I need to switch some GE #44 lamps from a TTL output. #44 lamps are 6.3 volts
at 250 ma, so I’ll need a transistor to do the real work. Unfortunately, it’s
just a hair too much power for one of the hundreds of surplus 2n2222′s I keep
around to do almost everything else here. Can someone suggest a small, cheap
available transistor that would be appropriate for this use?
—
Lee K. Gleason N5ZMR
Control-G Consultants
lee.glea…@comcast.net
27
Jan
looking for a transistor
posted by admin in Uncategorized and have Comments (24)
24 Responses to “looking for a transistor”
glea…@encompasserve.org wrote:
> I need to switch some GE #44 lamps from a TTL output. #44 lamps are 6.3 volts
> at 250 ma, so I’ll need a transistor to do the real work. Unfortunately, it’s
> just a hair too much power for one of the hundreds of surplus 2n2222′s I keep
> around to do almost everything else here. Can someone suggest a small, cheap
> available transistor that would be appropriate for this use?
Use a FET? The NDS351 comes to mind but only if it’s driven from 5V TTL
logic. Around $0.10 in large qties. If it’s 3.3V logic you’ll have to
keep looking for one that has guaranteed Rdson data down there and is
low enough in cost.
http://www.fairchildsemi.com/ds/ND/NDS351AN.pdf
–
Happy New Year, Joerg
http://www.analogconsultants.com/
glea…@encompasserve.org wrote:
> I need to switch some GE #44 lamps from a TTL output. #44 lamps are 6.3 volts
> at 250 ma, so I’ll need a transistor to do the real work. Unfortunately, it’s
> just a hair too much power for one of the hundreds of surplus 2n2222′s I keep
> around to do almost everything else here. Can someone suggest a small, cheap
> available transistor that would be appropriate for this use?
> —
> Lee K. Gleason N5ZMR
> Control-G Consultants
> lee.glea…@comcast.net
where did you get the idea the 2222′s can’t handle that?
You need to saturate them,. They can handle 500 ma’s so
said this PDF..
http://www.fairchildsemi.com/ds/PN/PN2222A.pdf
The trick is to saturate the bias so that very little
resistance effect is between the CE.
–
"I’d rather have a bottle in front of me than a frontal lobotomy"
http://webpages.charter.net/jamie_5"
<glea…@encompasserve.org> wrote in message
news:GcYrWMWoBeXi@eisner.encompasserve.org…
> I need to switch some GE #44 lamps from a TTL output. #44 lamps are 6.3
> volts
> at 250 ma, so I’ll need a transistor to do the real work. Unfortunately,
> it’s
> just a hair too much power for one of the hundreds of surplus 2n2222′s I
> keep
> around to do almost everything else here. Can someone suggest a small,
> cheap
> available transistor that would be appropriate for this use?
> —
> Lee K. Gleason N5ZMR
> Control-G Consultants
> lee.glea…@comcast.net
For switching DC voltage —
If the transistor is driven straight from a non-open collector IC — I
suggest using a high gain transistor such as MPSA13, MPSA14 or 2N6427 for
switching one lamp. If switching two lamps — MPSU45, CENU45, 2N6548 or
2N6549. None of these four are real popular, though. The CENU45′s are
still made – other three are tough to find.
If the transistor is driven from an open collector IC with a stiff pullup
resistor on the output then you can use something like a 2N6037 for
switching one or more lamps.
If the transistor is pre-driven by a pre-amplfication transistor (i.e.
2N2222) — then you can also use something like the 2N6037.
As an alternative, you can also use logic level driven MOSFET’s as well —
something like the IRL510 would drive lots of lamps.
If you’re switching AC voltage than use something like the Bally pinball
machines used — 2N5064 for one lamp or MCR106 for more than one lamp.
– Ed
On Tue, 01 Jan 2008 17:03:36 -0500, Jamie
- Hide quoted text — Show quoted text -
<jamie_ka1lpa_not_valid_after_ka1l…@charter.net> wrote:
>glea…@encompasserve.org wrote:
>> I need to switch some GE #44 lamps from a TTL output. #44 lamps are 6.3 volts
>> at 250 ma, so I’ll need a transistor to do the real work. Unfortunately, it’s
>> just a hair too much power for one of the hundreds of surplus 2n2222′s I keep
>> around to do almost everything else here. Can someone suggest a small, cheap
>> available transistor that would be appropriate for this use?
