Mimimum base current for 2N3055

[[email protected]]

Could some electronics guru please help ?
What is the minimum base current for the
2N3055 ? The On Semi data sheet that I
downloaded is not very helpful. Thanks in
advance for your help.

 

[Phil Allison]

Could some electronics guru please help ?
What is the minimum base current for the
2N3055 ? The On Semi data sheet that I
downloaded is not very helpful.

** You Q makes no sense.

Some context is ESSENTIAL !!



..... Phil

 

[George Herold]

Could some electronics guru please help ?
What is the minimum base current for the
2N3055 ? The On Semi data sheet that I
downloaded is not very helpful. Thanks in
advance for your help.

Minimum base current? You can probably feed it 10nA and get ~1uA from
the collector... but that would be a pretty silly thing to do.

If you're looking at the same data sheet I down loaded then figure 2
shows typical current gain vs collecter current. (divide Ic by hfe
and you have an estimate of the base current you'll need.) Unless you
want to saturate the thing... then figure 3 is your friend.

As Phil and JF said, more context is needed if you want more specific
advice.

George H.

 

[Tim Williams]

Zero. Just leave the base disconnected.

Or if you mean direction, not just magnitude, then you can probably sink
five or ten amperes out of it ("IB2 = -5A" or whatever), during reverse
recovery of the B-E junction. It'll only last a couple microseconds
though.

Tim

 

[Spehro Pefhany]

Minimum base current? You can probably feed it 10nA and get ~1uA from
the collector... but that would be a pretty silly thing to do.

You could feed it a negative current too.. minimum current to damage
the E-B junction? Minimum current to burn off the bonding wire?

 

[John Devereux]

You could feed it a negative current too.. minimum current to damage
the E-B junction? Minimum current to burn off the bonding wire?

Yes I was torn between "zero" and some negative damage threshold.

I thought I saw something about 2N3055 being good for a low noise
amplifier, which sounds ridiculous but could be related...

[...]

 

[whit3rd]

What is the minimum base current for the
2N3055 ? The On Semi data sheet that I
downloaded is not very helpful.

It's not a switching device, so the current into the base
has a 'minimum' only in the sense that a hot device under
bias leaks from the collector. So, to reliably turn OFF the
transistor, you might need to sink 200 mA/beta
at 25 C, 60Vce (that's circa 2 mA).

The specs on beta (also known as h_fe) are, of course,
very loose; 20 to 70 at 4A, and there's temperature
and collector-current variations in the charts.

My source here is the RCA file #145, dated August 1966
(that's the most complete data sheet I know of for this part).

 

[Robert Baer]

Could some electronics guru please help ?
What is the minimum base current for the
2N3055 ? The On Semi data sheet that I
downloaded is not very helpful. Thanks in
advance for your help.

Zero.

 

[[email protected]]

If you're using the collector to switch some load on and off, at X

amps, you need to jam in maybe X/20 or even X/10 amps into the base.

Look at the data sheet for details. The more base current, the less

"on" resistance of the collector switch action.

Finally someone who can actually understand the question.

 

[[email protected]]

Zero. Just leave the base disconnected.

If this answer frustrates you, re-read your question and ask yourself
what other answer could be given.

I did that on a physics exam in college. The question didn't
eliminate the trivial answer. The prof thought I was being a smartass
and I thought he was throwing out one of his famous trick questions.
It did seem a little odd that zero being the answer to that question
made the next quarter of the exam result in zero answers, also (a bit
much for a trick question but it was correct). He was a bit miffed
but gave me credit on the exam. It was a correct answer.

 

[Jamie]

Could some electronics guru please help ?
What is the minimum base current for the
2N3055 ? The On Semi data sheet that I
downloaded is not very helpful. Thanks in
advance for your help.

I think you're talking about the Beta(Hfe) curve..
should be a chart in the spec showing at what point the
transfer is at the max.

That's an old part and many published data sheets.

Some one told me once that a 3055 was just a ball
park component, soured from various other high power
transistors that may have not met their mark. If that
being the case, it's possible you may find large noticeable
differences from lot to lot.


Jamie

 

[Phil Allison]

"George Herold"
[email protected]

Could some electronics guru please help ?
What is the minimum base current for the
2N3055 ? The On Semi data sheet that I
downloaded is not very helpful. Thanks in
advance for your help.

Minimum base current? You can probably feed it 10nA and get ~1uA from
the collector

** That is VERY unlikely - the Hfe of power BJTs falls at low ( and high)
currents so much so that most data sheets do not spec it below about 50mA
Ic.

