Marriage is under fire!!

[Rich Grise]

Brett Cummins wrote:

Hi,
Get your hands on a Voltmeter, or ask your dad for one. Then find out
if
your battery gives out still 12 V or more. You do this by connecting one
of de negative leads with the com of the meter and the positive with the
positive from the meter do this for all 4 combinations (naturaly) ... By
this time you will have found out if you need to use all four leads from
the battry or not..... and if the battery is any good .


Hey!
Thank's for the response! I actually have a voltmeter, because
I'm into model railroading. I wired it like you said and set the
meter's dial to 20 DC volts. I get a reading of about 2.80. For a 12
volt battery, I'm assuming that it should read 12. Is the battery
almost dead, or am I reading this wrong? Thanks again!

You could have potentially up to 6 readings. Label the leads, say,
A, B, C, and D. You can put the meter across AB, AC, AD, BC, BD, or CD,
and will have to observe polarity while doing it.

ixTell us those se readings, and it will tell us a lot more about
the battery.

Cheers!
Rich

 

[Geir Klemetsen]

"Bill Christens-Barry" <equipoise1@verizon.net> skrev i melding
news:equipoise1-3A4DEB.18581019082004@news.verizon.net...

I have a circuit board with a capacitor that needs replacing (it got
burned when an adjacent triac went out). The capacitor is a small "bead"
shape, and has the code:

1C4
ME5

printed on it.

I can't find anything on the web about this particular code format - can
anyone help me figure out what its value and max voltage is?

The circuit has another one of these capacitors, and I thought about
pulling it and trying to test its value. My idea is to charge it up to a
known voltage, and time how long it takes to discharge through a known
resistor. My problem is that I don't know what the impedance of the DVM
voltmeter is, and this will influence the discharge rate due to its
parallel resistance. Any ideas on how to approach this? I guess I could
do this experiment twice, using two different known resistor, and back
out the meter resistance. Any better ideas? I don't have easy access to
any good electronics bench equipment, so am looking for simple approach.

BTW, I could post a digital closeup photo of the capacitor if that would
help.

Thanks.

Bill Christens-Barry

--
Wm A Christens-Barry, PhD
Equipoise Imaging, LLC
equipoise1@verizon.net
http://www.eqpi.net/eqpi/

Best sugestion:
Go buy a capacitance meter.

Second best suggestion:
Build an oscillator that make use of _one_ capacitor. It's important that
you are able to calculate the oscillation frequens for that particular
oscillator. You have an formula f = (r, c). Turn this into
c = (f, r).
Example: http://www.national.com/an/AN/AN-31.pdf page 8. The formula should
be like this:
T = 2 * R1 * C1 * ln( 1 + ( 2*R2/R3 ) ) ( T = 1/f )
Turning the formula to calculate C:
C1 = T / ( 2 * R1 * ln( 1 + ( 2*R2/R3 ) ) )

Hope this helps : )


Geir

Btw: This is second time i post this message. It doesn't show up in the
news-group after the first time I posted it.

 

[Peter Bennett]

On 22 Aug 2004 16:39:23 -0700, packerfan6000@yahoo.com (Brett Cummins)
wrote:

Hey!
I'm 14 and I'm trying to power a small neon light that requires a
12 volts of electricity (usually for a car)with a 12 volt battery . I
have an old rechargable battery from a toy car that I had when I was
little. I removed the battery, and I realized that there is a four pin
connecter with four wires leading from it. There are only two wires
going to the neon tube, so how do I do this? Do I only need to use two
of the wires, or do I need to connect the two positive wires together
and the two negative wires to form the two necessary connections?
Thank you!

I expect that a rechargeable battery 8 - 10 years old will be useless
after all these years. It will certainly be almost fully discharged
by now, and probably won't hold a charge if you try to recharge it.




--
Peter Bennett, VE7CEI
peterbb4 (at) interchange.ubc.ca
new newsgroup users info : http://vancouver-webpages.com/nnq
GPS and NMEA info: http://vancouver-webpages.com/peter
Vancouver Power Squadron: http://vancouver.powersquadron.ca

 

[Fritz Oppliger]

On Tue, 24 Aug 2004 18:47:00 GMT, Andyb <andrew.blakeney@ntlworld.com>
wrote:

"Fritz Oppliger" <fritzo_two_@direcway.com> wrote in message
newspsc7jboefkwe1hx@free.teranews.com...
I want to regulate a peltier cooler. Manufacturer says they don't like
to
be switched on and off alot, they prefer changing input voltage.
On the controller I have available a DAC output 0...2.5 VDC .
What is the most elegant way to turn this into 0...14VDC at 6 amps max?