>> —
>> Lee K. Gleason N5ZMR
>> Control-G Consultants
>> lee.glea…@comcast.net
>where did you get the idea the 2222′s can’t handle that?
> You need to saturate them,. They can handle 500 ma’s so
>said this PDF..
>http://www.fairchildsemi.com/ds/PN/PN2222A.pdf
> The trick is to saturate the bias so that very little
>resistance effect is between the CE.
Yup, the 2222 is rated for a min beta of 40 at 500 mA. I’d just hook
the TTL output directly to the base!
(Ducks incoming flames.)
John
"Jamie" <jamie_ka1lpa_not_valid_after_ka1l…@charter.net> wrote in message
news:tJyej.174$T05.48@newsfe06.lga…
- Hide quoted text — Show quoted text -
> glea…@encompasserve.org wrote:
> > I need to switch some GE #44 lamps from a TTL output. #44 lamps are
6.3 volts
> > at 250 ma, so I’ll need a transistor to do the real work. Unfortunately,
it’s
> > just a hair too much power for one of the hundreds of surplus 2n2222′s
I keep
> > around to do almost everything else here. Can someone suggest a small,
cheap
> > available transistor that would be appropriate for this use?
> > —
> > Lee K. Gleason N5ZMR
> > Control-G Consultants
> > lee.glea…@comcast.net
> where did you get the idea the 2222′s can’t handle that?
> You need to saturate them,. They can handle 500 ma’s so
> said this PDF..
> http://www.fairchildsemi.com/ds/PN/PN2222A.pdf
> The trick is to saturate the bias so that very little
> resistance effect is between the CE.
I was concerned about the total power rating of 500 milliwatts for the
2n2222. Power here would be around a watt and a half…
—
Lee K. Gleason N5ZMR
Control-G Consultants
lee.glea…@comcast.net
"Lee K. Gleason" <lee.glea…@comcast.net> wrote in message
news:VLadnfYYge32XefanZ2dnUVZ_rKtnZ2d@comcast.com…
- Hide quoted text — Show quoted text -
> "Jamie" <jamie_ka1lpa_not_valid_after_ka1l…@charter.net> wrote in
> message
> news:tJyej.174$T05.48@newsfe06.lga…
>> glea…@encompasserve.org wrote:
>> > I need to switch some GE #44 lamps from a TTL output. #44 lamps are
> 6.3 volts
>> > at 250 ma, so I’ll need a transistor to do the real work.
>> > Unfortunately,
> it’s
>> > just a hair too much power for one of the hundreds of surplus 2n2222′s
> I keep
>> > around to do almost everything else here. Can someone suggest a small,
> cheap
>> > available transistor that would be appropriate for this use?
>> > —
>> > Lee K. Gleason N5ZMR
>> > Control-G Consultants
>> > lee.glea…@comcast.net
>> where did you get the idea the 2222′s can’t handle that?
>> You need to saturate them,. They can handle 500 ma’s so
>> said this PDF..
>> http://www.fairchildsemi.com/ds/PN/PN2222A.pdf
>> The trick is to saturate the bias so that very little
>> resistance effect is between the CE.
> I was concerned about the total power rating of 500 milliwatts for the
> 2n2222. Power here would be around a watt and a half…
> —
> Lee K. Gleason N5ZMR
> Control-G Consultants
> lee.glea…@comcast.net
That would need to be a pretty high saturation voltage in the transistor to
get 1.5W at 250mA.
The MPSA13 is rated at 625mW. With a saturation voltage of 1.5V and 400mA
(typical GE44 is actually about 400mA) — you’re dissipating 0.6W… maxing
out the MPSA13. Pinball people have been using MPSA13′s and GE44 bulbs for
years. The biggest problem happens when the bulb burns out. Unpredictable
things happen within the bulb when they burn out — sometimes the filliment
will break, move and ‘reweld’ itself to a different place in the
filliment — giving a brighter bulb…and short lifespan on the transistor.
