Marriage is under fire!!

[Tim Auton]

Chris Holmes <seymour_bunzzERASE@hotmail.com> wrote:

Tim Auton wrote:
maxel@berkeley.edu (Michael) wrote:

I am performing a test to measure the impedance through electrode pads
placed on opposite parts of the human body. The protocol requires that
the measurement be made by maintaining an AC sine current of 200mArms,
sweeping the frequencies from 200kHz to 5MHz [...]

If you want to stop someone's heart it's much easier to stab or shoot
them.

Maybe this circuit is for a cadaver lab. ;-)

In the Burke and Hare sense?


Tim
--
Guns Don’t Kill People, Rappers Do.

 

[Watson A.Name - \"Watt Su]

"eYeLess" <eye1ess@hotmail.com> wrote in message
news:9fa8f5bc.0409211820.6849310e@posting.google.com...

hi what do u guys recommend for home lightning control to use: solid
state relays, TRIAC, high power mosfet, igbt, thyristor????
thanks

Use a kite with a tinsel string and a key at the end. ;-)

 

[Fred Bartoli]

"Jamie" <jamie_5_not_valid_after_5_Please@charter.net> a écrit dans le
message de news:10l5t6ri3ui6d7a@corp.supernews.com...

Hmm
last time i knew that much current passing through the body could cause
some fatel damage.
are you sure it isn't 200 Na ?

Na, it should be 200 fA, but not 200 fucking Amperes...


--
Thanks,
Fred.

 

[Jamie]

Hmm
last time i knew that much current passing through the body could cause
some fatel damage.
are you sure it isn't 200 Na ?


Michael wrote:

I am performing a test to measure the impedance through electrode pads
placed on opposite parts of the human body. The protocol requires that
the measurement be made by maintaining an AC sine current of 200mArms,
sweeping the frequencies from 200kHz to 5MHz, and measuring the Vrms
between one electrode and a reference point on the body. The impedance
is to be calculated by dividing this voltage by the known 200mArms
current.

How do I sweep frequencies while maintaining a constant 200mArms
current using a HP 33120A (waveform generator w/ 0-15MHz freq and
0-10V peak to peak) or a HP 4192A (impedance analyzer w/ 0-15MHz freq
and -1V-+1V peak to peak)? Can I construct a circuit external to one
of these units and accomplish the 200mArms sweep? If not, what
lowest-cost set-up could?

 

[Chaos Master]

w_tom writes within:

Best to use 'zero crossing' triacs. This will minimize
power dissipated in that triac.

Exactly, I forgot this. This is what replying when you're tired gives.

--
Chaos MasterŽ, posting from Brazil.
"Two of the most famous products of Berkeley are LSD and Unix. I don't think
that this is a coincidence." -- Anonymous
"I'd rather be hated for who I am, than loved for who I am not" - Kurt Cobain

The Evanescen(t/ce) HP: http://marreka.no-ip.com

 

[CFoley1064]

Subject: How does a time registration with photofinish exactly works?
From: ilse.backers@student.khbo.be (Ilse Backers)
Date: 9/23/04 12:32 PM Central Daylight Time
Message-id: <b131f63a.0409230932.4b4099a8@posting.google.com

Hello,

Can somebody tell me more about how does a time registration with
photofinish (e.g. in a cycling race, in a speedskating race,...)
exactly work?
What is the accuracy of it? And what do you have to do if you want it
as accurate as possible? Are there other influences on it???
Can somebody tell me also how it, electronically seen, works?

Thank you!!

A good block diagram of a modern race timing system is shown on this website

http://www.splitsecond.com.au/greyhound.htm

Timings to the nearest millisecond are typically obtainable with this method.

Longer distance LED photosensors are typically modulated at an intermediate
frequency for better receptivity. Faster response times can be obtained by
increasing the modulating frequency of the LED emitter and phototransistor
receptor bandpass filter, making response times less than 1 ms. Photosensor
manufacturers catalogs have all kinds of information on this method.

http://www.bannerengineering.com/literature_resources/tutorial/old/1_sensi
ng_intro.html

While accuracy better than 1 ms really isn't necessary (and the backup of a
camera, typically CCD, provides a photo record in case of a "tie", anyway), you
can improve on this by dropping the modulating frequency and just going off
dramatic changes in photosensor output, which decreases your sensitivity to
electrical noise. Another possible here is using a low power laser diode, and
providing a point-to-point aim for sensing. The limiting factor then becomes
phototransistor response times. These can be improved again by using a
photodiode and amplifier. But at this point, we're way beyond any reasonable
accuracy for race times (better than than 10 microsecond, or .01 millisecond
resolution).