Long time ago, I was checking the Hfe of a batch of Motorola MJ4502s - I
came across one that tested 450 at 1mA Ic.

I thought of framing it....


..... Phil

 

[George Herold]

"George Herold"
 [email protected]


Minimum base current?  You can probably feed it 10nA and get ~1uA from
the collector

** That is VERY unlikely -  the Hfe of power BJTs falls at low ( and high)
currents so much so that most data sheets do not spec it below about 50mA
Ic.

Long time ago, I was checking the Hfe of a batch of  Motorola MJ4502s  -  I
came across one that tested 450 at 1mA Ic.

I thought of framing it....

....  Phil

Well OK, I've been using these TIP31/32 's in to220 pacs as temp
sensors,
diode conected transitors. At 10nA of collector current the ideality
is starting to fall off, 100nA looks OK. I figured a higher power BJT
might be 'good' to 1uA.

Have you measured a 3055 at 1uA?
(I did say probably..)

George H.

 

[Phil Allison]

"George Herold"
"Phil Allison"

Minimum base current? You can probably feed it 10nA and get ~1uA from
the collector

** That is VERY unlikely - the Hfe of power BJTs falls at low ( and high)
currents so much so that most data sheets do not spec it below about 50mA
Ic.

Long time ago, I was checking the Hfe of a batch of Motorola MJ4502s - I
came across one that tested 450 at 1mA Ic.

I thought of framing it....

Well OK, I've been using these TIP31/32 's in to220 pacs as temp
sensors, diode conected transitors. At 10nA of collector current the
ideality is starting to fall off, 100nA looks OK. I figured a higher
power BJT might be 'good' to 1uA.


** So you just fucking guessed.

How typical for this NG.

Have you measured a 3055 at 1uA?

** Hundreds of them.


FYI:

I just tested a vintage 1983 MJ802.

With 1uA base current, Ic = 4uA

With 100uA base current , Ic = 1.8 mA

With 4.5mA base current, Ic = 0.6 A



..... Phil

 

[[email protected]]

I think you're talking about the Beta(Hfe) curve..
should be a chart in the spec showing at what point the
transfer is at the max.

That's an old part and many published data sheets.

Some one told me once that a 3055 was just a ball
park component, soured from various other high power
transistors that may have not met their mark. If that
being the case, it's possible you may find large noticeable
differences from lot to lot.


Jamie

According to urban legends, some manufacturers even branded failed VHF
transmitter transistors as 2N3055 and caused huge stability problems
in existing circuits

So if the original specification called for fT > 0.8 MHz, so it would
be OK to sell a transistor with fT > 500 MHz as long as the other
requirements were met.

 

[legg]

It's not a switching device, so the current into the base
has a 'minimum' only in the sense that a hot device under
bias leaks from the collector. So, to reliably turn OFF the
transistor, you might need to sink 200 mA/beta
at 25 C, 60Vce (that's circa 2 mA).

That's Icbo to all you sports fans out there.

RL

 

[[email protected]]

If you're using the collector to switch some load on and off, at X

amps, you need to jam in maybe X/20 or even X/10 amps into the base.

Look at the data sheet for details. The more base current, the less

"on" resistance of the collector switch action.



Mosfets are easier to drive. Just apply some voltage (like 10v maybe)

to the gate to turn them on, zero to turn them off. The gate current

is minute.





--



John Larkin Highland Technology, Inc



jlarkin at highlandtechnology dot com

http://www.highlandtechnology.com



Precision electronic instrumentation

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Thanks. As one of the other posters have noted,
the specifications are pretty loose, in that
most (like the one from On Semi) state that
hfe varies between 20 - 70, and at hfe of 70,
the collector current is 4.0 A, which is not
very helpful. What you have said, is however
a lot more concrete.

 

[[email protected]]

Finally someone who can actually understand the question.

I fully agree.

 

[Phil Allison]

I fully agree.

** You are fully a fuckwit and a troll.

Learn to write English properly or else **** OFF !!!!



..... Phil

 

[Phil Allison]

As one of the other posters have noted,
the specifications are pretty loose, in that
most (like the one from On Semi) state that
hfe varies between 20 - 70, and at hfe of 70,
the collector current is 4.0 A, which is not
very helpful.

** OK so you CANNOT read English either.

You are quite wrong and you have no comprehension of the topic.

**** off.


...... Phil