You can also go with a type 47 bulb. Same voltage but about 250mA. Less
current so less power dissipated by transistor. Down side is the bulb is
considerably dimmer.
– Ed
- Hide quoted text — Show quoted text -
Lee K. Gleason wrote:
> "Jamie" <jamie_ka1lpa_not_valid_after_ka1l…@charter.net> wrote in message
> news:tJyej.174$T05.48@newsfe06.lga…
>>glea…@encompasserve.org wrote:
>>> I need to switch some GE #44 lamps from a TTL output. #44 lamps are
> 6.3 volts
>>>at 250 ma, so I’ll need a transistor to do the real work. Unfortunately,
> it’s
>>>just a hair too much power for one of the hundreds of surplus 2n2222′s
> I keep
>>>around to do almost everything else here. Can someone suggest a small,
> cheap
>>>available transistor that would be appropriate for this use?
>>>–
>>>Lee K. Gleason N5ZMR
>>>Control-G Consultants
>>>lee.glea…@comcast.net
>>where did you get the idea the 2222′s can’t handle that?
>> You need to saturate them,. They can handle 500 ma’s so
>>said this PDF..
>>http://www.fairchildsemi.com/ds/PN/PN2222A.pdf
>> The trick is to saturate the bias so that very little
>>resistance effect is between the CE.
> I was concerned about the total power rating of 500 milliwatts for the
> 2n2222. Power here would be around a watt and a half…
> —
> Lee K. Gleason N5ZMR
> Control-G Consultants
> lee.glea…@comcast.net
Look here at figure 2:
http://www.fairchildsemi.com/ds/PN/PN2222A.pdf
The little detail is that "beta=10" thingamjig…that means if you drive
the base with 25mA, the Vce at 250mA will be less than 0.2V. This makes
the Pd = 0.25A x 0.2V= 0.125W. Now look at figure 3, Vbe,sat, at 250mA
is about 0.9V. Use this to compute the voltage bucking your TTL drive.
Then the base dissipation is 0.025A x 0.9V=0.0225W. The grand total is
0.0225+0.125=0.1475W. Now go up to the top and look at R theta,j-a, of
200oC/W for the TO-92 plastic, that gets you 200oC/W x 0.1475W=29.5oC
junction rise above ambient. Now look at Tstg under max ratings, it says
150oC, this means you will be fine at ambients less than 150-30=120oC.
recall this is 120×1.8+32=250oF. Which TTL part are you using to drive
it? The 25mA base drive would suggest something called a *buffer*.
- Hide quoted text — Show quoted text -
Fred Bloggs wrote:
> Lee K. Gleason wrote:
>> "Jamie" <jamie_ka1lpa_not_valid_after_ka1l…@charter.net> wrote in
>> message
>> news:tJyej.174$T05.48@newsfe06.lga…
>>> glea…@encompasserve.org wrote:
>>>> I need to switch some GE #44 lamps from a TTL output. #44 lamps are
>> 6.3 volts
>>>> at 250 ma, so I’ll need a transistor to do the real work.
>>>> Unfortunately,
>> it’s
>>>> just a hair too much power for one of the hundreds of surplus 2n2222′s
>> I keep
>>>> around to do almost everything else here. Can someone suggest a small,
>> cheap
>>>> available transistor that would be appropriate for this use?
>>>> —
>>>> Lee K. Gleason N5ZMR
>>>> Control-G Consultants
>>>> lee.glea…@comcast.net
>>> where did you get the idea the 2222′s can’t handle that?
>>> You need to saturate them,. They can handle 500 ma’s so
>>> said this PDF..
>>> http://www.fairchildsemi.com/ds/PN/PN2222A.pdf
>>> The trick is to saturate the bias so that very little
>>> resistance effect is between the CE.
