Re: newbie inquiry:what kills

Keith Messent

I think that there is a difference between those who have been struck
directly by a lightning flash (now deceased!) and those who have been in
the close vicinity of a strike!  I find it just about impossible to
allow that anyone directly struck and burned by a discharge could
possibly survive.  As I reported earlier, it is generally accepted by
Health & Safety authorities that 10 Joules (via PD >230V) through a
vital organ would be lethal!
Keith Messent, Skipton, UK

Show quoted text

----- Original Message -----
From: <adityanewalkar@...>
To: <Electronics_101@...>
Sent: Wednesday, 31 October, 2001 07:17 AM
Subject: [Electronics_101] Re: newbie inquiry:what kills

Think about lightning.  Lightning has millions (10^6) of amperes of
current, several millions of volts of voltage, (sometimes measuring
650 Coulumbs of charge) ... still there are quite a lot of people who
turn up alive even after being hit by lightning.  I think that is
becoz of the fraction of a second the charge passes through the body
of the person.

Re: SOLAR PANEL FOR HOME

Sunantoro

#1084

A very good one, Jo!
Thanks a lot

SUNAN

Show quoted text

-----Original Message-----
	From:	Jonathan Luthje [SMTP:jluthje@...]
	Sent:	Wednesday, October 31, 2001 10:06 AM
	To:	Electronics_101@...
	Subject:	Re: [Electronics_101] SOLAR PANEL FOR HOME

	A good site for this sort of thing is 

	> Does anyone know articles in the internet on technicalities of
solar panel
	> for powering a house in a remote country?
	> Thank you,
	> SUNAN

Re: Digest Number 140

Doug Hale

#1083

Just measure the voltage.

Doug

Jim Purcell wrote:

Show quoted text

Doug,

The electric field is just as easy to observe/quantify as the magnetic
field. Both field exert a physical force. The physical force is measured
as movement against a calibrated spring.
Not inside a capacitor.

Jim

To unsubscribe from this group, send an email to:
Electronics_101-unsubscribe@...

Your use of Yahoo! Groups is subject to

Re: Digest Number 144

J. Pinkston

#1081

I thought some of you might get a chuckle out of this if you haven't already
seen it. Please understand this is a joke. So take it as such & don't bother
sending me corrections.
*


Electricity

     Today's scientific question is:  What in the world is electricity?  And
where does it go after it leaves the toaster? Here is a simple experiment
that will teach you an important electrical lesson:  On a cool, dry day,
scuff your feet along a carpet, then reach your hand into a friend's mouth
and touch one of his dental  fillings.  Did you notice how your friend
twitched violently and cried out in pain?  This teaches us that electricity
can be a very powerful force, but we must never use it to hurt others unless
we need to learn an important electrical lesson. It also teaches us how an
electrical circuit works.  When you scuffed your feet, you picked up batches
of "electrons," which are very small objects that carpet manufacturers weave
into carpet so that they will attract dirt.  The electrons travel through
your blood stream and collect in your finger, where they form a spark that
leaps to your friend's filling, then travel down to his feet and back into
the carpet, thus completing the circuit.
    AMAZING ELECTRONIC FACT:  If you scuffed your feet long enough without
touching anything, you would build up so many electrons that your finger
would explode!  But this is nothing to worry about unless you have
carpeting. Although we modern persons tend to take our electric lights,
radios, mixers, etc. for  granted, hundreds of years ago people did not have
any of these things, which is just as well because there was no place to
plug them in.
    Then along came the first Electrical Pioneer, Benjamin Franklin, who
flew a kite in a lightning storm and received a serious electrical shock.
This proved that lightning was powered by the same force as carpets, but it
also damaged Franklin's brain so severely that he started speaking only in
incomprehensible maxims, such as, "A penny saved is a penny earned."
Eventually he had to be given a job running the post office.
After Franklin came a herd of Electrical Pioneers whose names have become
part of our electrical terminology: Myron Volt, Mary Louise Amp, James Watt,
Bob Transformer, etc. These pioneers  conducted many important electrical
experiments.  Among them, Galvani discovered (this is the truth) that when
he attached two different kinds of metal to the leg of a frog, an electrical
current developed and the frog's leg kicked, even though it was no longer
attached to the frog, which was dead anyway.  Galvani's discovery led to
enormous advances in the field of amphibian medicine.
Today, skilled veterinary surgeons can take a frog that has been seriously
injured or killed, implant pieces of metal in its muscles, and watch it hop
back into the pond -- where it sinks like a stone.
     But the greatest Electrical Pioneer of them all was Thomas Edison, who
was a brilliant inventor despite the fact that he had little formal
education and lived in New Jersey.  Edison's first major invention in 1877
was the phonograph, which could soon be found in thousands of American
homes, where it basically sat until 1923, when the record was invented.  But
Edison's greatest achievement came in 1879 when he invented the electric
company. Edison's design was a brilliant adaptation of the simple electrical
circuit:  the electric company sends electricity through a wire to a
customer, then immediately gets the electricity back through another wire,
then (this is the brilliant part) sends it right back to the customer.  This
means that an electric company can sell a customer the batch of electricity
thousands of times a day and ever
since very few customers take the time to examine their electricity closely.
In fact, the last year any new electricity was made 1937.
     Today, thanks to men like Edison and Franklin, and Galvani's, we
receive almost unlimited benefits from electricity.  For example, in the
past decade scientists have developed the laser, an electronic appliance so
powerful that it can vaporize a bulldozer 2000 yards away, yet so precise
that doctors can use it to perform delicate operations to the human eyeball,
provided they remember to change power setting from "Bulldozer" to
"Eyeball."

Re: Digest Number 140

Jim Purcell

#1082

Doug,

The electric field is just as easy to observe/quantify as the magnetic
field. Both field exert a physical force. The physical force is measured
as movement against a calibrated spring.
Not inside a capacitor.

Jim

Re: Demonizing Hackers

Curtis Sakima

#1080

Well, I just meant that both of us know where the
other stand on the issue.  Plus, I got out what I
wanted to say.

So, being done with that issue, I'm back in the mode
of listening to the jabber of other topics of this
group.

SO many interesting topics are being discussed!!

I'm sorry .... that's what I meant.

Curtis

--- Jim Purcell <jpurcell@...> wrote:

You mean I don't express myself well? :-) Or you we
agree on the issue under siscussion?
=====

*                                           *
*  We guarantee hits to your website        *
*    *
*                                           *


__________________________________________________
Do You Yahoo!?
Make a great connection at Yahoo! Personals.

Re: Digest Number 140

Doug Hale

#1079

The electric field is just as easy to observe/quantify as the magnetic field. Both field exert a physical force. The physical force is measured as movement against a calibrated spring.

The D'arsnval movement in an analog voltmeter actually measures the distance of travel of a force against a calibrated spring. The force is created between a permanent magnet and an electromagnet. The force is directly proportional to the current in the electromagnet. Therefore, it is actually an ameter.

There is another type of meter. It still measures the distance of travel of a force against a calibrated spring. The force is created by the electric field between two charged objects. Theelectric field is directly proportional to the voltage between the two objects. It is, therefore, a volt meter.

