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Imagine an NPN transistor. Ground the emitter and connect the
collector to some nice positive voltage.
Now pull the base negative, through a current-limiting resistor. What
happens?
On 2023-09-06, John Larkin <jlarkin@highlandSNIPMEtechnology.com> wrote:
Imagine an NPN transistor. Ground the emitter and connect the
collector to some nice positive voltage.
Now pull the base negative, through a current-limiting resistor. What
happens?
Nothing until you exceed the emitter base reverse breakdown (or
collector base breakdown) voltage,
Bitter-base is usually about 5V
Behaves kind of like a zener diode and damages the transistor.
On Wed, 6 Sep 2023 00:58:11 -0000 (UTC), Jasen Betts
usenet@revmaps.no-ip.org> wrote:
On 2023-09-06, John Larkin <jlarkin@highlandSNIPMEtechnology.com> wrote:
Imagine an NPN transistor. Ground the emitter and connect the
collector to some nice positive voltage.
Now pull the base negative, through a current-limiting resistor. What
happens?
Nothing until you exceed the emitter base reverse breakdown (or
collector base breakdown) voltage,
Not literally nothing, but not much interesting. It gets more
interesting when the base zeners.
Bitter-base is usually about 5V
Behaves kind of like a zener diode and damages the transistor.
The base current is limited. But what happens?
John Larkin <jlarkin@highlandSNIPMEtechnology.com> wrote:
On Wed, 6 Sep 2023 00:58:11 -0000 (UTC), Jasen Betts
usenet@revmaps.no-ip.org> wrote:
On 2023-09-06, John Larkin <jlarkin@highlandSNIPMEtechnology.com> wrote:
Imagine an NPN transistor. Ground the emitter and connect the
collector to some nice positive voltage.
Now pull the base negative, through a current-limiting resistor. What
happens?
Nothing until you exceed the emitter base reverse breakdown (or
collector base breakdown) voltage,
Not literally nothing, but not much interesting. It gets more
interesting when the base zeners.
Bitter-base is usually about 5V
Behaves kind of like a zener diode and damages the transistor.
The base current is limited. But what happens?
Havent tried it, at least not on purpose, but Id guess that when the
avalanche starts, most of the electrons will get sucked up by the
collector.
Since its the electrons and not the holes that do the avalanching in
silicon, that might partially suppress the avalanche. If that were true,
putting a positive voltage on the collector would make the base voltage
slightly more negative.
Cheers
Phil Hobbs
Imagine an NPN transistor. Ground the emitter and connect the
collector to some nice positive voltage.
Now pull the base negative, through a current-limiting resistor. What
happens?
On Tuesday, September 5, 2023 at 5:05:16?PM UTC-7, John Larkin wrote:
Imagine an NPN transistor. Ground the emitter and connect the
collector to some nice positive voltage.
Now pull the base negative, through a current-limiting resistor. What
happens?
The collector becomes a better OFF switch; the collector breakdown
Vceo applies when the base is open, but higher Vcbo applies
when base is held negative.
I suppose I should try it.
Imagine an NPN transistor. Ground the emitter and connect the
collector to some nice positive voltage.
Now pull the base negative, through a current-limiting resistor. What
happens?
On 06/09/2023 01:04, John Larkin wrote:
Imagine an NPN transistor. Ground the emitter and connect the
collector to some nice positive voltage.
Now pull the base negative, through a current-limiting resistor. What
happens?
If the collector is already positive
and pullup resistor is not
extremely high then I think not much detectable will happen even once
the Veb junction breaks down.
On Wed, 6 Sep 2023 19:19:20 +0100, piglet <erichp...@hotmail.com
wrote:
On 06/09/2023 01:04, John Larkin wrote:
Imagine an NPN transistor. Ground the emitter and connect the
collector to some nice positive voltage.
Now pull the base negative, through a current-limiting resistor. What
happens?
If the collector is already positive
That was a stated condition
and pullup resistor is not
extremely high then I think not much detectable will happen even once
the Veb junction breaks down.
\"Detectable\" can include amps or picoamps of currents.
Curious that nobody seems to address this case.
On Wednesday, September 6, 2023 at 2:59:10?PM UTC-5, John Larkin wrote:
On Wed, 6 Sep 2023 19:19:20 +0100, piglet <erichp...@hotmail.com
wrote:
On 06/09/2023 01:04, John Larkin wrote:
Imagine an NPN transistor. Ground the emitter and connect the
collector to some nice positive voltage.
Now pull the base negative, through a current-limiting resistor. What
happens?
If the collector is already positive
That was a stated condition
and pullup resistor is not
extremely high then I think not much detectable will happen even once
the Veb junction breaks down.
\"Detectable\" can include amps or picoamps of currents.
Curious that nobody seems to address this case.
How could the information be used? It seems to have not been needed in the past, yes?