>> I was concerned about the total power rating of 500 milliwatts for the
>> 2n2222. Power here would be around a watt and a half…
>> —
>> Lee K. Gleason N5ZMR
>> Control-G Consultants
>> lee.glea…@comcast.net
> Look here at figure 2:
> http://www.fairchildsemi.com/ds/PN/PN2222A.pdf
> The little detail is that "beta=10" thingamjig…that means if you drive
> the base with 25mA, the Vce at 250mA will be less than 0.2V. This makes
> the Pd = 0.25A x 0.2V= 0.125W.
WTF…0.05W
>
>Now look at figure 3, Vbe,sat, at 250mA
> is about 0.9V. Use this to compute the voltage bucking your TTL drive.
> Then the base dissipation is 0.025A x 0.9V=0.0225W. The grand total is
> 0.0225+0.125=0.1475W.
WTF…0.0725W
> Now go up to the top and look at R theta,j-a, of
> 200oC/W for the TO-92 plastic, that gets you 200oC/W x 0.1475W=29.5oC
WTF…14.5oC
> junction rise above ambient. Now look at Tstg under max ratings, it says
> 150oC, this means you will be fine at ambients less than 150-30=120oC.
WTF…135oC
> recall this is 120×1.8+32=250oF.
…275oF
- Hide quoted text — Show quoted text -
> Which TTL part are you using to drive
> it? The 25mA base drive would suggest something called a *buffer*.
On Tue, 01 Jan 2008 18:00:04 -0500, Fred Bloggs <nos…@nospam.com>
wrote:
- Hide quoted text — Show quoted text -
>Lee K. Gleason wrote:
>> "Jamie" <jamie_ka1lpa_not_valid_after_ka1l…@charter.net> wrote in message
>> news:tJyej.174$T05.48@newsfe06.lga…
>>>glea…@encompasserve.org wrote:
>>>> I need to switch some GE #44 lamps from a TTL output. #44 lamps are
>> 6.3 volts
>>>>at 250 ma, so I’ll need a transistor to do the real work. Unfortunately,
>> it’s
>>>>just a hair too much power for one of the hundreds of surplus 2n2222′s
>> I keep
>>>>around to do almost everything else here. Can someone suggest a small,
>> cheap
>>>>available transistor that would be appropriate for this use?
>>>>–
>>>>Lee K. Gleason N5ZMR
>>>>Control-G Consultants
>>>>lee.glea…@comcast.net
>>>where did you get the idea the 2222′s can’t handle that?
>>> You need to saturate them,. They can handle 500 ma’s so
>>>said this PDF..
>>>http://www.fairchildsemi.com/ds/PN/PN2222A.pdf
>>> The trick is to saturate the bias so that very little
>>>resistance effect is between the CE.
>> I was concerned about the total power rating of 500 milliwatts for the
>> 2n2222. Power here would be around a watt and a half…
>> —
>> Lee K. Gleason N5ZMR
>> Control-G Consultants
>> lee.glea…@comcast.net
>Look here at figure 2:
>http://www.fairchildsemi.com/ds/PN/PN2222A.pdf
>The little detail is that "beta=10" thingamjig…that means if you drive
>the base with 25mA, the Vce at 250mA will be less than 0.2V. This makes
>the Pd = 0.25A x 0.2V= 0.125W. Now look at figure 3, Vbe,sat, at 250mA
>is about 0.9V. Use this to compute the voltage bucking your TTL drive.
>Then the base dissipation is 0.025A x 0.9V=0.0225W. The grand total is
>0.0225+0.125=0.1475W. Now go up to the top and look at R theta,j-a, of
>200oC/W for the TO-92 plastic, that gets you 200oC/W x 0.1475W=29.5oC
>junction rise above ambient. Now look at Tstg under max ratings, it says
>150oC, this means you will be fine at ambients less than 150-30=120oC.
>recall this is 120×1.8+32=250oF. Which TTL part are you using to drive
>it? The 25mA base drive would suggest something called a *buffer*.
The initial current surge (maybe 10x of normal) of the light bulb will
likely take out the transistor unless some sort of "soft-start" is
implemented.
…Jim Thompson
—
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC’s and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |
America: Land of the Free, Because of the Brave
ChairmanOfTheBored wrote:
> Fred Bloggs wrote:
> >Look here at figure 2:
> >http://www.fairchildsemi.com/ds/PN/PN2222A.pdf
> What about the 2222s in the can?