I hope this has been of help.

Chris

 

[Kevin Aylward]

John Popelish wrote:

anonymous wrote:

I get the naming difference - what are the different uses for each?
IE why would one use one vs another?

Fet is field effect transistor, the generic name for a gain device
based on the electrostatic modulation of conductivity in the channel
between source and drain.

JFET is a junction fet. The isolation between gate and channel is a
reverse biased PN junction. These are depletion only devices
(normally on, turned off by gate bias voltage).

Usually, but not only. There are a few exceptions

Kevin Aylward
salesEXTRACT@anasoft.co.uk
http://www.anasoft.co.uk
SuperSpice, a very affordable Mixed-Mode
Windows Simulator with Schematic Capture,
Waveform Display, FFT's and Filter Design.

 

[Clarence]

"Cali" <caliberelectro@home.in.th> wrote in message
news:47ad3616.0409251745.61742984@posting.google.com...

Objective: The purpose of the Electronic Design Contest is to promote
excellence in the design of electronic systems and help the company to
improve circuit design quality by providing competition between
graduate and undergraduate students at universities and colleges.

Award: The 1st winner will be grant $100, and the 2nd winner will
be grant 10% discount coupon.

Problem: Design DC. motor speed control circuit that is used to
control the speed of direct current. Click here for more information
(Please don't copy the design from a link.)

Criteria: Submissions are made electronically via the
TechnologyKit.us web site. Electronic Design Diagram must be drawn in
Microsoft Visio file format. The deadline for submission is October
30, 2004

To submit your data, please go to www.TechnologyKit.us

Didn't we see this a while back?

I notice the prices are rather high. They list a DC motor controller in their
product list, and a NiCad battery charger kit for $12.99. You can buy a
charger for ac or dc in that charges four cells for abt $14 and they include
the cells.

 

[Clarence]

"Clarence" <no@No.com> wrote in message
news:xOu5d.1638$JG2.631@newssvr14.news.prodigy.com...

"Cali" <caliberelectro@home.in.th> wrote in message
news:47ad3616.0409251745.61742984@posting.google.com...
Objective: The purpose of the Electronic Design Contest is to promote
excellence in the design of electronic systems and help the company to
improve circuit design quality by providing competition between
graduate and undergraduate students at universities and colleges.

Award: The 1st winner will be grant $100, and the 2nd winner will
be grant 10% discount coupon.

Problem: Design DC. motor speed control circuit that is used to
control the speed of direct current. Click here for more information
(Please don't copy the design from a link.)

Criteria: Submissions are made electronically via the
TechnologyKit.us web site. Electronic Design Diagram must be drawn in
Microsoft Visio file format. The deadline for submission is October
30, 2004

To submit your data, please go to www.TechnologyKit.us


Didn't we see this a while back?

I notice the prices are rather high. They list a DC motor controller in
their
product list, and a NiCad battery charger kit for $12.99. You can buy a
charger for ac or dc in that charges four cells for abt $14 and they include
the cells.

Correction, Sunday paper add, charger and 4 cells for $9.95

 

[Clarence]

"Cali" <caliberelectro@home.in.th> wrote in message
news:47ad3616.0409251746.7648cb8@posting.google.com...

Objective: The purpose of the Electronic Design Contest is to promote
excellence in the design of electronic systems and help the company to
improve circuit design quality by providing competition between
graduate and undergraduate students at universities and colleges.

Award: The 1st winner will be grant $100, and the 2nd winner will
be grant 10% discount coupon.

Problem: Design DC. motor speed control circuit that is used to
control the speed of direct current. Click here for more information
(Please don't copy the design from a link.)

Criteria: Submissions are made electronically via the
TechnologyKit.us web site. Electronic Design Diagram must be drawn in
Microsoft Visio file format. The deadline for submission is October
30, 2004

To submit your data, please go to www.TechnologyKit.us

"used to control the speed of direct current."

How fast do you want "DC" to go? What range of adjustment is needed.

Who owns the IP contained in the submittal?

Also, what is wrong with the Motor speed controller you advertise?

 

[Clint Sharp]

In message <13667c89.0409242352.849bb0f@posting.google.com>, Larry
<gemlover@tampabay.rr.com> writes
Generally, about seven pints of beer helps me detect elves.... YMMV of
course.