Doug

Jim Purcell wrote:

Show quoted text

d,

I mean the field between the two plates.  Magnetic fields induce current
flow and current flow creates magnetic fields.  Doesn't the field between
the two plates have to be magnetic?
The theory books tell us that the field in a capacitor is electrostatic. Unlike
the field around a coil that can be demonstrated to be magnetic, the
field in a capacitor is difficult to test as far as I know.

Jim



To unsubscribe from this group, send an email to:
Electronics_101-unsubscribe@...


Your use of Yahoo! Groups is subject to  

Re: Capacitor - Charge- Energy

Doug Hale

#1078

Mike,
   The Electric Field  is a result of the charge difference on the two plates, simular to the Magnetic field between N and S magnetic poles.

   A magnetic field is the attraction between a N pole and a S pole.
   An electric field is the attraction between a + charge and a - charge.

 This discussion can continue with many oppinions for as long as you all want, but it doesn't change the facts of physics - the charge is on the plates - the field is between the plates and since the dielectric is also between the plates, the field is then in/through the dielectric. This is not my oppinion - this is the facts of physics. If you don't believe me, then go get a physics/electronics book and prove me wrong. Oppinions have little bearing on known physical LAWS.

 If this message is taken as being harsh, then you are free to remove me from the list. I am willing to spend my time on those who want and are willing to learn - not on those that won't.

Doug

Doug

d nixon wrote:

Show quoted text

Sunantoro,

I'm not so sure this is the case.  I'm now leaning towards no electrons stored on the plates, but the "charge" is stored in the field, which is then able to induce a current in the plates when it collapses (when it is "discharged".

-Mike



From: Sunantoro <SUNANTORO@...>
Reply-To: Electronics_101@...
To: "'Electronics_101@...'" <Electronics_101@...>
Subject: RE: [Electronics_101] Capacitor - Charge- Energy
Date: Tue, 30 Oct 2001 11:18:04 +0700

Jim,
When we charge a capacitor, we actually pull-out the electrons from one
plate and at the same time provide more electrons on the other plate. And
then we disconnect the capacitor. The capacitor is now charged. If then we
connect the two leads, using a resistor, the electrons flow  from the
excessed electrons plate to the other. Then the capacitor is being
discharged.
Very easy to explain and to analyse.
In most electrical circuitry, this conventional approach is still good to be
used.
Am I too "FLAT"?
Thanks,
SUNAN

	-----Original Message-----
	From:	Jim Purcell [SMTP:jpurcell@...]
	Sent:	Tuesday, October 30, 2001 10:53 AM
	To:	Electronics_101@...
	Subject:	Re: [Electronics_101] Capacitor - Charge- Energy

	Sunantoro,

		> When people discuss about capacitor, they use "Charge" and
"Energy"
		> interchangeably. This is rather confusing  or ambiguous
(to me).
		> Can we simply change it with "Electrons" which flow and
accumulate in one
		> plate when the opposite plate becomes lack of it
(electrons)?

	Don't think any electrons accumulate on the plates. Where would they
stay.  I'm thinking now that charge is the wrong term to use for the
resulting stored energy. We often say that a capacitor stores a charge, and
it certainly has to be charged, and the text books talk coulombs something
fierce when they get to capacitors. I still can't see the energy in a cap as
stored electrons, that's particles. And fields are not supposed to be
particles, or am I wrong there too.
		>
		> By using this understanding, I believe there is no need to
elaborate further
		> on "Charge" or "Energy",

	Actually, I have a problem with the term energy to describe what is
stored too since energy includes time, i.e. watt seconds, joules.  But the
stored energy is at rest. OR are we talking about the amount of joules it
took to charge... oops, to store the energy.
	Jim

_________________________________________________________________
Get your FREE download of MSN Explorer at 



To unsubscribe from this group, send an email to:
Electronics_101-unsubscribe@...


Your use of Yahoo! Groups is subject to  

Re: Automation

[email protected]

#1077

开云体育

go to altavista.com then look for translate link on the main page (i think?babelfish.altavista.com is the direct link)

?

Imran

Show quoted text

-----Original Message-----
From: Saad Rahman [mailto:saad_75@...]
Sent: Tuesday, October 30, 2001 11:14 AM
To: Electronics_101@...
Subject: RE: [Electronics_101] Automation

How do I get to translate the site? -Saad --- av1a@... wrote: > This site has some great projects like Stepper > controls project for CNC > machine > > (need www.altavista.com > french translator to > read) > > also some PIC programmer PCB schematic .. > > I'm looking for any of the automation projects (& > Fanuc Manuals ;-) > > imran > >? -----Original Message----- > From: iman hermansyah > [mailto:iman_hermansyah@...] > Sent: Monday, October 29, 2001 4:36 AM > To: Electronics_101@... > Subject: Re: [Electronics_101] Automation > > >?? Hi Iask, > >?? I'm interesting in Automation too especially in >?? industrial intsrumentation and Automation,i work > for >?? one of oil company at Instrument division. > >?? iman > >?? --- iasknoone@... wrote: >?? > I work as a Technical Support Engineer in > Automation >?? > Division of a >?? > Turkish Company, Ozdisan Electronics....I would > like >?? > to discuss about >?? > any kind of Automation and Electronics. >?? > >?? > If you have any special projects about > Automation we >?? > may share it. >?? > >?? > >?? > >?? > > > >?? __________________________________________________ >?? Do You Yahoo!? >?? Make a great connection at Yahoo! Personals. >?? > >???????? Yahoo! Groups Sponsor >?????????????? ADVERTISEMENT > > > > >?? To unsubscribe from this group, send an email to: >?? Electronics_101-unsubscribe@... > > > >?? Your use of Yahoo! Groups is subject to the Yahoo! > Terms of Service. > > __________________________________________________ Do You Yahoo!? Make a great connection at Yahoo! Personals.

To unsubscribe from this group, send an email to: Electronics_101-unsubscribe@...

Your use of Yahoo! Groups is subject to the .

Re: SOLAR PANEL FOR HOME

Jonathan Luthje

#1076

A good site for this sort of thing is 

Show quoted text

Does anyone know articles in the internet on technicalities of solar panel
for powering a house in a remote country?
Thank you,
SUNAN

Re: PCI Bus configuration

d nixon

#1075

You know this Internet thing really isn't that difficult to figure out, Saad.  I obtained this in about 10 seconds from a search engine:

From: saad_75@...
Reply-To: Electronics_101@...
To: Electronics_101@...
Subject: [Electronics_101] PCI Bus configuration
Date: Tue, 30 Oct 2001 05:53:39 -0000

Could anyone please provide me the bus pinouts of the PCI. I plan to
make a I/O card than can be attached with the PCI slot.

-Saad

_________________________________________________________________
Get your FREE download of MSN Explorer at

Re: Capacitor - Charge- Energy

d nixon

#1074

Sunantoro,

I'm not so sure this is the case.  I'm now leaning towards no electrons stored on the plates, but the "charge" is stored in the field, which is then able to induce a current in the plates when it collapses (when it is "discharged".

