Mimimum base current for 2N3055

dakupoto@gmail.com wrote:
> 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.

On Thu, 14 Feb 2013 23:25:39 -0800 (PST), dakupoto@gmail.com wrote:

>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.

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
Picosecond-resolution Digital Delay and Pulse generators
Custom laser drivers and controllers
Photonics and fiberoptic TTL data links
VME thermocouple, LVDT, synchro   acquisition and simulation

On Friday, February 15, 2013 3:39:05 PM UTC-5, John Larkin wrote:
> On Thu, 14 Feb 2013 23:25:39 -0800 (PST), dakupoto@gmail.com wrote:
> 
> 
> 
> >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.
> 
> 
> 
> 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. 


> 
> John Larkin         Highland Technology, Inc
> 
> 
> 
> jlarkin at highlandtechnology dot com
> 
> http://www.highlandtechnology.com
> 
> 
> 
> Precision electronic instrumentation
> 
> Picosecond-resolution Digital Delay and Pulse generators
> 
> Custom laser drivers and controllers
> 
> Photonics and fiberoptic TTL data links
> 
> VME thermocouple, LVDT, synchro   acquisition and simulation

On Fri, 15 Feb 2013 09:24:34 -0600, Tim Wescott
<tim@seemywebsite.please> wrote:

>On Thu, 14 Feb 2013 23:25:39 -0800, dakupoto wrote:
>
>> 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.  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.

dakupoto@gmail.com wrote:
> 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

"George Herold"
 dakup...@gmail.com
> 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

On Feb 15, 7:32=A0pm, "Phil Allison" <phi...@tpg.com.au> wrote:
> "George Herold"
> =A0dakup...@gmail.com
>
> > 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? =A0You can probably feed it 10nA and get ~1uA from
> the collector
>
> ** That is VERY unlikely - =A0the Hfe of power BJTs falls at low ( and hi=
gh)
> 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 =A0Motorola MJ4502s =
=A0- =A0I
> came across one that tested 450 at 1mA Ic.
>
> I thought of framing it....
>
> .... =A0Phil

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.

"George Herold"
 "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. 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....
>

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

On Fri, 15 Feb 2013 18:04:55 -0500, Jamie
<jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote:

>dakupoto@gmail.com wrote:
>> 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

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.

On Fri, 15 Feb 2013 11:20:44 -0800 (PST), whit3rd <whit3rd@gmail.com>
wrote:

>On Thursday, February 14, 2013 11:25:39 PM UTC-8, daku...@gmail.com wrote:
> 
>> 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).

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

RL