It’s the same die you bloody MORON.
Graham
ChairmanOfTheBored wrote:
> Couldn’t he just make a Darlington pair from two of the cheap 2n2222s?
And what’s the Vce(sat) of a darlington ?
Graham
- Hide quoted text — Show quoted text -
Jim Thompson wrote:
> On Tue, 01 Jan 2008 18:00:04 -0500, Fred Bloggs <nos…@nospam.com>
> wrote:
>>Lee K. Gleason wrote:
>>>"Jamie" <jamie_ka1lpa_not_valid_after_ka1l…@charter.net> wrote in message
>>>news:tJyej.174$T05.48@newsfe06.lga…
>>>>glea…@encompasserve.org wrote:
>>>>> I need to switch some GE #44 lamps from a TTL output. #44 lamps are
>>>6.3 volts
>>>>>at 250 ma, so I’ll need a transistor to do the real work. Unfortunately,
>>>it’s
>>>>>just a hair too much power for one of the hundreds of surplus 2n2222′s
>>>I keep
>>>>>around to do almost everything else here. Can someone suggest a small,
>>>cheap
>>>>>available transistor that would be appropriate for this use?
>>>>>–
>>>>>Lee K. Gleason N5ZMR
>>>>>Control-G Consultants
>>>>>lee.glea…@comcast.net
>>>>where did you get the idea the 2222′s can’t handle that?
>>>> You need to saturate them,. They can handle 500 ma’s so
>>>>said this PDF..
>>>>http://www.fairchildsemi.com/ds/PN/PN2222A.pdf
>>>> The trick is to saturate the bias so that very little
>>>>resistance effect is between the CE.
>>> I was concerned about the total power rating of 500 milliwatts for the
>>>2n2222. Power here would be around a watt and a half…
>>>–
>>>Lee K. Gleason N5ZMR
>>>Control-G Consultants
>>>lee.glea…@comcast.net
>>Look here at figure 2:
>>http://www.fairchildsemi.com/ds/PN/PN2222A.pdf
>>The little detail is that "beta=10" thingamjig…that means if you drive
>>the base with 25mA, the Vce at 250mA will be less than 0.2V. This makes
>>the Pd = 0.25A x 0.2V= 0.125W. Now look at figure 3, Vbe,sat, at 250mA
>>is about 0.9V. Use this to compute the voltage bucking your TTL drive.
>>Then the base dissipation is 0.025A x 0.9V=0.0225W. The grand total is
>>0.0225+0.125=0.1475W. Now go up to the top and look at R theta,j-a, of
>>200oC/W for the TO-92 plastic, that gets you 200oC/W x 0.1475W=29.5oC
>>junction rise above ambient. Now look at Tstg under max ratings, it says
>>150oC, this means you will be fine at ambients less than 150-30=120oC.
>>recall this is 120×1.8+32=250oF. Which TTL part are you using to drive
>>it? The 25mA base drive would suggest something called a *buffer*.
> The initial current surge (maybe 10x of normal) of the light bulb will
> likely take out the transistor unless some sort of "soft-start" is
> implemented.
> …Jim Thompson
Exactly- he needs to skip the SS stuff and go with a TIP31 grade medium
power part, well within its SOA…they’re cheap.
glea…@encompasserve.org wrote:
> I need to switch some GE #44 lamps from a TTL output. #44 lamps are 6.3 volts
> at 250 ma, so I’ll need a transistor to do the real work. Unfortunately, it’s
> just a hair too much power for one of the hundreds of surplus 2n2222′s I keep
> around to do almost everything else here. Can someone suggest a small, cheap
> available transistor that would be appropriate for this use?
I’m a sucker for the Zetex low saturation TO-92 transistors,
but they are not very cheap and made by no one else. But
drool over this data sheet:
http://www.zetex.com/3.0/pdf/ZTX1047A.pdf
But if I was going for dirt common and rugged, I would
probably go with a 3 amp rated power tab transistor mounted
standing straight up on the board.
Gain is more important than current rating, but look for
something with its peak gain in the 400 mA area or above,
for low base drive and saturation voltage. That puts you up
in the 3 to 6 amp rated sort of thing.
