Maker Pro
Maker Pro

Cooking transistors: any recommendations?

P

Paul Burridge

Jan 1, 1970
0
With "cooking" as an adjective rather than a verb!
I'm just looking for recommendations as to a general purpose 'cooking'
transistor that's a sufficiently good compromise to be able to
reasonably handle both switching and linear amplification with low-ish
noise. The kind of discrete device you can buy dirt cheap by the
bucket-load. Power handling and transition frequency not critical;
just a bonus.
Anyone got any favourites they'd care to name?

p.
 
T

Tim Shoppa

Jan 1, 1970
0
Paul said:
With "cooking" as an adjective rather than a verb!

Around here the preferred term seems to be "jellybean". You buy
them in quantity, toss them off wherever you need them.
I'm just looking for recommendations as to a general purpose 'cooking'
transistor that's a sufficiently good compromise to be able to
reasonably handle both switching and linear amplification with low-ish
noise. The kind of discrete device you can buy dirt cheap by the
bucket-load. Power handling and transition frequency not critical;
just a bonus.
Anyone got any favourites they'd care to name?

2N4401 for medium-voltage low-current NPN bipolar applications. 2N4403
is PNP counterpart. The plastic 2N2222/2N3904/2N3906 are similar but
not quite as good for most purposes.

MPSA42 for voltages up to low hundred V in NPN. MPSA92 for PNP.

ULN2003/2803 when you need 7 or 8 NPN common-emitter switches in a
single package.

Above currents of a few hundred mA or powers above a fractional watt,
things aren't so jellybeanish. TIP30/TIP31/2N3055 are common choices
and readily available but really are far from the cream of the crop
compared to better and likely cheaper choices for individual
applications.
Non-bipolar transistors are often superior choices, the 2N7000 for
example. Even though everyone will tell you it's a switch,
I've seen it used in some surprising linear applications!

Tim.
 
J

John Popelish

Jan 1, 1970
0
Paul said:
With "cooking" as an adjective rather than a verb!
I'm just looking for recommendations as to a general purpose 'cooking'
transistor that's a sufficiently good compromise to be able to
reasonably handle both switching and linear amplification with low-ish
noise. The kind of discrete device you can buy dirt cheap by the
bucket-load. Power handling and transition frequency not critical;
just a bonus.
Anyone got any favourites they'd care to name?

Low level, low noise, high gain less than 50 mA collector current):
NPN 2N5089
http://www.onsemi.com/pub/Collateral/2N5088-D.PDF
PNP 2N5087
http://www.onsemi.com/pub/Collateral/2N5087-D.PDF

General purpose, less than 300mA collector current:
NPN 2N4401
http://www.onsemi.com/pub/Collateral/2N4401-D.PDF
PNP 2N4403
http://www.onsemi.com/pub/Collateral/2N4403-D.PDF

You will never run out of things you can build with these 4.
 
A somewhat indirect answer to your question would be that when
designing its good practice to specify more than one device that can be
used. This is usually easy with ubiquitous little trannies, rather less
so with power devices.

Designing for several possibles makes sourcing much easier, and reduces
stock range, which all helps reduce costs. Its especially useful when
designing for a company in another country.

It isnt always appropriate of course.


NT
 
A

Adrian Tuddenham

Jan 1, 1970
0
With "cooking" as an adjective rather than a verb!
I'm just looking for recommendations as to a general purpose 'cooking'
transistor that's a sufficiently good compromise to be able to
reasonably handle both switching and linear amplification with low-ish
noise. The kind of discrete device you can buy dirt cheap by the
bucket-load. Power handling and transition frequency not critical;
just a bonus.
Anyone got any favourites they'd care to name?

Among the ZTX000 series are some pretty good workhorses suitable for
around 1 to 2 amps and up to over 100v - but they aren't the rock-bottom
cheapest.
 
J

John Larkin

Jan 1, 1970
0
With "cooking" as an adjective rather than a verb!
I'm just looking for recommendations as to a general purpose 'cooking'
transistor that's a sufficiently good compromise to be able to
reasonably handle both switching and linear amplification with low-ish
noise. The kind of discrete device you can buy dirt cheap by the
bucket-load. Power handling and transition frequency not critical;
just a bonus.
Anyone got any favourites they'd care to name?

p.