-Mike



From: Sunantoro <SUNANTORO@...>
Reply-To: Electronics_101@...
To: "'Electronics_101@...'" <Electronics_101@...>
Subject: RE: [Electronics_101] Capacitor - Charge- Energy
Date: Tue, 30 Oct 2001 11:18:04 +0700

Jim,
When we charge a capacitor, we actually pull-out the electrons from one
plate and at the same time provide more electrons on the other plate. And
then we disconnect the capacitor. The capacitor is now charged. If then we
connect the two leads, using a resistor, the electrons flow  from the
excessed electrons plate to the other. Then the capacitor is being
discharged.
Very easy to explain and to analyse.
In most electrical circuitry, this conventional approach is still good to be
used.
Am I too "FLAT"?
Thanks,
SUNAN

	-----Original Message-----
	From:	Jim Purcell [SMTP:jpurcell@...]
	Sent:	Tuesday, October 30, 2001 10:53 AM
	To:	Electronics_101@...
	Subject:	Re: [Electronics_101] Capacitor - Charge- Energy

	Sunantoro,

		> When people discuss about capacitor, they use "Charge" and
"Energy"
		> interchangeably. This is rather confusing  or ambiguous
(to me).
		> Can we simply change it with "Electrons" which flow and
accumulate in one
		> plate when the opposite plate becomes lack of it
(electrons)?

	Don't think any electrons accumulate on the plates. Where would they
stay.  I'm thinking now that charge is the wrong term to use for the
resulting stored energy. We often say that a capacitor stores a charge, and
it certainly has to be charged, and the text books talk coulombs something
fierce when they get to capacitors. I still can't see the energy in a cap as
stored electrons, that's particles. And fields are not supposed to be
particles, or am I wrong there too.
		>
		> By using this understanding, I believe there is no need to
elaborate further
		> on "Charge" or "Energy",

	Actually, I have a problem with the term energy to describe what is
stored too since energy includes time, i.e. watt seconds, joules.  But the
stored energy is at rest. OR are we talking about the amount of joules it
took to charge... oops, to store the energy.
	Jim
_________________________________________________________________
Get your FREE download of MSN Explorer at 

Re: Digest Number 140

Jim Purcell

#1073

d,

My attempt here was to experiment with the relationship between the field
and the charge.  With a grounded plate in the middle a field should not be
able to develop (correct?).  If the charge is stored entirely in the field
then this cap would not charge.I think it would depend on where this center plate is connected in relation to
the voltage applied to the outer plates. If this center plate has no reference
to these outer plates it should have no effect. If it does have a potential
relationship to the other plates you might just have half a capacitor.

Jim

Re: Digest Number 140

Jim Purcell

#1072

d,

I mean the field between the two plates.  Magnetic fields induce current
flow and current flow creates magnetic fields.  Doesn't the field between
the two plates have to be magnetic?The theory books tell us that the field in a capacitor is electrostatic. Unlike
the field around a coil that can be demonstrated to be magnetic, the
field in a capacitor is difficult to test as far as I know.

Jim

Re: newbie inquiry

Jonathan Luthje

#1070

开云体育

Jim,

Show quoted text

I don't agree, circuits should ALWAYS be powered down before touching them
In a perfect ideal world this is the way things would be, but this is not a perfect world.
Often one must make adjustments of circuits while they are live.
True - I very rarely disconnect a circuit to do a minor modification (the exception being mains powered circuits - which are ALWAYS isolated) - however for the purpose of this response - being directed at a beginner, I think that this is sound advice to start off with.
?
?Current it the killer
Current and voltage. And the voltage determines the current you draw, that and your body resistance.
- as I have said previously 0.00001A (Or 1 hundred thousandth of an Ampere or 0.01mA) is enough to stop the heart.
If you are very ill. One source claims that the 1 mA level is where you just start feeling the current. Does seem a bit too high, but 0.01 mA just seems way to low to do damage. If it were so I should be dead now. Maybe I am, maybe my ghost is writing this.? :-)
From fingertip to fingertip I would imagine that there is quite a bit of resistance, however from a theoretical point of view, 1MV @ 0.01mA is something that I wouldn't like to play with on the wrong side of a Faraday cage. It's unlikely that a beginner would ever come across this sort of potential - or most field tech's for that matter, however the possibility is still there. For example automotive ignition systems have been known to cause death in rare cases - 75kV @ only 2mA ... so a higher voltage and a lower current could still do some damage.
?

?

Re: Digest Number 140

d nixon

#1071

Jim,

My attempt here was to experiment with the relationship between the field and the charge.  With a grounded plate in the middle a field should not be able to develop (correct?).  If the charge is stored entirely in the field then this cap would not charge.

-Mike



From: Jim Purcell <jpurcell@...>
Reply-To: Electronics_101@...
To: Electronics_101@...
Subject: Re: [Electronics_101] Digest Number 140
Date: Mon, 29 Oct 2001 21:46:09 -0600

d nixon,

Another interesting experiment would be to insert a metal plate inside the
dielectric so that you have: plate-dielectric-plate-dielectric-plate.  The
middle plate (ground it?) should prevent any magnetic field from forming and
you may not be able to charge this capacitor at all.Hmm... Where was the ground when this capacitor was charged. Did that
change. Too many loose ends to predict. My first reaction was that this
would be two series caps, which I think it is, grounding the center plate
threw the monkey wrench.

Jim

_________________________________________________________________
Get your FREE download of MSN Explorer at 

SOLAR PANEL FOR HOME

Sunantoro

#1067

Does anyone know articles in the internet on technicalities of solar panel
for powering a house in a remote country?
Thank you,
SUNAN

Re: Digest Number 140

d nixon

#1068

Sunan,

I mean the field between the two plates.  Magnetic fields induce current flow and current flow creates magnetic fields.  Doesn't the field between the two plates have to be magnetic?

-Mike




From: Sunantoro <SUNANTORO@...>
Reply-To: Electronics_101@...
To: "'Electronics_101@...'" <Electronics_101@...>
Subject: RE: [Electronics_101] Digest Number 140
Date: Tue, 30 Oct 2001 10:43:32 +0700

Mike,
When you say "magnetic field" do you mean it the magnetic field in the
inductance issue?
SUNAN

	-----Original Message-----
	From:	d nixon [SMTP:dnixon9@...]
	Sent:	Tuesday, October 30, 2001 10:16 AM
	To:	Electronics_101@...
	Subject:	Re: [Electronics_101] Digest Number 140

	Another interesting experiment would be to insert a metal plate
inside the dielectric so that you have:
plate-dielectric-plate-dielectric-plate.  The middle plate (ground it?)
should prevent any magnetic field from forming and you may not be able to
charge this capacitor at all.
	-Mike

_________________________________________________________________
Get your FREE download of MSN Explorer at 

Re: Digest Number 146

Michael Carey

#1069

Hey guys (and girls), that point about there being fewer electronics
hobbiests really got to me, how about everyone who considers themselfs a
hobbist also consider writing a web page, I can see no better way of sharing
your experience (no matter how trivial) and also add some info on how they
got started and some of the ideas you use?
naff?