On Wed, 6 Sep 2023 14:34:12 -0700 (PDT), John Smiht
utube.jocjo@xoxy.net> wrote:
On Wednesday, September 6, 2023 at 2:59:10?PM UTC-5, John Larkin wrote:
On Wed, 6 Sep 2023 19:19:20 +0100, piglet <erichp...@hotmail.com
wrote:
On 06/09/2023 01:04, John Larkin wrote:
Imagine an NPN transistor. Ground the emitter and connect the
collector to some nice positive voltage.
Now pull the base negative, through a current-limiting resistor. What
happens?
If the collector is already positive
That was a stated condition
and pullup resistor is not
extremely high then I think not much detectable will happen even once
the Veb junction breaks down.
\"Detectable\" can include amps or picoamps of currents.
Curious that nobody seems to address this case.
How could the information be used? It seems to have not been needed in the past, yes?
I\'d expect that understanding transistors is a generally good thing to
do. Looking at schematics on the web, it seems like few people do.
If it behaves as I suspect it may, I might have a use for it.
On 9/6/23 22:34, John Larkin wrote:
On Wed, 6 Sep 2023 14:34:12 -0700 (PDT), John Smiht
utube.jocjo@xoxy.net> wrote:
On Wednesday, September 6, 2023 at 2:59:10?PM UTC-5, John Larkin wrote:
On Wed, 6 Sep 2023 19:19:20 +0100, piglet <erichp...@hotmail.com
wrote:
On 06/09/2023 01:04, John Larkin wrote:
Imagine an NPN transistor. Ground the emitter and connect the
collector to some nice positive voltage.
Now pull the base negative, through a current-limiting resistor. What
happens?
If the collector is already positive
That was a stated condition
and pullup resistor is not
extremely high then I think not much detectable will happen even once
the Veb junction breaks down.
\"Detectable\" can include amps or picoamps of currents.
Curious that nobody seems to address this case.
How could the information be used? It seems to have not been needed in the past, yes?
I\'d expect that understanding transistors is a generally good thing to
do. Looking at schematics on the web, it seems like few people do.
If it behaves as I suspect it may, I might have a use for it.
Back in the 60\'s/70\'s there were some germanium transistors
marketed for avalanche pulse generator work. May have been
Mullard / Philips, but don\'t remember any circuit details.
Years ago, found myself fixing more than a few high power
audio amps and built a simple breakdown tester with a variac,
stepdown transformer, limiting resistor and full wave rectifer.
Got some interesting effects at breakdown, very high frequency
oscillation on the scope. 2n3055 class power devices, normally
quite low frequency use. Interesting effect, perhaps similar
to other weird stuff of the time, like impatt diodes...
Chris
On 9/6/23 22:34, John Larkin wrote:
On Wed, 6 Sep 2023 14:34:12 -0700 (PDT), John Smiht
utube.jocjo@xoxy.net> wrote:
On Wednesday, September 6, 2023 at 2:59:10?PM UTC-5, John Larkin wrote:
On Wed, 6 Sep 2023 19:19:20 +0100, piglet <erichp...@hotmail.com
wrote:
On 06/09/2023 01:04, John Larkin wrote:
Imagine an NPN transistor. Ground the emitter and connect the
collector to some nice positive voltage.
Now pull the base negative, through a current-limiting resistor. What
happens?
If the collector is already positive
That was a stated condition
and pullup resistor is not
extremely high then I think not much detectable will happen even once
the Veb junction breaks down.
\"Detectable\" can include amps or picoamps of currents.
Curious that nobody seems to address this case.
How could the information be used? It seems to have not been needed in the past, yes?
I\'d expect that understanding transistors is a generally good thing to
do. Looking at schematics on the web, it seems like few people do.
If it behaves as I suspect it may, I might have a use for it.
Back in the 60\'s/70\'s there were some germanium transistors
marketed for avalanche pulse generator work. May have been
Mullard / Philips, but don\'t remember any circuit details.
Years ago, found myself fixing more than a few high power
audio amps and built a simple breakdown tester with a variac,
stepdown transformer, limiting resistor and full wave rectifer.
Got some interesting effects at breakdown, very high frequency
oscillation on the scope. 2n3055 class power devices, normally
quite low frequency use. Interesting effect, perhaps similar
to other weird stuff of the time, like impatt diodes...
On Wed, 6 Sep 2023 22:56:12 +0000, chrisq <devzero@nospam.com> wrote:
On 9/6/23 22:34, John Larkin wrote:
On Wed, 6 Sep 2023 14:34:12 -0700 (PDT), John Smiht
utube.jocjo@xoxy.net> wrote:
On Wednesday, September 6, 2023 at 2:59:10?PM UTC-5, John Larkin wrote:
On Wed, 6 Sep 2023 19:19:20 +0100, piglet <erichp...@hotmail.com
wrote:
On 06/09/2023 01:04, John Larkin wrote:
Imagine an NPN transistor. Ground the emitter and connect the
collector to some nice positive voltage.
