Maker Pro
Maker Pro

Turn Your Power Supply into an Ohmmeter - It's Free!

  • Thread starter Watson A.Name - 'Watt Sun'
  • Start date
W

Watson A.Name - 'Watt Sun'

Jan 1, 1970
0
I believe everyone on this newsgroup can isolate each of the terms
algebraically. What is your point? What don't you agree with? What is
incorrect? Be specific. Ratch

I think the point of everyone here is that you're being pedantic,
pointing out something that has no real relation to the topic being
discussed.


--
@@F@r@o@m@@O@r@a@n@g@e@@C@o@u@n@t@y@,@@C@a@l@,@@w@h@e@r@e@@
###Got a Question about ELECTRONICS? Check HERE First:###
http://users.pandora.be/educypedia/electronics/databank.htm
My email address is whitelisted. *All* email sent to it
goes directly to the trash unless you add NOSPAM in the
Subject: line with other stuff. alondra101 <at> hotmail.com
Don't be ripped off by the big book dealers. Go to the URL
that will give you a choice and save you money(up to half).
http://www.everybookstore.com You'll be glad you did!
Just when you thought you had all this figured out, the gov't
changed it: http://physics.nist.gov/cuu/Units/binary.html
@@t@h@e@@a@f@f@l@u@e@n@t@@m@e@e@t@@t@h@e@@E@f@f@l@u@e@n@t@@
 
W

Watson A.Name - 'Watt Sun'

Jan 1, 1970
0
After all that I still can't get my ohmmeter to work as a power supply!!!

Tsk-tsk! Siwwy wabbit! You have to unscrew the back of the meter,
and remove the 9V battery, then connect the wires to it! Simple!

--
@@F@r@o@m@@O@r@a@n@g@e@@C@o@u@n@t@y@,@@C@a@l@,@@w@h@e@r@e@@
###Got a Question about ELECTRONICS? Check HERE First:###
http://users.pandora.be/educypedia/electronics/databank.htm
My email address is whitelisted. *All* email sent to it
goes directly to the trash unless you add NOSPAM in the
Subject: line with other stuff. alondra101 <at> hotmail.com
Don't be ripped off by the big book dealers. Go to the URL
that will give you a choice and save you money(up to half).
http://www.everybookstore.com You'll be glad you did!
Just when you thought you had all this figured out, the gov't
changed it: http://physics.nist.gov/cuu/Units/binary.html
@@t@h@e@@a@f@f@l@u@e@n@t@@m@e@e@t@@t@h@e@@E@f@f@l@u@e@n@t@@
 
W

Watson A.Name - 'Watt Sun'

Jan 1, 1970
0
Exactly. It is un-eff-ing believable how some people just love
to snipe.

I wonder how many of the "snipers" ever had to brew a meter shunt?
You can use the "Watson ohmmeter" for that - and, as another
poster mentioned - toss your Fluke in the dustbin. :)

Hey, I like that.. It has a nice ring to it: "Watson Ohmmeter".

One of the maintenance guys at work gave me a Fluke 23 meter which is
just a yellow cased version of the 73, I believe. Said he sent it to
Fluke but they sent it back because it it was beyond repair or it
would cost more than a new meter. He might have done something really
stoopid like set it to the ohms range and put it on the 480VAC. In
any case, the display comes on, but nothing happens when the test
leads are connected to a V source. Apparently something major has
been zapped. It's been laying around at work for a couple years, it
probably oughtta be tossed in the trash can. The case is kind of
grubby so it's not worth saving for the case. Maybe I should give it
to the theater dept to use as a prop.

Recently the theater guy came over and asked our help desk lady for a
dozen telephone handsets and curly cords. She asked him what they
were going to do with them. He said they were going to use them as
props in a play, the actors would be dancing around with the handset
and the curly cord on stage. He said they would give them back after
the play was over.

Maybe they were going to imitate that Sprint guy: "Can you hear me
now?"...