Show quoted text

----- Original Message -----
From: <Electronics_101@...>
To: <Electronics_101@...>
Sent: Wednesday, October 31, 2001 10:01 AM
Subject: [Electronics_101] Digest Number 146



To unsubscribe from this group, send an email to:
Electronics_101-unsubscribe@...


------------------------------------------------------------------------

There are 25 messages in this issue.

Topics in this digest:

      1. RE: Capacitor - Charge- Energy
           From: verhap@...
      2. Re: Cable TV signal amplification
           From: Jim Purcell <jpurcell@...>
      3. RF Antenna question
           From: Mounir Shita <mshita@...>
      4. Re: Capacitor - Charge- Energy
           From: Jim Purcell <jpurcell@...>
      5. Re: capacitors and dielectrics
           From: Jim Purcell <jpurcell@...>
      6. Re: Demonizing Hackers
           From: Curtis Sakima <electronichobbyist@...>
      7. Re: Demonizing Hackers
           From: Jim Purcell <jpurcell@...>
      8. Re: Demonizing Hackers
           From: Curtis Sakima <electronichobbyist@...>
      9. Re: The need to know!
           From: "G Ramasubramani" <grama@...>
     10. RE: RF Antenna question
           From: "Shawn W. McClintock" <kd6oji@...>
     11. Audio Line Level Potentiometer
           From: "Christopher Fetters" <cfetters@...>
     12. Re: Demonizing Hackers
           From: Jim Purcell <jpurcell@...>
     13. Re: The need to know!
           From: Jim Purcell <jpurcell@...>
     14. Re: Audio Line Level Potentiometer
           From: Jim Purcell <jpurcell@...>
     15. RE: RF Antenna question
           From: Mounir Shita <mshita@...>
     16. RE: RF Antenna question
           From: "Shawn W. McClintock" <kd6oji@...>
     17. Re: The need to know!
           From: "G Ramasubramani" <grama@...>
     18. Re: A hopefully simple transistor question
           From: "manifold" <manifold_1@...>
     19. Re: Re: A hopefully simple transistor question
           From: "G Ramasubramani" <grama@...>
     20. Re: Re: A hopefully simple transistor question
           From: Jim Purcell <jpurcell@...>
     21. Re: A hopefully simple transistor question
           From: "manifold" <manifold_1@...>
     22. Re: Re: A hopefully simple transistor question
           From: "G Ramasubramani" <grama@...>
     23. Re: Re: A hopefully simple transistor question
           From: "G Ramasubramani" <grama@...>
     24. RE: Capacitor - Charge- Energy
           From: Sunantoro <SUNANTORO@...>
     25. Re: A hopefully simple transistor question
           From: "manifold" <manifold_1@...>


________________________________________________________________________
________________________________________________________________________

Message: 1
   Date: Tue, 30 Oct 2001 10:22:56 -700
   From: verhap@...
Subject: RE: Capacitor - Charge- Energy

            i think if there is vaccum between the
plates capacitor can't store energy.I don't think so.  As long as their is an electric field between the
plates, there is stored energy.  With a dielectric between the
plates, you can support a larger field, hence store more energy.

Paul


________________________________________________________________________
________________________________________________________________________

Message: 2
   Date: Tue, 30 Oct 2001 11:29:01 -0600
   From: Jim Purcell <jpurcell@...>
Subject: Re: Cable TV signal amplification

Imran,

when i split the cable in two by A/B connector , one for my tv & other for
PC tv tuner card , i started to get noise.
Is there any simple way to amplify these signals.Maybe, but we can't help without more information. Which signal are
we talking about, the video, audio, RF.

I'm assuming RF from the context. There are antenna splitters, that
couple one antenna signal to two inputs. They can usually be had
from any store that carries a variety of TV accessories. If the antenna
consists of 'rabbit ears' however, the result will be less than ideal
even with an amplifier. RF amplifiers are available in well stocked
electronics stores.

Jim



________________________________________________________________________
________________________________________________________________________

Message: 3
   Date: Tue, 30 Oct 2001 12:45:46 -0500
   From: Mounir Shita <mshita@...>
Subject: RF Antenna question

Anyone know about the MICRF102 Micrel part? It's a 300-470MHz transmitter
chip. I don't know anything about RF transmission and I'm just reading the
ad on the current issue of EDN magazine. It says here:

"The MICRF102 QwikRadio transmitter is an easy to use, easy to manufacture
transmitter designed for use with a low cost PCB trace antenna"

This doesn't mean a I can only use a loop back trace on the circuit board to
make the antenna for the chip?

Mounir





[This message contained attachments]



________________________________________________________________________
________________________________________________________________________

Message: 4
   Date: Tue, 30 Oct 2001 11:53:40 -0600
   From: Jim Purcell <jpurcell@...>
Subject: Re: Capacitor - Charge- Energy

werrr,

 i think because of the deformation of the
dielectric  molecular configuration  capacitor stores
charge.
even if there is no dielectric there is air as
dielectric.That idea works until you experience vacuum
capacitors, no dielectric. So the storage medium
seems to be the e.s. field itself. I think I missed
that early on because a field is such a tenuous
thing, at least in my mind it is.

            i think if there is vaccum between the
plates capacitor can't store energy.If that's so then the Collins radio transmitter spent
big bucks on a device that does nothing. I was a
broadcast tech for almost twenty years. Some
transmitters had vacuum capacitors to avoid the
problem of moist air causing arcing.

I am moving to the conclusion that the charge
is stored in this field, nothing new here and
that the plates and dielectric support that
field. If the capacitor is altered in any way
it seems to me that the field will either
collapse or change. But if it changes I
don't buy the idea that the voltage could
rise. That's just my intuition working. No
support evidence.

Now I'm going to wimp out on this discussion.
I am losing interest, mostly because I haven't
seen any  new ideas proffered. I will continue
to read but probably won't reply to the topic
any longer. In my dotage I have a little less
tolerance for perpetual rediscussion of some
issues. I start of with a bang and eventually
become disenchanted.

Jim



________________________________________________________________________
________________________________________________________________________

Message: 5
   Date: Tue, 30 Oct 2001 11:56:59 -0600
   From: Jim Purcell <jpurcell@...>
Subject: Re: capacitors and dielectrics

Doug,

    The main reason I am on this list is because electronics hobbiests
are an endangered spiecies.Do you think so? I hope not. I used to think that radio Hams were too, but
I think that while their ranks may be reduce (maybe they aren't actually)
the ones who remain are just as dedicated. Maybe  Electronics Hobbyists
are like that too.

Jim



________________________________________________________________________
________________________________________________________________________

Message: 6
   Date: Tue, 30 Oct 2001 10:01:57 -0800 (PST)
   From: Curtis Sakima <electronichobbyist@...>
Subject: Re: Demonizing Hackers

Couldn't said it better myself.

I only would like to add that "a lot of times" after
"all hackers get downgraded into criminals" (as
Charles so beautifully puts it)....

LAWS GET LEGISLATED

Laws which (I know ) were probably originally intended
only for the original bad-hacking /cracking act.  But
in the end, serve only to stifle creativity and make
it hard for everyone else.