I built something to control one of these things a while back. The
manufacturer said that it is okay to use pulse width modulation at
frequencies above 1kHz, so that's what I did and it worked fine! If you
don't get any joy with an analogue solution, you could think along the
lines
of 555 - H-Bridge.

Good luck!

Thanks-

One of my dilemmas is that I have run out of digital output lines but have
these DACs sitting idle.
So I'll try that first.

 

[BretCahill]

Someone suggested a 2-stroke/4-stroke
convertable engine. 4-stroke if gas was
expensive and four stroke if you needed more
power.

The sliding cam was the only way other than
solenoids.


Bret Cahill

 

[Rheilly Phoull]

"peter" <peter_chans@hotmail.com> wrote in message
news:bf5dca45.0408242207.249b58e7@posting.google.com...

Hello all
Just have a techniacl question. Over the passed 2 days I'm trying to
think of a way to build a power suppyly for may magellan sportrak
map(gps) which needs 3.8vdc-4.2vdc that will be converted from cars
12vdc. What is the best way to put that power supply togther ueseing
easy to find.
Thanks in adcance.

Look up the LM317, that is an adjustable voltage regulator just made for YOU
. Very simple circuit to do what you want, with a bit of ingenuity it
should be able to fit it inside a generous cigarette holder plug.


--
Regards ........... Rheilly Phoull

 

[CFoley1064]

Subject: Re: stepdown dc/dc power
From: "Rheilly Phoull" Rheilly@bigpong.com
Date: 8/25/2004 3:47 AM Central Daylight Time
Message-id: <2p321uFgf4srU1@uni-berlin.de


Look up the LM317, that is an adjustable voltage regulator just made for YOU
. Very simple circuit to do what you want, with a bit of ingenuity it
should be able to fit it inside a generous cigarette holder plug.


--
Regards ........... Rheilly Phoull

____
+ IN| |OUT +
o----o----| 317|----o------o------o LM317T (Front View)
| |____| | | .---------.
| ADJ| .-. | | |
| | 240| | | | o |
.1uF|+ | | | 1uF|+ | |
--- | '-' --- |---------|
--- | | --- | |
12V | o-------' | 4.2V | |
| | | | |
| .-. | | |
| | | | '---------'
| | |560 | | | |
| '-' | | | |
- | | | - | | |
o----o------o--------------o------o A O I
D U N
J T
created by Andy´s ASCII-Circuit v1.24.140803 Beta www.tech-chat.de

Good luck
Chris

 

[John Larkin]

On 25 Aug 2004 08:48:13 -0700, hbonwit04@yahoo.com (Holden Bonwit)
wrote:

I was curious if anyone knew of a vendor who makes/sells high voltage
LEDs. I have a 25 volt power supply, and for various reasons don't
want to step down the voltage to ~12 volts with a voltage regulator.

If it helps, or makes a difference, I'm looking for an IR led with a
wavelength of about 830 nanometers, but would like to hear of any
suggestions that people have for LED vendors.

Thanks,

Holden
hbonwit04 at yahooDOTcom

All IR led's have about the same inherent voltage drop, 1.2 volts or
so. Just add a series resistor.

John

 

[w_tom]

www.LEDtronics.com We had been using a 24 VAC version for 15
years now.

Holden Bonwit wrote:

I was curious if anyone knew of a vendor who makes/sells high voltage
LEDs. I have a 25 volt power supply, and for various reasons don't
want to step down the voltage to ~12 volts with a voltage regulator.

If it helps, or makes a difference, I'm looking for an IR led with a
wavelength of about 830 nanometers, but would like to hear of any
suggestions that people have for LED vendors.

 

[Clint Sharp]

In message <545d8ce4.0408241554.21009c10@posting.google.com>, James
Newton <jamesnewton@geocities.com> writes

bretcahill@aol.com (BretCahill) wrote in message
news:<20040822132501.14634.00002073@mb-m29.aol.com>...
Could a solenoid be constructed to mimic
the proper valve position vs time curve of a
engine cam shaft?

Anything is possible, but if you just want variable valve timing try
this:
Snip,

Fiat use a scheme like this. Their system uses two meshing cross cut
gears, one internal and the external one is rotated to push/pull the
camshaft in and out to a different portion of the profile
--
Clint Sharp

 

[Roger Hamlett]

"Holden Bonwit" <hbonwit04@yahoo.com> wrote in message
news:a3a89300.0408250748.cdf8476@posting.google.com...

