looking for a transistor

Guest
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.gleason@comcast.net
 
gleason@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?
Click to expand...

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/
 
gleason@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.gleason@comcast.net
where did you get the idea the 2222's can't handle that?
Click to expand...
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"
 
<gleason@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.gleason@comcast.net
Click to expand...
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
<jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote:

gleason@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.gleason@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.
Click to expand...
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_ka1lpa_@charter.net> wrote in message
news:tJyej.174$T05.48@newsfe06.lga...
gleason@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.gleason@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
Click to expand...
2n2222. Power here would be around a watt and a half...
--
Lee K. Gleason N5ZMR
Control-G Consultants
lee.gleason@comcast.net
 
"Lee K. Gleason" <lee.gleason@comcast.net> wrote in message
news:VLadnfYYge32XefanZ2dnUVZ_rKtnZ2d@comcast.com...
"Jamie" <jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote in
message
news:tJyej.174$T05.48@newsfe06.lga...
gleason@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.gleason@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.gleason@comcast.net
Click to expand...
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
 
Lee K. Gleason wrote:
"Jamie" <jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote in message
news:tJyej.174$T05.48@newsfe06.lga...

gleason@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.gleason@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.gleason@comcast.net
Click to expand...
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 120x1.8+32=250oF. Which TTL part are you using to drive
it? The 25mA base drive would suggest something called a *buffer*.
 
On Tue, 01 Jan 2008 14:35:12 -0800, John Larkin
<jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

On Tue, 01 Jan 2008 17:03:36 -0500, Jamie
jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote:

gleason@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.gleason@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
Click to expand...

Couldn't he just make a Darlington pair from two of the cheap 2n2222s?
 
On Tue, 01 Jan 2008 18:00:04 -0500, Fred Bloggs <nospam@nospam.com>
wrote:

Lee K. Gleason wrote:
"Jamie" <jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote in message
news:tJyej.174$T05.48@newsfe06.lga...

gleason@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.gleason@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.gleason@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 120x1.8+32=250oF. Which TTL part are you using to drive
it? The 25mA base drive would suggest something called a *buffer*.
Click to expand...
What about the 2222s in the can?
 
Fred Bloggs wrote:
Lee K. Gleason wrote:

"Jamie" <jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote in
message
news:tJyej.174$T05.48@newsfe06.lga...

gleason@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.gleason@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.gleason@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.
Click to expand...
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.
Click to expand...
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
Click to expand...
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.
Click to expand...
WTF...135oC

recall this is 120x1.8+32=250oF.
Click to expand...
....275oF

Which TTL part are you using to drive
it? The 25mA base drive would suggest something called a *buffer*.
Click to expand...
 
On Tue, 01 Jan 2008 18:00:04 -0500, Fred Bloggs <nospam@nospam.com>
wrote:

Lee K. Gleason wrote:
"Jamie" <jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote in message
news:tJyej.174$T05.48@newsfe06.lga...

gleason@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.gleason@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.gleason@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 120x1.8+32=250oF. Which TTL part are you using to drive
it? The 25mA base drive would suggest something called a *buffer*.
Click to expand...
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?
Click to expand...
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?
Click to expand...
And what's the Vce(sat) of a darlington ?

Graham
 
Jim Thompson wrote:
On Tue, 01 Jan 2008 18:00:04 -0500, Fred Bloggs <nospam@nospam.com
wrote:



Lee K. Gleason wrote:

"Jamie" <jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote in message
news:tJyej.174$T05.48@newsfe06.lga...


gleason@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.gleason@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.gleason@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 120x1.8+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
Click to expand...
Exactly- he needs to skip the SS stuff and go with a TIP31 grade medium
power part, well within its SOA...they're cheap.
 
On Tue, 01 Jan 2008 23:20:41 +0000, Eeyore
<rabbitsfriendsandrelations@hotmail.com> 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.

Graham
Click to expand...

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.

Otherwise, your CPU would be in plastic, idiot!

I guarantee the canned device has different numbers.

I wouldn't expect a retard like you to understand, however.
 
gleason@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?
Click to expand...
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
 
On Tue, 01 Jan 2008 21:10:10 -0500, John Popelish <jpopelish@rica.net>
wrote:

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:
Click to expand...

Zetex makes the best stuff on the planet.
 
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

<gleason@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.gleason@comcast.net
Click to expand...
 
gleason@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.gleason@comcast.net
Click to expand...
How about a ULN2001/2/3 darlington array. There will be 7 in a 16 dual
in line package.

Sal
 
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