Curtis


--- Charles <hazenoff@...> wrote:

I don't know how the group got diverted on to thetopic of hacking, other than my invitation to come and
check out my yahoo group, hackerz_n_hickory... but
anyways, to address your fears...

Hackers, for the most part are really good at onething

--------edited simply to reduce length----------

... so don't demonize them..Just sorta like sayingall Christians are like Pat Robertson, or that all
Muslims are like Osama Bin Laden..Generalizations
suck...

So, thank goodness for them <the hackers> ... and ifsomeone does something illegal, treat them like the
crooks they are, I'm down with that..

what I'm not ok with, is everyone who likeselectronics/ computers/ etc, downgrading all hackers
into the realm of criminals...


=====

*                                           *
*  We guarantee hits to your website        *
*    *
*                                           *


__________________________________________________
Do You Yahoo!?
Make a great connection at Yahoo! Personals.



________________________________________________________________________
________________________________________________________________________

Message: 7
   Date: Tue, 30 Oct 2001 12:11:21 -0600
   From: Jim Purcell <jpurcell@...>
Subject: Re: Demonizing Hackers

Curtis,

I only would like to add that "a lot of times" after
"all hackers get downgraded into criminals"If we look at specific acts and punish those I think
we will be better off. Labels are simplistic and often
a convenience that bypasses thinking. They are
sometimes a necessary short hand, but we should
pay attention to what the label means and not
equate reality with the label instead of what it
represents.

Laws which ... were ... intended
..,for  bad-hacking /cracking act.  But
in the end, serve only to stifle creativity and make
it hard for everyone else.As long as people think in terms of the labels instead
of the acts that will continue. We should think,
people who crack computers should be punished.
Not hackers should be punished. It the long run
it will be the acts that bring about court cases.
To object to misuse of terms like hacker is
probably foolish, I have tilted at windmills
before. I am a language freak and it bothers
me to see that many people have little grasp
or effective use of same.

Jim




________________________________________________________________________
________________________________________________________________________

Message: 8
   Date: Tue, 30 Oct 2001 10:30:09 -0800 (PST)
   From: Curtis Sakima <electronichobbyist@...>
Subject: Re: Demonizing Hackers

Jim,

It is really great to be part of this group.  I've
long accepted the fact that I do not express myself in
words very well....however....from what you have
written, you and I seem to be (at least sorta) on the
same page.

Thanks for responding!!

Curtis


--- Jim Purcell <jpurcell@...> wrote:
Curtis,

I only would like to add that "a lot of times"after
"all hackers get downgraded into criminals"If we look at specific acts and punish those I think
we will be better off. Labels are simplistic and
often
a convenience that bypasses thinking. They are
sometimes a necessary short hand, but we should
pay attention to what the label means and not
equate reality with the label instead of what it
represents.

As long as people think in terms of the labels
instead
of the acts that will continue. We should think,
people who crack computers should be punished.
Not hackers should be punished. It the long run
it will be the acts that bring about court cases.
To object to misuse of terms like hacker is
probably foolish, I have tilted at windmills
before. I am a language freak and it bothers
me to see that many people have little grasp
or effective use of same.

Jim



=====

*                                           *
*  We guarantee hits to your website        *
*    *
*                                           *


__________________________________________________
Do You Yahoo!?
Make a great connection at Yahoo! Personals.



________________________________________________________________________
________________________________________________________________________

Message: 9
   Date: Tue, 30 Oct 2001 10:33:53 -0800
   From: "G Ramasubramani" <grama@...>
Subject: Re: The need to know!

Jim,

   It is tough responding to this mail since you seem to have misunderstood
nearly everything I wrote.

Rama
  ----- Original Message -----
  From: Jim Purcell
  To: Electronics_101@...
  Sent: Tuesday, October 30, 2001 9:09 AM
  Subject: Re: [Electronics_101] The need to know!


  Rama,
      Call me Rama.
      Call me anything but late for dinner.

       As you mention, yes - I am referring to space between the plates and
dielectric. I thought that was pretty obvious.

      YOu seemed to be making a distinction between plate distance and
dielectric thickness when you
      said they cold differ. If they differ then you must have air as an
additional dielectric.


            Are you talking leakage due to exceeding dielecric strength?
            Yeah. Maybe discharge is not the correct term, but what the
heck - I am not writing a book :-)

                      I'm sure that the cap will discharge but worse, it
might be
                      Permanently damaged in any but air capacitors. Air is
generally
                      a self healing dielectric.
          If the plates were farther apart than the dielectric thickness
you'd have a mixture of dielectrics, the normal dielectric plus some air (or
vacuum.) I am not sure of more important or less important - both play a
role.
                    Easy to get that from the formula for capacitance as a
function of
                    physical design parameters.  In this formula the plate
distance is the
                    only term on the bottom and dielectric constant is on
top with
                    a constant and plate area. So distance has greater
effect on
                    capacitance. And dielectric thickness is generally
assumed to be
                    the same as plate distance.

  Jim


        Yahoo! Groups Sponsor
              ADVERTISEMENT




  To unsubscribe from this group, send an email to:
  Electronics_101-unsubscribe@...



  Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.




[This message contained attachments]



________________________________________________________________________
________________________________________________________________________

Message: 10
   Date: Tue, 30 Oct 2001 14:31:51 -0600
   From: "Shawn W. McClintock" <kd6oji@...>
Subject: RE: RF Antenna question

Not at all. Although the application this device was designed for utilize a
PCB trace type antenna, it by no means limits you to such an item. There are
of course, several things you must remember with any antenna, PCB, wire or
otherwise.
1) Ensure proper impedance from antenna to transmitter circuit. If need be,
it may be necessary to include some type of  impedance matching circuit.
2) Maintain proper impedance through out your transmission line.
3) The actual antenna be a function of wavelength for the frequency you are
operating at.

You can find out more about antenna design and building by exploring amateur
radio sites on the web. a search on most search engines for antenna design
should get you started.

Shawn

  -----Original Message-----
  From: Mounir Shita [mailto:mshita@...]
  Sent: Tuesday, October 30, 2001 11:46 AM
  To: 'Electronics_101@...'
  Subject: [Electronics_101] RF Antenna question


  Anyone know about the MICRF102 Micrel part? It's a 300-470MHz transmitter
chip. I don't know anything about RF transmission and I'm just reading the
ad on the current issue of EDN magazine. It says here:

  "The MICRF102 QwikRadio transmitter is an easy to use, easy to manufacture
transmitter designed for use with a low cost PCB trace antenna"

  This doesn't mean a I can only use a loop back trace on the circuit board
to make the antenna for the chip?

  Mounir



[This message contained attachments]



________________________________________________________________________
________________________________________________________________________

Message: 11
   Date: Tue, 30 Oct 2001 15:27:00 -0500
   From: "Christopher Fetters" <cfetters@...>
Subject: Audio Line Level Potentiometer

I normally don't do a lot of electronics work but I do a lot of audio work.
I can run a soldering gun... that's about the extent of my expertise.

My church wants to run a line level, balanced output from the back of the
church to the front of the church (65')  Then, after running through a
wall-mounted pot, on to an amp and then to monitor speakers.  The pot is so
that the choir director will have volume control over the signal.

