Realizations with transistors and capacitors in an emitter follower

[Michael A. Terrell]

And you DumbFuck Imposter think you know it all? Bullshit what makes you think you know above every one fucker? By the way, my news agency said you faked to be me to block me from posting. So you want to be a dictator hugh? Shitstain?

--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

Do you think people can't see you are posting fake messages,
'jackthehammer'? I have never had an aioe.org account, and anyone with
half a brain can see from your headers that you're as phony as you are
stupid.


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From:
Michae A. Terrell <[email protected]>
Newsgroups:
sci.electronics.design, sci.electronics.basics
Subject:
Re: Realizations with transistors and capacitors in an
emitter follower
Date:
Mon, 25 Feb 2008 03:23:07 -0800
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--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

 

[Michael A. Terrell]

Now you're acting like a child. You have some serious issues. Whatever
the hell your fake news agency had told you I wouldn't really bother
to do cuz I don't give a rat's ass about you. I'm taking this
discussion to the basics group, and any further comments/accusations
from you are gonna be deep down my trash bin. I suggest you start by
learning how to spell your name right.

|------||-----|
| DO NOT |
| FEED THE |
| aioe.org |
|jackthehammer|
| TROLL! |
|------||-----|
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||
||
/|\\|/||||//|||/\???\\//\\\\/|?\/
--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

 

[[email protected]]

On Feb 24, 11:21 am, "M. Hamed" <[email protected]>
gave a very clear description of a phenomenon he had
observed. I was wondering if you could answer a probably
easy basic question for me. The clipping that you observed
was related to the transistor turning off? If an NPN transistor,
in an emitter follower configuration say, does not get enough
current, will that alone cause it to turn off? In other words,
perhaps the emitter voltage can go so low that not enough
electron current is drawn through the emitter resistor to
keep it on?

Thanks very much.

 

[John Popelish]

On Feb 24, 11:21 am, "M. Hamed" <[email protected]>
gave a very clear description of a phenomenon he had
observed. I was wondering if you could answer a probably
easy basic question for me. The clipping that you observed
was related to the transistor turning off? If an NPN transistor,
in an emitter follower configuration say, does not get enough
current, will that alone cause it to turn off? In other words,
perhaps the emitter voltage can go so low that not enough
electron current is drawn through the emitter resistor to
keep it on?

An NPN emitter follower turns off if its emitter is not
pulled negatively enough by its load to keep the
base-emitter junction forward biased enough to keep current
flowing through that junction.

When M. Hamed's input signal swung negative, the output
capacitor held the emitter very near the zero signal
voltage, while the base swung negatively. This base swing
eliminated the base-emitter junction forward bias, and
turned the transistor off, leaving only the feeble 5k pull
down resistor to slowly discharge the output capacitor,
while passing a tiny current through the 8 ohm speaker in
series with them.

 

[Jim Thompson]

On Feb 24, 11:21 am, "M. Hamed" <[email protected]>
gave a very clear description of a phenomenon he had
observed. I was wondering if you could answer a probably
easy basic question for me. The clipping that you observed
was related to the transistor turning off? If an NPN transistor,
in an emitter follower configuration say, does not get enough
current, will that alone cause it to turn off? In other words,
perhaps the emitter voltage can go so low that not enough
electron current is drawn through the emitter resistor to
keep it on?

Thanks very much.

Naaah! It was probably the hole current ;-)

...Jim Thompson

 

[[email protected]]

Thanks very much to John and Jim for their kindly, helpful
replies. I only realized belatedly that I should have posted
to a beginner's list (I'm not really up to speed even with
Yahoo groups). Later, after seeing some of the incendiary
and even profane posts, I thought I was going to be rudely
dismissed. So thanks again for the civility and help!

Yours, Lee Corbin

 

[John Popelish]

Thanks very much to John and Jim for their kindly, helpful
replies. I only realized belatedly that I should have posted
to a beginner's list (I'm not really up to speed even with
Yahoo groups). Later, after seeing some of the incendiary
and even profane posts, I thought I was going to be rudely
dismissed. So thanks again for the civility and help!

Much of the rudeness was in fake posts (posted by someone
other than the sender shown) in an attempt to cause trouble.
You always have to watch out for trouble makers who get no
other pleasure from life.

 

[John Larkin]

Thanks very much to John and Jim for their kindly, helpful
replies. I only realized belatedly that I should have posted
to a beginner's list (I'm not really up to speed even with
Yahoo groups). Later, after seeing some of the incendiary
and even profane posts, I thought I was going to be rudely
dismissed. So thanks again for the civility and help!

Yours, Lee Corbin

This newsgroup can be a bit coarse, but it's mild compared to some.
Anyone, no matter how big a jerk or fathead, can post here. So don't
take it personally.

John

 

[John Larkin]

Naaah! It was probably the hole current ;-)

...Jim Thompson

That's a minority opinion.

John

 

[ShamShoon]

When M. Hamed's input signal swung negative, the output
capacitor held the emitter very near the zero signal
voltage, while the base swung negatively. This base swing
eliminated the base-emitter junction forward bias, and
turned the transistor off, leaving only the feeble 5k pull
down resistor to slowly discharge the output capacitor,
while passing a tiny current through the 8 ohm speaker in
series with them.

Hi John. If I may interject here, correct me if I'm wrong. The problem
to me seems more current related than voltage related. The base of the
transistor never goes negative because it's riding on top of the DC
bias signal. The same for the emitter, it never goes to 0, unless you
were talking in small-signal terms. So it seems to me that once the
emitter goes below the bias point, the transistor can not pass the
current in the reverse direction (neglecting the small current passing
in the 5k), so as the output voltage goes very slightly below zero,
the emitter current decreases gradually (by KCL) and that causes Vbe
to decrease (by Ebers-Moll relation), until it's totally zero. So my
understanding here is that in this case, it's the current decrease
that led to forward bias decrease until disconnection.

Does that make sense?

Regards,

 

[Jim Thompson]

That's a minority opinion.

John

<Smirk :->

...Jim Thompson

 

[John Popelish]

Hi John. If I may interject here, correct me if I'm wrong. The problem
to me seems more current related than voltage related.

They are interconnected. Voltage drives current.

The base of the
transistor never goes negative because it's riding on top of the DC
bias signal.

The base voltage swing is driven by the input signal. The
emitter voltage is a result of the current through the
transistor dropping voltage across the emitter load. Once
the base emitter ceases to be forward biased, no current
passes through the collector-emitter path, so the emitter
load is left floating (with the transistor effectively
disconnected from it) and does not follow the base voltage
any more negative.