The TIP 31 has higher gain at 400 mA than the larger TIP41
has, so it is probably better, given the limited base drive.
http://www.fairchildsemi.com/ds/TI/TIP31.pdf
http://www.fairchildsemi.com/ds/TI/TIP41A.pdf
This one is pretty good at 400 mA, also.
http://www.fairchildsemi.com/ds/KS/KSC1173.pdf
But for my own stuff (not volume production design) I love
the Zetex. Having 3 or 4 times the current gain really
simplifies base drive and thermal problems.
–
Regards,
John Popelish
Bah. 2N2222 is the same thing as 2N4401, and I’ve got a 2N4401 in a
one-cell-powered-LED-inverter (apparently called a "Joule thief") running
as a blocking oscillator around 5MHz, with peak emitter current around
800mA. Saturation is under 0.3V. Okay, probably half of that is base
current, but it’s still more than low enough.
Use a PNP (2907/4403) to take advantage of the TTL’s current sinking
capacity.
Tim
–
Deep Fryer: A very philosophical monk.
Website @ http://webpages.charter.net/dawill/tmoranwms
<glea…@encompasserve.org> wrote in message
news:GcYrWMWoBeXi@eisner.encompasserve.org…
- Hide quoted text — Show quoted text -
> I need to switch some GE #44 lamps from a TTL output. #44 lamps are 6.3
volts
> at 250 ma, so I’ll need a transistor to do the real work. Unfortunately,
it’s
> just a hair too much power for one of the hundreds of surplus 2n2222′s I
keep
> around to do almost everything else here. Can someone suggest a small,
cheap
> available transistor that would be appropriate for this use?
> —
> Lee K. Gleason N5ZMR
> Control-G Consultants
> lee.glea…@comcast.net
glea…@encompasserve.org wrote:
> I need to switch some GE #44 lamps from a TTL output. #44 lamps are 6.3 volts
> at 250 ma, so I’ll need a transistor to do the real work. Unfortunately, it’s
> just a hair too much power for one of the hundreds of surplus 2n2222′s I keep
> around to do almost everything else here. Can someone suggest a small, cheap
> available transistor that would be appropriate for this use?
> —
> Lee K. Gleason N5ZMR
> Control-G Consultants
> lee.glea…@comcast.net
How about a ULN2001/2/3 darlington array. There will be 7 in a 16 dual
in line package.
Sal
- Hide quoted text — Show quoted text -
Jamie wrote:
> glea…@encompasserve.org wrote:
>> I need to switch some GE #44 lamps from a TTL output. #44 lamps are
>> 6.3 volts
>> at 250 ma, so I’ll need a transistor to do the real work.
>> Unfortunately, it’s
>> just a hair too much power for one of the hundreds of surplus
>> 2n2222′s I keep
>> around to do almost everything else here. Can someone suggest a small,
>> cheap
>> available transistor that would be appropriate for this use?
>> —
>> Lee K. Gleason N5ZMR
>> Control-G Consultants
>> lee.glea…@comcast.net
> where did you get the idea the 2222′s can’t handle that?
> You need to saturate them,. They can handle 500 ma’s so
> said this PDF..
> http://www.fairchildsemi.com/ds/PN/PN2222A.pdf
> The trick is to saturate the bias so that very little
> resistance effect is between the CE.
Those datashits are crap the way eveyone seems to misuse them.
The original 2N2222 was made for *small* signal work, and a practical
max current of about 100mA.
And even at that current, there is a large Vce drop.
Forcing a beta of five or less to get a "low" Vce is not a reasonable
way to use a transistor.
"Robert Baer" <robertb…@localnet.com> wrote in message
news:13nm4rtdmbl0l5d@corp.supernews.com…
> Forcing a beta of five or less to get a "low" Vce is not a reasonable
> way to use a transistor.
So every HOT ever made isn’t at all reasonable (hFE typ 2.5 to 5)?
:^)
Storage time sure goes to hell, though. Even fast HOTs are a couple
microseconds. ZTX651 is something like 800ns at beta = 10 (a good 10-20
times less than hFE at the same Ic).