How do I spec the voltage/amperage on the pot? And how would I wire the pot
inline with a balanced signal?  Do you have any suggestions on companies who
might specialize in audio electronics parts?

The board is a professional board operating at +4 dBU (not -10 dBU)

Thanks in advance for the help!!!!

Chris
--------------------------------
Christopher Fetters
President & Founder
Nextivity
(717) 843-4804
(413) 793-1426 Fax
cfetters@...

  -----Original Message-----
  From: G Ramasubramani [mailto:grama@...]
  Sent: Tuesday, October 30, 2001 1:34 PM
  To: Electronics_101@...
  Subject: Re: [Electronics_101] The need to know!


  Jim,

     It is tough responding to this mail since you seem to have
misunderstood nearly everything I wrote.

  Rama
    ----- Original Message -----
    From: Jim Purcell
    To: Electronics_101@...
    Sent: Tuesday, October 30, 2001 9:09 AM
    Subject: Re: [Electronics_101] The need to know!


    Rama,
        Call me Rama.
        Call me anything but late for dinner.

         As you mention, yes - I am referring to space between the plates
and dielectric. I thought that was pretty obvious.

        YOu seemed to be making a distinction between plate distance and
dielectric thickness when you
        said they cold differ. If they differ then you must have air as an
additional dielectric.


              Are you talking leakage due to exceeding dielecric strength?
              Yeah. Maybe discharge is not the correct term, but what the
heck - I am not writing a book :-)

                        I'm sure that the cap will discharge but worse, it
might be
                        Permanently damaged in any but air capacitors. Air
is generally
                        a self healing dielectric.
            If the plates were farther apart than the dielectric thickness
you'd have a mixture of dielectrics, the normal dielectric plus some air (or
vacuum.) I am not sure of more important or less important - both play a
role.
                      Easy to get that from the formula for capacitance as a
function of
                      physical design parameters.  In this formula the plate
distance is the
                      only term on the bottom and dielectric constant is on
top with
                      a constant and plate area. So distance has greater
effect on
                      capacitance. And dielectric thickness is generally
assumed to be
                      the same as plate distance.

    Jim



    To unsubscribe from this group, send an email to:
    Electronics_101-unsubscribe@...



    Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.



        Yahoo! Groups Sponsor
              ADVERTISEMENT




  To unsubscribe from this group, send an email to:
  Electronics_101-unsubscribe@...



  Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.



[This message contained attachments]



________________________________________________________________________
________________________________________________________________________

Message: 12
   Date: Tue, 30 Oct 2001 14:54:24 -0600
   From: Jim Purcell <jpurcell@...>
Subject: Re: Demonizing Hackers

Curtis,

It is really great to be part of this group.  I've
long accepted the fact that I do not express myself in
words very well....however....from what you have
written, you and I seem to be (at least sorta) on the
same page.You mean I don't express myself well? :-) Or you we
agree on the issue under siscussion?

Jim



________________________________________________________________________
________________________________________________________________________

Message: 13
   Date: Tue, 30 Oct 2001 14:56:56 -0600
   From: Jim Purcell <jpurcell@...>
Subject: Re: The need to know!

Rama,

   It is tough responding to this mail since you seem to have
misunderstood nearly everything I wrote.I have a way of doing that. Partly because I am a literalist. I take
what someone says/writes at face value unless 'he couldn't mean that'.

Jim


[This message contained attachments]



________________________________________________________________________
________________________________________________________________________

Message: 14
   Date: Tue, 30 Oct 2001 15:00:24 -0600
   From: Jim Purcell <jpurcell@...>
Subject: Re: Audio Line Level Potentiometer

Chris,

My church wants to run a line level, balanced output from the back of
the church to the front of the church (65')  Then, after running
through a wall-mounted pot, on to an amp and then to monitor
speakers.  The pot is so that the choir director will have volume
control over the signal.
 How do I spec the voltage/amperage on the pot?

A gain control at speaker level would be better. I haven't done PA
work in a very long time but I can't recall seeing line impedance gain
controls as commonly available. You might check with a local sound
company to see if they are available.

Jim
[This message contained attachments]



________________________________________________________________________
________________________________________________________________________

Message: 15
   Date: Tue, 30 Oct 2001 16:06:35 -0500
   From: Mounir Shita <mshita@...>
Subject: RE: RF Antenna question

Actually, a PCB trace antenna sounds like a perfect fit for my project.
However, the circuit will be going on my cat. On the datasheet it says that
this type on an antenna is very directional. How true is that? And is there
a way around that problem.

Hope the questions aren't to stupid. I'm very illiterate when it comes to
RF.

Mounir

-----Original Message-----
From: Shawn W. McClintock [mailto:kd6oji@...]
Sent: Tuesday, October 30, 2001 12:32 PM
To: Electronics_101@...
Subject: RE: [Electronics_101] RF Antenna question


Not at all. Although the application this device was designed for utilize a
PCB trace type antenna, it by no means limits you to such an item. There are
of course, several things you must remember with any antenna, PCB, wire or
otherwise.
1) Ensure proper impedance from antenna to transmitter circuit. If need be,
it may be necessary to include some type of  impedance matching circuit.
2) Maintain proper impedance through out your transmission line.
3) The actual antenna be a function of wavelength for the frequency you are
operating at.

You can find out more about antenna design and building by exploring amateur
radio sites on the web. a search on most search engines for antenna design
should get you started.

Shawn


-----Original Message-----
From: Mounir Shita [mailto:mshita@...]
Sent: Tuesday, October 30, 2001 11:46 AM
To: 'Electronics_101@...'
Subject: [Electronics_101] RF Antenna question


Anyone know about the MICRF102 Micrel part? It's a 300-470MHz transmitter
chip. I don't know anything about RF transmission and I'm just reading the
ad on the current issue of EDN magazine. It says here:

"The MICRF102 QwikRadio transmitter is an easy to use, easy to manufacture
transmitter designed for use with a low cost PCB trace antenna"

This doesn't mean a I can only use a loop back trace on the circuit board to
make the antenna for the chip?

Mounir




Yahoo! Groups Sponsor

ADVERTISEMENT

<
37:HM/A=763352/R=0/*>

<
l/S=1706058037:HM/A=763352/rand=680424608>

To unsubscribe from this group, send an email to:
Electronics_101-unsubscribe@...



Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service
<> .




[This message contained attachments]



________________________________________________________________________
________________________________________________________________________

Message: 16
   Date: Tue, 30 Oct 2001 15:41:53 -0600
   From: "Shawn W. McClintock" <kd6oji@...>
Subject: RE: RF Antenna question

Only too glad to help. Yes, the PCB trace antenna is directional.. however,
for short distances of say under 300 ft. this is not very apparent. so if
the cat is in the house, you shouldnt have too many problems. if the
transmiter output is 50 ohm, you can use a simple loop antenna that would
fit inside the cat's collar. all this would require is a 4:1 matching
transformer because a loop antenna is 300 ohm, the matching transformer is
very easy to build or, if you want, buy at many electronics stores. These
are commonly known as CATV adaptors, for older sets that have screw
terminals for the flat twin lead type antenna cable to be able to use the
new coax based devices. Many TV shops have them and may give you one for the
asking, they can also be found at Wal-Mart, ect..