Seriously though, you might want to check out some of the paranormal
websites, they seem to do a natty line in various types of meter to
detect 'phenomena' which, IIRC, include ELF fields of the magnetic and
electrical sorts.
--
Clint Sharp

 

[Dan Stephen]

He's from Barthelona

 

[Gene the Skeptic]

A great way to get hold and choose from many circuits, without spending a
penny for an electronic engineer. $100 price?!?! A plumber in my
neighboorhood charges $100/hour!
Get real!
Gene the Skeptic


"Cali" <caliberelectro@home.in.th> wrote in message
news:47ad3616.0409251745.61742984@posting.google.com...

Objective: The purpose of the Electronic Design Contest is to promote
excellence in the design of electronic systems and help the company to
improve circuit design quality by providing competition between
graduate and undergraduate students at universities and colleges.

Award: The 1st winner will be grant $100, and the 2nd winner will
be grant 10% discount coupon.

Problem: Design DC. motor speed control circuit that is used to
control the speed of direct current. Click here for more information
(Please don't copy the design from a link.)

Criteria: Submissions are made electronically via the
TechnologyKit.us web site. Electronic Design Diagram must be drawn in
Microsoft Visio file format. The deadline for submission is October
30, 2004

To submit your data, please go to www.TechnologyKit.us

 

[John Fields]

On Sun, 26 Sep 2004 13:19:26 GMT, Hal Leemux
<Hal_leemuxNOSPAMMMPLEASE@yahoo.co.uk> wrote:

John Fields wrote:

Is it the kind of vibration sensor which gives you a lot of outputs
when it's being vibrated past its threshold, like this:

| |||| |
VIB __||__|||_|__||____|_||||____|_______


OUT____________________|_||||____|_______


or does it just give you one output, like this:

| |||| |
VIB __||__|||_|__||____|_||||____|_______

_____ _
OUT____________________| |___| |_____


If it only gives you one output, how long does the output stay hot
after the vibration goes away?


The sensor on its own gives lots of outputs as per your first example.
When in the latch schematic I mentioned in my original post it is
debounced slightly so it acts more like your second example.

The ultimate idea is to have a circuit which toggles on or off when the
sensor picks up a double knock in quick succession on a surface (exactly
like a double knock on a door).

---
OK. I just posted a basic circuit for you on
alt.binaries.schematics.electronic under the same subject as this
post.

If you need a circuit description or you need help with the timing
components and you know how much time you want between knocks and sets
of knocks post back (either here or to abse) and I'll help you figure
it out.

--
John Fields

 

[John Fields]

On 26 Sep 2004 06:44:40 -0700, smpaladin@yahoo.com (smpaladin) wrote:

http://www.geocities.com/smpaladin/circuit1.gif

This is what the above circuit is supposed to accomplish: As long as
a magnet is held above the hall sensor, it will turn on the coil. It
does that by utilizing a power transistor.

Will this setup work properly? Will it work properly if up to ten of
these circuits are connected to eachother and how much battery power
would I need to run it?

---
I won't run properly unless you connect the coil between the collector
of the transistor and battery + and connect a diode across the coil
with the cathode of the diode going to battery + and connect the
emitter of the transistor to battery -. It also won't work properly
if you don't have enough current coming out of the Hall sensor, and
you may toast the transistor if you don't put a resistor between the
output of the Hall sensor and the base of the transistor.

As for the rest of it, until you can more clearly describe what the
parts look like, electrically, and what you really want to do, you're
just pissing in the wind.

--
John Fields

 

[John Woodgate]

I read in sci.electronics.design that Wayne <nospam-mail@wlawson.com>
wrote (in <swE5d.672$Ue2.441@newsfe6-gui.ntli.net&gt about 'Finding the
Capacitance from Lissajour plot info?', on Sun, 26 Sep 2004:

The resistor is in series with the capacitor and the signal gen is
across one lead of the capacitor and one lead of the resistor. In other
word, if they were both resistors it would be a voltage divider. The
resistor or the capacitor can be ground. Forgive me for asking a dumb
question but why are V_c^2 + V_r^2 = V_s^2 to the power of 2?

Because the two voltages have a phase difference of 90 degrees (or, in
practice, very nearly; the capacitor won't be perfectly loss-free).

If this
was a voltage divider then you would have V?=Vs(R/R+Rc)?

In method 2 could you give me an example with the following figures?

Vs=10v p-p
Vr=4v p-p
Phase = 45deg (with respect Vs)

It's helpful to use a 'phasor diagram' to see what is going on. The
current I is in phase with the voltage across the resistor, and the
voltage across the capacitor is at 90 degrees to the current. So our
diagram is (*use Courier font*):

/|
/ |
/ |
/ |
Vs = 10 / |
/ | Vc =?
/ |
/ |
/ |
/ 45 |
/__________| ----------> Current I
Vr = 4 V

Now, I hope you can see that this is not, in theory, possible. The angle
at the apex of the triangle must be 45 degrees as well and the triangle
must be isosceles. So Vc must be 4 V as well, and then by Pythagoras
(which is the same as the squared values in Tim's equation), Vs =
sqrt(4^2 + 4^2) = sqrt(32) = 5.66 V.