--
@@F@r@o@m@@O@r@a@n@g@e@@C@o@u@n@t@y@,@@C@a@l@,@@w@h@e@r@e@@
###Got a Question about ELECTRONICS? Check HERE First:###
http://users.pandora.be/educypedia/electronics/databank.htm
My email address is whitelisted. *All* email sent to it
goes directly to the trash unless you add NOSPAM in the
Subject: line with other stuff. alondra101 <at> hotmail.com
Don't be ripped off by the big book dealers. Go to the URL
that will give you a choice and save you money(up to half).
http://www.everybookstore.com You'll be glad you did!
Just when you thought you had all this figured out, the gov't
changed it: http://physics.nist.gov/cuu/Units/binary.html
@@t@h@e@@a@f@f@l@u@e@n@t@@m@e@e@t@@t@h@e@@E@f@f@l@u@e@n@t@@
 
R

Ratch

Jan 1, 1970
0
Ratch said:
I think the point of everyone here is that you're being pedantic,
pointing out something that has no real relation to the topic being
discussed.
Good. You finally gave a valid reason for your gripe and did not deny
my "factoid". I can understand and appreciate your concern and irritation.
However, these threads are not just read and appreciated by you , I, and a
select few. There are plenty of lurkers who don't mind learning something,
and inserting ancillary facts into a discussion is not beyond what is
normally done here. Look at how some of the other threads have morphed.
Anyway, I don't think I was out of line in pointing out that Ohm's law is
usually used as a misnomer. The choice to keep on doing so is up to the
individual. Ratch
 
C

Chuck Harris

Jan 1, 1970
0
Hi Ratch,

It is not as simple as all that. E = Ri has been called "Ohm's" law for
as far back as my reference library goes, which is 1907. I cannot
verify, but I would presume that the origin of the the alleged misuse
goes even further back.

In any case, this relation has been called Ohm's law for so long, that
regardless of its origin, it *is* Ohm's law. To try and change the
common usage at this late date would just needlessly confuse the issue.

As a possible explanation for the term Ohm's law, consider that the unit
of resistivity has been called the ohm, as a tribute to Georges Ohm.

The equation that describes the relationship of resistance, voltage,
and current would naturally be called the law of resistance, or the
law of the ohm. It wouldn't take much to morph that to ohm's law.

-Chuck, WA3UQV
 
Å

ånønÿmøu§

Jan 1, 1970
0
When I need to power some of my smaller creations I use an ohmmeter as a
power supply...
Hummm ... I have actually seen CMOS circuits run! With just test equipment attached and the power supply off!
 
I

Ian Stirling

Jan 1, 1970
0
In sci.electronics.misc Lizard Blizzard said:
But, But.. Doesn't the FR in FR4 mean flame resistant? If so, how
could it burn? Char?

Hmm, probably, yes.
It went out when the source of 2000V (at moderate current) was turned off.

--
http://inquisitor.i.am/ | mailto:[email protected] | Ian Stirling.
---------------------------+-------------------------+--------------------------
Lord, grant me the serenity to accept that I cannot change, the
courage to change what I can, and the wisdom to hide the bodies
of those I had to kill because they pissed me off. - Random
 
M

Mike Russell

Jan 1, 1970
0
Chuck said:
Hi Ratch,

It is not as simple as all that. E = Ri has been called "Ohm's" law
for
as far back as my reference library goes, which is 1907. I cannot
verify, but I would presume that the origin of the the alleged misuse
goes even further back.

A friend of mine took an electronics class at a local JC, and he learned
"Ohm's Three Laws": E=IR, I=E/R, and R = E/I.

--

Mike Russell
http://www.curvemeister.com
http://www.zocalo.net/~mgr
http://geigy.2y.net
 
B

buck rojerz

Jan 1, 1970
0
I belive that you are missing the point. The resistance (or
impedance)
formula V=IR (or V=IZ), describes the describes the interaction of
resistance (impedance), voltage, and current. While correct and true
in all cases, those formulas are NOT Ohm's law, and it is wrong to
call them that. As shown in the second link I gave, Ohm's law is a
property of resistive linearity in a material. Just as the specific
gravity of a material is a property. If it conforms to Ohm's law, it
is ohmic. Otherwise it is nonohmic. Ratch

What the heck is "nonohmic"? Is this a word you just made up? I have been
an electronis tech for 30+ years and thats a new one on me. It all doesn't
matter. Wether it is inductance, capacitive impedance, a thermistor, a
varistor, or what ever. Ohm's law still stands firm. For changing
"impedance" or fixed resistance. At any moment in time, there is a certain
resistance(impedance), a certain voltage and a certain current and ohm's
law always applies. Even in a combined circuit of capacitance and
inductance with an appplied frequency signal. At 1 instantaneous moment,
there is a vectored impedance and associated voltage and current. It is a
law of physics and there is no getting around it no matter what you call
it. A rose is a rose is a rose.
Here are the formulae and you believe what you will.
 