Shawn

  -----Original Message-----
  From: Mounir Shita [mailto:mshita@...]
  Sent: Tuesday, October 30, 2001 3:07 PM
  To: 'Electronics_101@...'
  Subject: RE: [Electronics_101] RF Antenna question


  Actually, a PCB trace antenna sounds like a perfect fit for my project.
However, the circuit will be going on my cat. On the datasheet it says that
this type on an antenna is very directional. How true is that? And is there
a way around that problem.

  Hope the questions aren't to stupid. I'm very illiterate when it comes to
RF.

  Mounir



[This message contained attachments]



________________________________________________________________________
________________________________________________________________________

Message: 17
   Date: Tue, 30 Oct 2001 13:48:36 -0800
   From: "G Ramasubramani" <grama@...>
Subject: Re: The need to know!

Jim,

     Yeah. I understood that about you.

Rama
  ----- Original Message -----
  From: Jim Purcell
  To: Electronics_101@...
  Sent: Tuesday, October 30, 2001 12:56 PM
  Subject: Re: [Electronics_101] The need to know!


  Rama,
       It is tough responding to this mail since you seem to have
misunderstood nearly everything I wrote.
  I have a way of doing that. Partly because I am a literalist. I take what
someone says/writes at face value unless 'he couldn't mean that'.
  Jim
        Yahoo! Groups Sponsor
              ADVERTISEMENT




  To unsubscribe from this group, send an email to:
  Electronics_101-unsubscribe@...



  Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.




[This message contained attachments]



________________________________________________________________________
________________________________________________________________________

Message: 18
   Date: Tue, 30 Oct 2001 22:15:54 -0000
   From: "manifold" <manifold_1@...>
Subject: Re: A hopefully simple transistor question

Yes, excellent advice.  Here are a couple of points for general
knowledge.

The gain of the transistor (beta) is the given in the data sheets as
either beta or hfe.  That gain is measured in the linear operating
region or in other words where it is highest.  Beta is collector
current divided by base current.  As the transistor nears saturation
the beta is greatly reduced.  For switching applications where the
transistor must be on "hard" a general rule is that the beta is
reduced by a factor of 10.  You can get away with a factor of 5 in
low power applications, or at least I have done it.

Saturation can be measured.  When the relay is energized, measure the
emitter to collector voltage.  It should be near 0.1V or so depending
on the transistor.  If it is much higher, then too much power is
dissipated in the transistor.  The power should be dissipated in the
load not the switching element.  To resolve this, increase the base
current or select a transistor with better specifications.

Now you can see why FETs are often used for switching applications.
There is no current flow into the gate.  FETs have there own set of
problems but that's another topic.  For your particular application,
a logic level FET should work very well.

Protect the transistor.  In relay applications, be sure to put a
reversed diode across the relay coil and very close to the relay.
The diode is standard practice on all relay circuits and is even
included in some relays.  That is one reason why relay coils often
have a (+) and (-) mark on the coil leads.  When the relay is shut
off the coil field collapses and creates an inductive 'kick' that can
reach hundreds of volts.  That kick can break down the transistor
juctions causing a fast or slow failure.  It may work alright today
but...

Hope that helps.
(P.S. the math isn't really all that bad for a single transistor)

--- In Electronics_101@y..., mehdi Rostami <mrostamy@y...> wrote:

Hi Jonathan,
I was looking at the specifications of the BF469 and well, thetransistor is not really intended for use as a switch, although I
suppose any transistor be used as a switch as long as some care is
taken. It happens that you have not told us what is the relays
minimum operating current, at its specified voltage drive. The
transistor you used has a peak Colector current of 100mA. I would
suggest That you use a more common but more robust transistor, like a
TIP31 or even a  2N2222, the latter dealing well with 300mA (500mA
limit), and being very suitable for switching applications as well as
high frequency switching, PWM, etc. Please bear in mind that the
transistors with BF prefix are usually signal transistors for audio
and video. In this case you are using a "high voltage NPN intended
for class B video applications"
One other question, why did you put the realy at the emitter? Themost usual and correct topology is the emmiter connected to ground
and the relay in the colector. I think that this is the first
modifiction to do...put the relay in the collector!
In order to saturate a transistor, you need enough current, so itis not directly a question of the voltage aplied to the base,
referred to the emmiter. With a voltage of 0.6V between the base and
emitter a transistor would start to turn on, so 6 Volt is more that
enough to get the transistor saturated. If you are really interested
in the maths behind the transistor design it???s really very easy, but
you would have to know the relays impedance, its operating voltage,
the transistors saturation VCE, and of course the voltages available.
Good luck and keep us informed!


Jonathan Luthje <jluthje@p...> wrote: Hi Guys,
    I see there a few knowledgeable people getting around thegroup, so I'm
hoping one or more of you can help me. I am trying to use atransistor
(BF469) to drive a relay using an MPU - the problem being itdoesn't seem to
be switching. It would appear to me that the transistor isn'tsaturating.

I have 2 power rails with a common ground (+6v regulated & +12vunreg) - I
am applying 6v to the base via a 1.6k resistor, collector isgetting 12v
unreg., emitter is (of course) attached to the relay coil with adiode
across it - the other end of the coil going to ground. If I shortout the
1.6k resistor, the relay "flutters" very weakly - indicating to methat the
12v coil is only receiving 6v. If I short out Base/Collector itswitches
hard on.

Can I saturate an NPN trannie w/6v on base to drive a 12Vcollector/emitter?
Do I need to apply a bias resistor somewhere in there?

Thanks in advance for any help,


Regards,


J0n





Yahoo! Groups SponsorADVERTISEMENT
finalURL= "
1706058037:HM/A=799560/R=0/*
overstock3+shopping:dmad/M=168643.1620686.3168692.1261774/D=egroupweb/
S=1706058037:HM/A=799560/R=1/1001897855+
tp://www.overstock.com/rmi-framed-url/
bin/d2.cgi%3Fcid=12715";var flashFileURL = "
/flash/misc/osyahooswf_0925.swf";var noFlashImg
= "; on
error resume next Sub banner_click_lrec_FSCommand(ByVal command,
ByVal args)  call banner_click_lrec_DoFSCommand(command, args)end sub
















function makeNewWindow(url) {var newWindow = window.open(url); }
To unsubscribe from this group, send an email to:
Electronics_101-unsubscribe@y...



Your use of Yahoo! Groups is subject to the Yahoo! Terms ofService.



---------------------------------
Do You Yahoo!?
Get your free Yahoo! address at Yahoo! Mail: UK or IE.

