kid I built a succession of "IC
Testers" , fixtures with LEDs and push buttons on each pin. Never
actually *did* much with them, it was more fun testing them. The CMOS
gates were cool, you could make a the outputs go on and off by waving
your hand near them.


Spacing was tight for attaching fly wires.. looks like it was
relatively coarse by today's standards- maybe 1.27mm pitch like
today's SOICs.


mm I have wire wrapped several designs with TTL.



--

John Devereux

"Spehro Pefhany" wrote in message
...
On Fri, 01 Feb 2013 18:53:59 GMT, the renowned Jan Panteltje
wrote:


In the late sixties or maybe very early seventies I build a frequency
counter
with 4790 decade counters, and 7475 latches,

7490.. one of the TTL chips with power pins not in the corners.

cannot remember the number of the nixie driver chips, also TTL.

7441 or 74141


I remember that one - when I worked at the calculator repair firm, the chip
they used became temporarily unavailable.

After canibalising all the scrap boards we were pretty much scuppered - for
some reason it wasn't practical to patch the 74141 in.

"Jasen Betts" wrote in message
...
On 2013-02-01, N_Cook wrote:

Also how to tell you have a "digital" transistor in front of you?

does B-E look like a diode or a diode plus some resistors.

The (old) Peak Atlas reports 2 diodes if it can't find any gain.

John Devereux wrote:

Hey I remember those, in UK you could get bags (literally) of 7400 and
4000 series stuff, all of them test rejects. Many of them unmarked or
with some house code I think. As a kid I built a succession of "IC
Testers" , fixtures with LEDs and push buttons on each pin. Never
actually *did* much with them, it was more fun testing them. The CMOS
gates were cool, you could make a the outputs go on and off by waving
your hand near them.


Poly-Paks was THE place in the US to buy them. I bent the pins for
any bad section, and used lots of them to either build or repair
equipment that didn't need that section.

Poly-Paks also sold some parts by the pound. It was a good way for a
kid to get an assortment of resistors, caps sockets & such cheap enough
to learn electronics. Do you have any idea how many resistors were in a
five pound box?

On Sat, 02 Feb 2013 05:25:57 -0500, Spehro Pefhany
wrote:

On Fri, 1 Feb 2013 16:55:24 -0000, the renowned "Ian Field"
wrote:



"Jan Panteltje" wrote in message
...
On a sunny day (Fri, 01 Feb 2013 13:17:42 GMT) it happened Jan Panteltje
wrote in :


OK, but that is actually an integrated circuit.
Just mis-labeled 'transistor'.
:-)

PS,
some of us here will remember RTL logic.
That was pretty much like that, but more transistors to make gates, and
output R too.
Integrated circuits.


My first job was component level fault finding on Olympia desk calculators,
they contained about 4 boards of DTL - a 5th board at the back was
critically sensitive MOS shift registers. The boards were about the same
area as S100, but wider & not so high, the front board had about a dozen
nixie tubes.

I must've just missed out on RTL by not all that long, it was only just
becoming scarce in component catalogues of the day.

When I was a kid RTL became very available in surplus surface-mount
packages (called "flat pack"). Probably some big military change-over.
DTL didn't seem to last long.

Unless, of course, you count DTL redux (LSTTL). ;-)

Spacing was tight for attaching fly wires.. looks like it was
relatively coarse by today's standards- maybe 1.27mm pitch like
today's SOICs.


Best regards,
Spehro Pefhany