At any rate, 2N2222 has a fat junction, and is specified for up to 500mA,
so there.
Tim
–
Deep Fryer: A very philosophical monk.
Website @ http://webpages.charter.net/dawill/tmoranwms
In article <13nm4rtdmbl0…@corp.supernews.com>,
Robert Baer <robertb…@localnet.com> wrote:
> Those datashits are crap the way eveyone seems to misuse them.
> The original 2N2222 was made for *small* signal work, and a practical
>max current of about 100mA.
> And even at that current, there is a large Vce drop.
> Forcing a beta of five or less to get a "low" Vce is not a reasonable
>way to use a transistor.
The OP might look into the 2N2222′s big brother, the 2N2219
(preferably the 2N2219A). According to a gent I know who did a lot of
solid-state design for GE some years back, the 2N2219 uses a die
similar to the 2N2222, but it’s spec’ed as a medium-current switch and
as it’s in a TO-39 can it has better heat dissipation capability than
the 2N2222. He described it as a "brutal" part – very useful for
driving lamps and relays.
One data sheet I have on it states an absolute-max of 800 mA collector
current, 800 mW with Tamb=25C (and absolute-max of 3 watts if you can
hold the case temperature to 25C), beta in the 150 mA collector-
current range is between 100 and 300, Vce saturates at around .3 volts
(all for the 2N2219A part).
Not modern, not elegant, but it has a long and honorable service
record. Dunno how easy they are to find these days… I bought a
whole bagful from a surplus dealer a couple of years ago.
–
Dave Platt <dpl…@radagast.org> 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!
ChairmanOfTheBored wrote:
> Eeyore wrote:
> >ChairmanOfTheBored wrote:
> >> Fred Bloggs wrote:
> >> >Look here at figure 2:
> >> >http://www.fairchildsemi.com/ds/PN/PN2222A.pdf
> >> What about the 2222s in the can?
> >It’s the same die you bloody MORON.
> Idiot! It is a well known FACT that a canned transistor can dissipate
> more heat than an epoxy package because it can sink it better and faster.
Not to free air it doesn’t.
2N2222 Pd = 500 mW
PN2222 Pd = 625 mW
> Otherwise, your CPU would be in plastic, idiot!
AMD CPUs have been manufactured in an epoxy based package for years (organic
PGA).
> I guarantee the canned device has different numbers.
Yes, it’s lower. Read the bloody datasheet !
> I wouldn’t expect a retard like you to understand, however.
I wouldn’t expect a retard like you to even begin to have a clue.
Graham
"GPE" <GPEnos…@cox.net> wrote in
news:IUyej.57604$Rw3.55123@newsfe06.phx:
> As an alternative, you can also use logic level driven MOSFET’s as
> well — something like the IRL510 would drive lots of lamps.
Indeed, and power MOSFET’s go very cheap in decent quantity on eBay at
times. So cheaply that it doesn’t make sense not to take advantage…
John Popelish <jpopel…@rica.net> wrote in
news:1dqdnR4N2YlibOfanZ2dnUVZ_vqpnZ2d@comcast.com:
> I’m a sucker for the Zetex low saturation TO-92 transistors,
> but they are not very cheap and made by no one else. But
> drool over this data sheet:
> http://www.zetex.com/3.0/pdf/ZTX1047A.pdf
Cool, someone mentions Zetex. They do seem to have a uniquely strong spec
for such small transistors. Even the tiny e-line thingers make some TO92
types look clumsy. Maybe the small size radiates heat better, less bulk to
seep through the way it must out of a TO92. For switching though, I’d still
prefer MOSFETs. Many will have VERY low RDS with a 5V gate input.
- Hide quoted text — Show quoted text -
Dave Platt wrote:
> In article <13nm4rtdmbl0…@corp.supernews.com>,
> Robert Baer <robertb…@localnet.com> wrote:
>> Those datashits are crap the way eveyone seems to misuse them.
>> The original 2N2222 was made for *small* signal work, and a practical
>>max current of about 100mA.
>> And even at that current, there is a large Vce drop.