I like BCX70/71. Betas are huge.

And 2N7002 whan a fet is appropriate, which is most of the time.

John
 
T

Tim Wescott

Jan 1, 1970
0
A somewhat indirect answer to your question would be that when
designing its good practice to specify more than one device that can be
used. This is usually easy with ubiquitous little trannies, rather less
so with power devices.

Designing for several possibles makes sourcing much easier, and reduces
stock range, which all helps reduce costs. Its especially useful when
designing for a company in another country.

It isnt always appropriate of course.


NT
I've had a couple of bottles of TO-92 case transistors for 20 years now;
I'm slowly working through them. They're from a big box of stuff
donated by Tektronix to the Portland State IEEE student chapter. We
just loaded up a pound (or maybe 5) of stuff per box and sold them for a
couple of bucks per box.

They're all house-marked, but whenever I need a jellybean small signal
transistor I just shake one out and use it. Hasn't gone wrong yet.
 
T

Tim Williams

Jan 1, 1970
0
Paul Burridge said:
With "cooking" as an adjective rather than a verb!

Well I don't care! I personally like them smoked over an open fire...

Tim
 
B

Barry Lennox

Jan 1, 1970
0
With "cooking" as an adjective rather than a verb!
I'm just looking for recommendations as to a general purpose 'cooking'
transistor that's a sufficiently good compromise to be able to
reasonably handle both switching and linear amplification with low-ish
noise. The kind of discrete device you can buy dirt cheap by the
bucket-load. Power handling and transition frequency not critical;
just a bonus.
Anyone got any favourites they'd care to name?


"Cooking" should be anything you can get cheap or surplus: Personally
I have scored, free, or almost for free, large qtys of:

ZTX xxx (Several p/ns)
2N2369A
2N3055 both metal and plastic
and several others whose specs are almost irrelevant, I just got
hundreds for free.

They all work fine,

Barry Lennox
 
J

John Larkin

Jan 1, 1970
0
Tim Wescott wrote...

That's the term we tend to use, instead of cooking.


Maybe back East you do. Out West we call them gumdrops.

John
 
T

Tam/WB2TT

Jan 1, 1970
0
Paul Burridge said:
With "cooking" as an adjective > Anyone got any favourites they'd care to
name?

p.
--


2N2369 for NPN
2N5771 for PNP

Tam
 
J

John S. Dyson

Jan 1, 1970
0
2N2369 for NPN
2N5771 for PNP
Aren't 2n2369s gold doped? (It has been a long time since I played
with those.) IF they are gold doped, they might not be optimal
for small signal applications (they might be a little more noisy.)
Perhaps it was the 2n706 that were gold doped? I seem to remember that
the 2n706 tended to be noisy as HF/VHF oscillators. AFAIR, the gold
doping helped to mitigate some of the storage effects of saturation.

2n2369s are moderately fast (given transistors of that era), and I
seem to remember that the batch that I had many years ago had the cool
negative resistance effect (leave base open, relaxation oscillator
with neg resistance between collector/emitter. I seem to remember that
it required 20-30V of bias. The transistor would no longer work very
well as a regular transistor after abusing it as a negative resistance
oscillator, but YMMV.) These memories come from the 1970-1975 timeframe,
so might be a little distorted.

Nowadays, for non-switching applications, perhaps an MPSH10 might
be a slightly better choice for the NPN.

John
 
R

Rich Grise

Jan 1, 1970
0
I've had a couple of bottles of TO-92 case transistors for 20 years now;
I'm slowly working through them. They're from a big box of stuff
donated by Tektronix to the Portland State IEEE student chapter. We
just loaded up a pound (or maybe 5) of stuff per box and sold them for a
couple of bucks per box.

They're all house-marked, but whenever I need a jellybean small signal
transistor I just shake one out and use it. Hasn't gone wrong yet.

Is a "cooking" transistor a transistor that you cook with? ;-)

But speaking of grab-bags, I once had a job as a Radio Shack floordroid.
I saw them make up a grab-bag once, and it was composed of trash from
behind the counter (like, returns, or stuff that they didn't buy but
nobody had got around to re-shelving) and, yes, literally, stuff we found
on the floor.

Cheers!
Rich
 
Top