Now pull the base negative, through a current-limiting resistor. What
happens?
If the collector is already positive
That was a stated condition
and pullup resistor is not
extremely high then I think not much detectable will happen even once
the Veb junction breaks down.
\"Detectable\" can include amps or picoamps of currents.
Curious that nobody seems to address this case.
How could the information be used? It seems to have not been needed in the past, yes?
I\'d expect that understanding transistors is a generally good thing to
do. Looking at schematics on the web, it seems like few people do.
If it behaves as I suspect it may, I might have a use for it.
Back in the 60\'s/70\'s there were some germanium transistors
marketed for avalanche pulse generator work. May have been
Mullard / Philips, but don\'t remember any circuit details.
Early Tek and HP sampling scopes used an avalanche transistor to drive
the sampler. I think maybe Lumatron did that first.
Years ago, found myself fixing more than a few high power
audio amps and built a simple breakdown tester with a variac,
stepdown transformer, limiting resistor and full wave rectifer.
Got some interesting effects at breakdown, very high frequency
oscillation on the scope. 2n3055 class power devices, normally
quite low frequency use. Interesting effect, perhaps similar
to other weird stuff of the time, like impatt diodes...
Chris
Transistors do all sorts of fun stuff that\'s not on the label.
Zetex makes SOT23 silicon transistors that are designed to avalanche.
As in <1 ns, 300 volts, 60 amps.
Some other tricks:
unclamped inductor flyback avalanche
zero volt saturation
step-recovery effects
stored charge effects
inverse beta
temp-compensated b-e zenering
On a sunny day (Wed, 6 Sep 2023 22:56:12 +0000) it happened chrisq <dev....@nospam.com> wrote in <udb02d$2m6li$1...@dont-email.me>:
On 9/6/23 22:34, John Larkin wrote:
On Wed, 6 Sep 2023 14:34:12 -0700 (PDT), John Smiht <utube...@xoxy.net> wrote:
On Wednesday, September 6, 2023 at 2:59:10?PM UTC-5, John Larkin wrote:
On Wed, 6 Sep 2023 19:19:20 +0100, piglet <erichp...@hotmail.com> wrote:
On 06/09/2023 01:04, John Larkin wrote:
Yes, and not all 2N3055 were the same, different manufactures.. diffferent ft
Build quite a few audio amps with those.
https://en.m.wikipedia.org/wiki/2N3055
Same likely goes for John Larkin\'s experiment,
And manufacturers can change process any time, not something recommended to use out of spec.
On Wed, 6 Sep 2023 22:56:12 +0000, chrisq <dev...@nospam.com> wrote:
On 9/6/23 22:34, John Larkin wrote:
On Wed, 6 Sep 2023 14:34:12 -0700 (PDT), John Smiht
utube...@xoxy.net> wrote:
On Wednesday, September 6, 2023 at 2:59:10?PM UTC-5, John Larkin wrote:
On Wed, 6 Sep 2023 19:19:20 +0100, piglet <erichp...@hotmail.com
wrote:
On 06/09/2023 01:04, John Larkin wrote:
Imagine an NPN transistor. Ground the emitter and connect the
collector to some nice positive voltage.
Now pull the base negative, through a current-limiting resistor. What
happens?
If the collector is already positive
That was a stated condition
and pullup resistor is not
extremely high then I think not much detectable will happen even once
the Veb junction breaks down.
\"Detectable\" can include amps or picoamps of currents.
Curious that nobody seems to address this case.
How could the information be used? It seems to have not been needed in the past, yes?
I\'d expect that understanding transistors is a generally good thing to
do. Looking at schematics on the web, it seems like few people do.
If it behaves as I suspect it may, I might have a use for it.
Back in the 60\'s/70\'s there were some germanium transistors
marketed for avalanche pulse generator work. May have been
Mullard / Philips, but don\'t remember any circuit details.
Early Tek and HP sampling scopes used an avalanche transistor to drive
the sampler. I think maybe Lumatron did that first.
Years ago, found myself fixing more than a few high power
audio amps and built a simple breakdown tester with a variac,
stepdown transformer, limiting resistor and full wave rectifer.
Got some interesting effects at breakdown, very high frequency
oscillation on the scope. 2n3055 class power devices, normally
quite low frequency use. Interesting effect, perhaps similar
to other weird stuff of the time, like impatt diodes...
Chris
Transistors do all sorts of fun stuff that\'s not on the label.
Zetex makes SOT23 silicon transistors that are designed to avalanche.
As in <1 ns, 300 volts, 60 amps.