>> Forcing a beta of five or less to get a "low" Vce is not a reasonable
>>way to use a transistor.
> The OP might look into the 2N2222′s big brother, the 2N2219
> (preferably the 2N2219A). According to a gent I know who did a lot of
> solid-state design for GE some years back, the 2N2219 uses a die
> similar to the 2N2222, but it’s spec’ed as a medium-current switch and
> as it’s in a TO-39 can it has better heat dissipation capability than
> the 2N2222. He described it as a "brutal" part – very useful for
> driving lamps and relays.
> One data sheet I have on it states an absolute-max of 800 mA collector
> current, 800 mW with Tamb=25C (and absolute-max of 3 watts if you can
> hold the case temperature to 25C), beta in the 150 mA collector-
> current range is between 100 and 300, Vce saturates at around .3 volts
> (all for the 2N2219A part).
> Not modern, not elegant, but it has a long and honorable service
> record. Dunno how easy they are to find these days… I bought a
> whole bagful from a surplus dealer a couple of years ago.
Makes no sense to use a pricey TO-39, there are now things like TIP30 in
TO-220, with specified SOA to handle his lamp turn-on surge, and the
bigger package means no heatsink required. Also, that one has Hfe nearly
100 typically at 250mA steady state, meaning he can drive it with any
TTL gate.
Lostgallifreyan wrote:
> Cool, someone mentions Zetex. They do seem to have a uniquely strong spec
> for such small transistors. Even the tiny e-line thingers make some TO92
> types look clumsy. Maybe the small size radiates heat better, less bulk to
> seep through the way it must out of a TO92.
(snip)
It has almost nothing to do with radiation, and everything
to do with conduction. The E-line has a copper lead frame,
with an over sized collector mounting flag that allows short
leads to large copper traces to carry away more heat.
http://www.zetex.com/3.0/appnotes/apps/an4.pdf
—
Regards,
John Popelish
On Wed, 02 Jan 2008 10:26:53 -0500, Fred Bloggs <nos…@nospam.com>
wrote:
- Hide quoted text — Show quoted text -
>Dave Platt wrote:
>> In article <13nm4rtdmbl0…@corp.supernews.com>,
>> Robert Baer <robertb…@localnet.com> wrote:
>>> Those datashits are crap the way eveyone seems to misuse them.
>>> The original 2N2222 was made for *small* signal work, and a practical
>>>max current of about 100mA.
>>> And even at that current, there is a large Vce drop.
>>> Forcing a beta of five or less to get a "low" Vce is not a reasonable
>>>way to use a transistor.
>> The OP might look into the 2N2222′s big brother, the 2N2219
>> (preferably the 2N2219A). According to a gent I know who did a lot of
>> solid-state design for GE some years back, the 2N2219 uses a die
>> similar to the 2N2222, but it’s spec’ed as a medium-current switch and
>> as it’s in a TO-39 can it has better heat dissipation capability than
>> the 2N2222. He described it as a "brutal" part – very useful for
>> driving lamps and relays.
>> One data sheet I have on it states an absolute-max of 800 mA collector
>> current, 800 mW with Tamb=25C (and absolute-max of 3 watts if you can
>> hold the case temperature to 25C), beta in the 150 mA collector-
>> current range is between 100 and 300, Vce saturates at around .3 volts
>> (all for the 2N2219A part).
>> Not modern, not elegant, but it has a long and honorable service
>> record. Dunno how easy they are to find these days… I bought a
>> whole bagful from a surplus dealer a couple of years ago.
>Makes no sense to use a pricey TO-39, there are now things like TIP30 in
>TO-220, with specified SOA to handle his lamp turn-on surge, and the
>bigger package means no heatsink required. Also, that one has Hfe nearly
>100 typically at 250mA steady state, meaning he can drive it with any
>TTL gate.
Or, if your nostalgia for the eighties is limited, use something like
this modern 37-cent part:
http://www.onsemi.com/pub/Collateral/NTR4501N-D.PDF
Best regards,
Spehro Pefhany
—
"it’s the network…" "The Journey is the reward"
sp…@interlog.com Info for manufacturers: http://www.trexon.com
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