________________________________________________________________________
________________________________________________________________________

Message: 19
   Date: Tue, 30 Oct 2001 14:19:11 -0800
   From: "G Ramasubramani" <grama@...>
Subject: Re: Re: A hopefully simple transistor question

(P.S. the math isn't really all that bad >> for a single transistor)
Even when you start applying negative feedback? :-)

Rama


[This message contained attachments]



________________________________________________________________________
________________________________________________________________________

Message: 20
   Date: Tue, 30 Oct 2001 16:37:57 -0600
   From: Jim Purcell <jpurcell@...>
Subject: Re: Re: A hopefully simple transistor question

Rama,

(P.S. the math isn't really all that bad >> for a singletransistor) Even when you start applying negative feedback? :-)By the time you get that far you have also had to contend with the
effect of following stages. The gain of a stage is usually never as good
ad the beta, i.e. current gain. Stage gain is roughly equivalent to  Rc
|| R load divided by the emitter AC resistance. (the || is shorthand for
in parallel with).  In most cases you can ignore the r(sub)E unless the
emitter R is low or you need a more accurate figure.

Jim


[This message contained attachments]



________________________________________________________________________
________________________________________________________________________

Message: 21
   Date: Tue, 30 Oct 2001 22:41:27 -0000
   From: "manifold" <manifold_1@...>
Subject: Re: A hopefully simple transistor question

How about sensitivity analysis!  Arrggg!  "Kenneth, what is the Early
voltage?!"


--- In Electronics_101@y..., "G Ramasubramani" <grama@a...> wrote:
(P.S. the math isn't really all that bad >> for a singletransistor)


Even when you start applying negative feedback? :-)

Rama

________________________________________________________________________
________________________________________________________________________

Message: 22
   Date: Tue, 30 Oct 2001 14:41:34 -0800
   From: "G Ramasubramani" <grama@...>
Subject: Re: Re: A hopefully simple transistor question

Don't tell me. You have never heard of rhetoric also.
  ----- Original Message -----
  From: Jim Purcell
  To: Electronics_101@...
  Sent: Tuesday, October 30, 2001 2:37 PM
  Subject: Re: [Electronics_101] Re: A hopefully simple transistor question


  Rama,
    >>(P.S. the math isn't really all that bad >> for a single transistor)
Even when you start applying negative feedback? :-)
  By the time you get that far you have also had to contend with the effect
of following stages. The gain of a stage is usually never as good ad the
beta, i.e. current gain. Stage gain is roughly equivalent to  Rc || R load
divided by the emitter AC resistance. (the || is shorthand for in parallel
with).  In most cases you can ignore the r(sub)E unless the emitter R is low
or you need a more accurate figure.
  Jim
        Yahoo! Groups Sponsor
              ADVERTISEMENT




  To unsubscribe from this group, send an email to:
  Electronics_101-unsubscribe@...



  Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.




[This message contained attachments]



________________________________________________________________________
________________________________________________________________________

Message: 23
   Date: Tue, 30 Oct 2001 14:43:33 -0800
   From: "G Ramasubramani" <grama@...>
Subject: Re: Re: A hopefully simple transistor question

Actually, if you work with the AC picture of the circuit, replacing the
transistor in the circuit with the equivalent current and voltage sources,
it is as simple as applying Kirchoffs laws.

Rama
  ----- Original Message -----
  From: manifold
  To: Electronics_101@...
  Sent: Tuesday, October 30, 2001 2:41 PM
  Subject: [Electronics_101] Re: A hopefully simple transistor question


  How about sensitivity analysis!  Arrggg!  "Kenneth, what is the Early
  voltage?!"


  --- In Electronics_101@y..., "G Ramasubramani" <grama@a...> wrote:
  > >>(P.S. the math isn't really all that bad >> for a single
  transistor)
  >
  >
  > Even when you start applying negative feedback? :-)
  >
  > Rama


        Yahoo! Groups Sponsor
              ADVERTISEMENT




  To unsubscribe from this group, send an email to:
  Electronics_101-unsubscribe@...



  Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.



[This message contained attachments]



________________________________________________________________________
________________________________________________________________________

Message: 24
   Date: Wed, 31 Oct 2001 06:02:43 +0700
   From: Sunantoro <SUNANTORO@...>
Subject: RE: Capacitor - Charge- Energy

A precise explanation, Paul.
Thanks,
SUNAN

-----Original Message-----
From: verhap@... [SMTP:verhap@...]
Sent: Tuesday, October 30, 2001 5:23 PM
To: Electronics_101@...
Subject: RE: [Electronics_101] Capacitor - Charge- Energy

            i think if there is vaccum between the
plates capacitor can't store energy.I don't think so.  As long as their is an electric field between the
plates, there is stored energy.  With a dielectric between the plates, you
can support a larger field, hence store more energy.
Paul


________________________________________________________________________
________________________________________________________________________

Message: 25
   Date: Tue, 30 Oct 2001 23:01:20 -0000
   From: "manifold" <manifold_1@...>
Subject: Re: A hopefully simple transistor question

See, I told you the math wasn't that hard.

There is a method called Driving Point Impedance Analysis that makes
AC analysis easier.  Most of the analysis can be done in your head.

--- In Electronics_101@y..., "G Ramasubramani" <grama@a...> wrote:
Actually, if you work with the AC picture of the circuit, replacingthe transistor in the circuit with the equivalent current and voltage
sources, it is as simple as applying Kirchoffs laws.



________________________________________________________________________
________________________________________________________________________



Your use of Yahoo! Groups is subject to 

Re: newbie inquiry

Jim Purcell

#1066

Jonathan,

I don't agree, circuits should ALWAYS be powered down before touching them
In a perfect ideal world this is the way things would be, but this is not a perfect world.
Often one must make adjustments of circuits while they are live.
- even if they have a maximum potential of 5v / 1mA - if it can't or won't kill you - the circuit should be disconnected anyway as it avoids damage to your circuit.
I once worked for a medical electronics company and we had to install and remove pc boards in a microprocessor based unit, (8080 chip) with the power on. Amazingly we never killed a component doing that. I was flabbergasted the first time I saw another tech doing that. At a TV station a few years before a non tech (even though he had a first phone FCC license) got tired of the cartridge video tape machine always acting up so he pulled out a board and jammed it back in and it cost 10000 for the RCA engineer to come to the TV station and fix it. I couldn't believe it, he had no solder suckers, we removed IC's with solder wick and pliars. It took a week for the repair.
?Current it the killer
Current and voltage. And the voltage determines the current you draw, that and your body resistance.
- as I have said previously 0.00001A (Or 1 hundred thousandth of an Ampere or 0.01mA) is enough to stop the heart.
If you are very ill. One source claims that the 1 mA level is where you just start feeling the current. Does seem a bit too high, but 0.01 mA just seems way to low to do damage. If it were so I should be dead now. Maybe I am, maybe my ghost is writing this.? :-)
The key is whether or not the current flows through the heart. If you are unavoidable working with high voltage, always wear long pants, rubber soled shoes, and keep one hand in your pocket - this lessens the likelyhood of the current going through the heart.
I can agree with that. The old one handed rule.
?Gloves will NOT protect you - I wouldn't feel save touching a 110V circuit with rubber gloves, letalone a HIGH voltage circuit.
Rubber gloves are as thick as the insulation on some 120 V wire, probably not as good an insulator, or maybe it is. Point is that there's such a thing as being too cautious, over caution usually resuts from fear. If you're afraid, just leave it alone.?
?

Jim