F

Frank Bemelman

Jan 1, 1970
0
Chuck Harris said:
Hi Ratch,

It is not as simple as all that. E = Ri has been called "Ohm's" law for
as far back as my reference library goes, which is 1907. I cannot
verify, but I would presume that the origin of the the alleged misuse
goes even further back.

In any case, this relation has been called Ohm's law for so long, that
regardless of its origin, it *is* Ohm's law. To try and change the
common usage at this late date would just needlessly confuse the issue.

As a possible explanation for the term Ohm's law, consider that the unit
of resistivity has been called the ohm, as a tribute to Georges Ohm.

The equation that describes the relationship of resistance, voltage,
and current would naturally be called the law of resistance, or the
law of the ohm. It wouldn't take much to morph that to ohm's law.

Let's go all nuts and talk about ohmistance & ohmistors from now on ;)
 
W

Watson A.Name - 'Watt Sun'

Jan 1, 1970
0
Hmm, probably, yes.
It went out when the source of 2000V (at moderate current) was turned off.

Eeww!! StinkCity!

--
@@F@r@o@m@@O@r@a@n@g@e@@C@o@u@n@t@y@,@@C@a@l@,@@w@h@e@r@e@@
###Got a Question about ELECTRONICS? Check HERE First:###
http://users.pandora.be/educypedia/electronics/databank.htm
My email address is whitelisted. *All* email sent to it
goes directly to the trash unless you add NOSPAM in the
Subject: line with other stuff. alondra101 <at> hotmail.com
Don't be ripped off by the big book dealers. Go to the URL
that will give you a choice and save you money(up to half).
http://www.everybookstore.com You'll be glad you did!
Just when you thought you had all this figured out, the gov't
changed it: http://physics.nist.gov/cuu/Units/binary.html
@@t@h@e@@a@f@f@l@u@e@n@t@@m@e@e@t@@t@h@e@@E@f@f@l@u@e@n@t@@
 
W

William Hayes

Jan 1, 1970
0
Its one of those connie current things getting ronnie resistor ... hot. :)
 
W

William Hayes

Jan 1, 1970
0
Sofie said:
Sir Charles W. Shults III:
That is a good in depth, overly complicated, answer but not the one I was
looking for

There was these two Engineers.... leaving the work place, they were headed
home.
They left the building headed out to the parking lot when the first engineer
stopped at a brand new 10 speed bike,
bent over and unlocked it. The second engineer looked at the first and
said, "Hey, I didn't know you got a new bike."
The first engineer started recounting his experience at getting the new
bike, "Yeah, I was out jogging my 1/2 block down the street when a lady on
this ten speed bike came by. She stopped. Got off the bike. Took all her
clothes off. Stood in front of me and said to me that I could have anything
I wanted." The second engineer thought for a moment and replied, " Yeah,
good choice, I don't think you'd fit into any girlie clothes, either."

So, now that we've had a nice discussion about ohm's law, explain that
fangled volt/amps rating on stuff.
I'm sure someone will note it is "nonohmic" somewhere... :)
 
W

William Hayes

Jan 1, 1970
0
Mark Mcmillan said:
After all that I still can't get my ohmmeter to work as a power supply!!!

Probably an analog meter multimeter.
You'll have to get with the program and buy a digital one. :) :)
 
W

William Hayes

Jan 1, 1970
0
Mark Jones said:
Oh well it might have been funnier with the actual drawing. Man I need to
get out more... :)

I understand there are occasionally sightings of 'wild bike riding' women
when our sorts take to jogging 1/2 a block.
:) :)

(I haven't tried jogging a full block ... my luck, I'd run into wild cement
truck driving women ... )
 
W

William Hayes

Jan 1, 1970
0
Mike Russell said:
A friend of mine took an electronics class at a local JC, and he learned
"Ohm's Three Laws": E=IR, I=E/R, and R = E/I.

That'll teach me to let my education lapse.

I remember Charles Coulomb, and how charged objects have force; F ~
(q*q1)/d^2
which relates in some small way to an electric field having force, magnitude
and direction.
Giving the Electric potential equaling the work done (force, magnitude, and
direction of the energy) divided by charge.
Which explains George Ohm's law E=I*R. Claiming there is 'three' is just
comical.