Some other tricks:
unclamped inductor flyback avalanche
zero volt saturation
step-recovery effects
stored charge effects
inverse beta
temp-compensated b-e zenering
On 9/6/2023 7:28 PM, John Larkin wrote:
On Wed, 6 Sep 2023 22:56:12 +0000, chrisq <devzero@nospam.com> wrote:
On 9/6/23 22:34, John Larkin wrote:
On Wed, 6 Sep 2023 14:34:12 -0700 (PDT), John Smiht
utube.jocjo@xoxy.net> wrote:
On Wednesday, September 6, 2023 at 2:59:10?PM UTC-5, John Larkin wrote:
On Wed, 6 Sep 2023 19:19:20 +0100, piglet <erichp...@hotmail.com
wrote:
On 06/09/2023 01:04, John Larkin wrote:
Imagine an NPN transistor. Ground the emitter and connect the
collector to some nice positive voltage.
Now pull the base negative, through a current-limiting resistor. What
happens?
If the collector is already positive
That was a stated condition
and pullup resistor is not
extremely high then I think not much detectable will happen even once
the Veb junction breaks down.
\"Detectable\" can include amps or picoamps of currents.
Curious that nobody seems to address this case.
How could the information be used? It seems to have not been needed in the past, yes?
I\'d expect that understanding transistors is a generally good thing to
do. Looking at schematics on the web, it seems like few people do.
If it behaves as I suspect it may, I might have a use for it.
Back in the 60\'s/70\'s there were some germanium transistors
marketed for avalanche pulse generator work. May have been
Mullard / Philips, but don\'t remember any circuit details.
Early Tek and HP sampling scopes used an avalanche transistor to drive
the sampler. I think maybe Lumatron did that first.
Years ago, found myself fixing more than a few high power
audio amps and built a simple breakdown tester with a variac,
stepdown transformer, limiting resistor and full wave rectifer.
Got some interesting effects at breakdown, very high frequency
oscillation on the scope. 2n3055 class power devices, normally
quite low frequency use. Interesting effect, perhaps similar
to other weird stuff of the time, like impatt diodes...
Chris
Transistors do all sorts of fun stuff that\'s not on the label.
Zetex makes SOT23 silicon transistors that are designed to avalanche.
As in <1 ns, 300 volts, 60 amps.
Some other tricks:
unclamped inductor flyback avalanche
zero volt saturation
step-recovery effects
stored charge effects
inverse beta
temp-compensated b-e zenering
They can be used as current-controlled resistors in reverse-saturation
mode, where the collector-emitter resistance becomes generally
proportional to the base current.
On Thursday, 7 September 2023 at 00:28:31 UTC+1, John Larkin wrote:
On Wed, 6 Sep 2023 22:56:12 +0000, chrisq <dev...@nospam.com> wrote:
On 9/6/23 22:34, John Larkin wrote:
On Wed, 6 Sep 2023 14:34:12 -0700 (PDT), John Smiht
utube...@xoxy.net> wrote:
On Wednesday, September 6, 2023 at 2:59:10?PM UTC-5, John Larkin wrote:
On Wed, 6 Sep 2023 19:19:20 +0100, piglet <erichp...@hotmail.com
wrote:
On 06/09/2023 01:04, John Larkin wrote:
Imagine an NPN transistor. Ground the emitter and connect the
collector to some nice positive voltage.
Now pull the base negative, through a current-limiting resistor. What
happens?
If the collector is already positive
That was a stated condition
and pullup resistor is not
extremely high then I think not much detectable will happen even once
the Veb junction breaks down.
\"Detectable\" can include amps or picoamps of currents.
Curious that nobody seems to address this case.
How could the information be used? It seems to have not been needed in the past, yes?
I\'d expect that understanding transistors is a generally good thing to
do. Looking at schematics on the web, it seems like few people do.
If it behaves as I suspect it may, I might have a use for it.
Back in the 60\'s/70\'s there were some germanium transistors
marketed for avalanche pulse generator work. May have been
Mullard / Philips, but don\'t remember any circuit details.
Early Tek and HP sampling scopes used an avalanche transistor to drive
the sampler. I think maybe Lumatron did that first.
Years ago, found myself fixing more than a few high power
audio amps and built a simple breakdown tester with a variac,
stepdown transformer, limiting resistor and full wave rectifer.
Got some interesting effects at breakdown, very high frequency
oscillation on the scope. 2n3055 class power devices, normally
quite low frequency use. Interesting effect, perhaps similar
to other weird stuff of the time, like impatt diodes...
Chris
Transistors do all sorts of fun stuff that\'s not on the label.
Zetex makes SOT23 silicon transistors that are designed to avalanche.
As in <1 ns, 300 volts, 60 amps.
Some other tricks:
unclamped inductor flyback avalanche
zero volt saturation
step-recovery effects
stored charge effects
inverse beta
temp-compensated b-e zenering
You missed noise generation from eb breakdown.
John