One practical explanation, if your figures are correct, is that the
capacitor is very lossy, thus having a lot of resistance of its own.
This add to the horizontal side of the triangle (without altering the 4
V across the resistor). Another 3.07 V brings the figure right. The Vc
must also be 7.02 V, of course, because of the 45 degrees. We then get
by Pythagoras, Vs = sqrt(7.07^2 + 7.07^2) = sqrt(100) = 10.

It's a very poor capacitor if this is true. There are other
possibilities. What frequency are you working at and what are the
resistor and capacitor values? Have you actually measured 10 V at the
signal generator, or is that just what the output control says? If the
signal generator source impedance isn't very much smaller than the
impedance of your RC circuit, the Vs value will be way off, indeed it
may well be 5.66 V!
--
Regards, John Woodgate, OOO - Own Opinions Only.
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

 

[Rich Grise]

On Sunday 26 September 2004 01:44 am, Clarence did deign to grace us with
the following:

Also, what is wrong with the Motor speed controller you advertise?

The guy's probably pulling his design because they won't pay royalties.

Cheers!
Rich

 

[Michael Black]

Rakesh Sharma (srakesh@hotmail.com) writes:

Hi,

How would I construct an XOR function using NOR gates ONLY? I have
tried breaking my head over it but haven't come up with a solution.

Thanks in advance

Rakesh

I've deliberately taken out the cross-posting.

You do realize that this sort of question is in all kinds of books. If
you don't have a source to look it up, you do lack a basic library that
everyone interested in electronics should have.

One could go to the public library if one's stuck for lack of books.

Likely a search of websites will turn it up.

Finally, the only real reason you would want to do this is for homework.
It's much simpler to get an exclusive-or gate than wire up other gates.
Michael

 

[CFoley1064]

Subject: Will this circuit work?
From: smpaladin@yahoo.com (smpaladin)
Date: 9/26/2004 8:44 AM Central Daylight Time
Message-id: <6753235c.0409260544.6bb30078@posting.google.com

http://www.geocities.com/smpaladin/circuit1.gif

This is what the above circuit is supposed to accomplish: As long as
a magnet is held above the hall sensor, it will turn on the coil. It
does that by utilizing a power transistor.

Will this setup work properly? Will it work properly if up to ten of
these circuits are connected to eachother and how much battery power
would I need to run it?

Hi, Paladin. There are many types of Hall Effect sensors, and you're not too
specific about which one you're using, so I can't say for sure. However...

Many hall effect sensors are made with "open collector" output. That means
that, when they're on, their output pin will sink a few mA of current from a
pullup resistor or other source.

If you've got a type like that, you might want to try using a PNP transistor
and try something like this (view in fixed font or M$ Notepad):

.----------o--------------o----.
| | | |
| | | |
| | | |
| | .-. |
| .----o---. R| | |
| | + | | | |
| | | '-' |
| | Hall | ___ | |<
| | Effect o----|___|-o--|
--- | Sensor | R |\
- | | |
| | | .---o
| | - | | |
| '----o---' | |
| | | C|
| | - C|
| | ^ C|
| | | |
'----------o---------------o---'
created by Andy´s ASCII-Circuit v1.24.140803 Beta www.tech-chat.de

Choose R such that about 1/10th of the current required by the relay coil will
be drawn by the base (note that many of these hall effect sensors are limited
to about -20 mA output current, so keep that in mind).

I hope this works for you. Be sure to check your sensor to check the specs.
If you're not sure, feel free to post again with more information. Battery
voltage, relay coil resistance, sensor type would all be helpful.

Good luck
Chris

 

[Andyb]

"Michael Black" <et472@FreeNet.Carleton.CA> wrote in message
news:cj7jg4$6he$1@freenet9.carleton.ca...

Finally, the only real reason you would want to do this is for homework.
It's much simpler to get an exclusive-or gate than wire up other gates.

Why's everyone got such a downer on helping kids with homework? Sure, don't
do it for them, but a prod in the right direction is reasonable.

In my day <dons slippers><lights pipe> we'd have got extra marks for knowing
where to look for help on the Internet!

Andyb
--
The above email address is whitelisted.
If I don't have your address already, I wont see your message.