Ask your buddy about Van De Graaf Generators and how ohm's three laws apply.
:)
That should be even more comical.
 
W

William Hayes

Jan 1, 1970
0
Frank Bemelman said:
Let's go all nuts and talk about ohmistance & ohmistors from now on ;)

Cripes, You want these guys/gals to actually learn something ??
 
R

Ratch

Jan 1, 1970
0
Mark Jones said:
I think, for "practical" electronics, the "ohmic" and "non-ohmic"
properties of resitance and its implication in the Ohm's Law equation is
largely depreciated. All resistors are likely assumed ohmic except for
specialty devices or applications, most of which deal with temperature and
not voltage. Personally, I find the voltage-dependant-negative-coefficient
resistances (such as carbon fiber) particularly interesting. :)
As I pointed out earlier, there is no "Ohm's law equation". I believe
you are referring to the resistance formula R=V/I and its variations, which
is not Ohm's law, although it is often mistakenly called that. Ohm's law is
a property of a material as explained in
http://www.launc.tased.edu.au/online/sciences/PhysSci/done/electric/resistnc/Resistance.htm
which I posted earlier. Did you read it? Ratch
 
W

Watson A.Name - 'Watt Sun'

Jan 1, 1970
0
[snip]
This proportional changes was used by Hewlett and Packard when they invented
their popular 202 oscillator. And another common non-ohmic device is a LED.

I believe the 202 wasn't their first osc. I used a HP 200CD audio osc
back in the '60s when I worked for a radio eng'g lab and it wasn't the
earliest.
That is why almost every LED requires a series resistor to limit its current.
At a given voltage, it will lower its resistance and go into thermal runaway,

Whoops! You should not have said "lower its resistance". You should
have said, it will lower its voltage drop. After all, it's not an
ohmic device.
destroying itself. As for the small LED flashlights with the button cells, the
batteries themselves provide an intrinsic resistance that limits the current,
and so they often have no resistors.
You will find that semiconductor junctions in general are all non-ohmic
devices, along with lamps and Nernst glowers. So are gas discharge tubes, etc.

This is the first I've heard of the Nernst glower - never heard of it
before. I did a google search and found this site, which tells a lot
about this German guy. I remember that when I was in Germany, a lot
of stuff had AEG on it.

http://www.nernst.de/

Tell me. Do you believe in negative resistance? :)
Cheers!

Chip Shults
My robotics, space and CGI web page - http://home.cfl.rr.com/aichip

--
@@F@r@o@m@@O@r@a@n@g@e@@C@o@u@n@t@y@,@@C@a@l@,@@w@h@e@r@e@@
###Got a Question about ELECTRONICS? Check HERE First:###
http://users.pandora.be/educypedia/electronics/databank.htm
My email address is whitelisted. *All* email sent to it
goes directly to the trash unless you add NOSPAM in the
Subject: line with other stuff. alondra101 <at> hotmail.com
Don't be ripped off by the big book dealers. Go to the URL
that will give you a choice and save you money(up to half).
http://www.everybookstore.com You'll be glad you did!
Just when you thought you had all this figured out, the gov't
changed it: http://physics.nist.gov/cuu/Units/binary.html
@@t@h@e@@a@f@f@l@u@e@n@t@@m@e@e@t@@t@h@e@@E@f@f@l@u@e@n@t@@
 
R

Ratch

Jan 1, 1970
0
Chuck Harris said:
Hi Ratch,

It is not as simple as all that. E = Ri has been called "Ohm's" law for
as far back as my reference library goes, which is 1907. I cannot
verify, but I would presume that the origin of the the alleged misuse
goes even further back.

The publication that gets it wrong first should not be the one to
follow.
In any case, this relation has been called Ohm's law for so long, that
regardless of its origin, it *is* Ohm's law. To try and change the
common usage at this late date would just needlessly confuse the issue.

Calling R=V/I the resistance formula does not seem confusing. What are
you going to call the resistive linearity property of a material as
explained in
http://www.launc.tased.edu.au/online/sciences/PhysSci/done/electric/resistnc/Resistance.htm
if you insist on hijacking its name for something else?

By the way, I can quote a couple of snippets from two good physics books
that back up what the above site contends.
 
Top