I was curious if anyone knew of a vendor who makes/sells high voltage
LEDs. I have a 25 volt power supply, and for various reasons don't
want to step down the voltage to ~12 volts with a voltage regulator.

If it helps, or makes a difference, I'm looking for an IR led with a
wavelength of about 830 nanometers, but would like to hear of any
suggestions that people have for LED vendors.

Thanks,
Seriously, even if such a high voltage LED existed, you would need to

current regulate, since the forward drop will change with temperature.
Ideally, you need to get an LED with drive electronics built in. 25v units
are quite common, since trucks use nominally 24v electronics, and many now
use LED rear lights, and instrument panel lights like this. Many are made
by SLi http://www.sli-ml.com/led.htm, and Agilent, but these companies
rarely do IR LEDs, so it does make a large difference that this is the
frequency band needed.
You don't say what sort of brightness you require.
Remember also, that you can series connect several LED's, and minimise the
resistance that has to be used. So (for instance), you could series
connect perhaps 9 IR LEDs, and then have perhaps a 25R resistor to limit
the current (you would need to check the typical forward voltage at the
rated current, but normally this is about 2.4v, for the AIGaAs/GaAS
Technology normally used at this frequency). This would be for a 100mA
rated LED, like the QLD-830-100S.
Some of the LED manufacturers do offer small switch mode drive modules
that will cover this voltage range.

Best Wishes

 

[Tom Biasi]

"Richard" <beezoboar@hotmail.com> wrote in message
news:9fa77d4c.0408240515.24b0d7d3@posting.google.com...

Funny, I still have an "Allied Radio Corp" coil calculator (paper
slide rule) for dimensions so you can wind your own RF inductors.

From high school days, back when we had to walk 10 miles through chest
deep snow to get to school...

Up hill both ways?

 

[Rich Grise]

Tom Biasi wrote:

"Richard" <beezoboar@hotmail.com> wrote in message
news:9fa77d4c.0408240515.24b0d7d3@posting.google.com...

Funny, I still have an "Allied Radio Corp" coil calculator (paper
slide rule) for dimensions so you can wind your own RF inductors.


From high school days, back when we had to walk 10 miles through chest
deep snow to get to school...

Up hill both ways?

You had snow? We had to swim through the magma that was yet to become
crust...

 

[Rich Grise]

peter wrote:

Hello all
Just have a techniacl question. Over the passed 2 days I'm trying to
think of a way to build a power suppyly for may magellan sportrak
map(gps) which needs 3.8vdc-4.2vdc that will be converted from cars
12vdc. What is the best way to put that power supply togther ueseing
easy to find.
Thanks in adcance.

You don't say what country you're in, but RS has various car lighter
adapters with the regulator already in them, I'm pretty sure.

Good Luck!
Rich

 

[Michael A. Covington]

Quantum physics dictates that LED voltage is related to wavelength -- about
1.8 volts for red, 3.6 volts for blue, 4 volts for ultraviolet (the white
ones are ultraviolet plus a phosphor).

All LEDs require current-limiting resistors. There are no 12-volt LEDs
either; LED lamps that run on 12 volts have the resistors built in.


"Holden Bonwit" <hbonwit04@yahoo.com> wrote in message
news:a3a89300.0408250748.cdf8476@posting.google.com...

I was curious if anyone knew of a vendor who makes/sells high voltage
LEDs. I have a 25 volt power supply, and for various reasons don't
want to step down the voltage to ~12 volts with a voltage regulator.

If it helps, or makes a difference, I'm looking for an IR led with a
wavelength of about 830 nanometers, but would like to hear of any
suggestions that people have for LED vendors.

Thanks,

Holden
hbonwit04 at yahooDOTcom

 

[JeB]

On 24 Aug 2004 23:07:33 -0700, peter_chans@hotmail.com (peter) wrote:

Hello all
Just have a techniacl question. Over the passed 2 days I'm trying to
think of a way to build a power suppyly for may magellan sportrak
map(gps) which needs 3.8vdc-4.2vdc that will be converted from cars
12vdc. What is the best way to put that power supply togther ueseing
easy to find.
Thanks in adcance.

adaptors which provide up to 1 amp at a wide selection of voltages and
with an assortment of plug adaptors are very affordable.

 

[Paul Burridge]

On Wed, 25 Aug 2004 19:36:52 -0400, "Michael A. Covington"
<look@ai.uga.edu.for.address> wrote:

Quantum physics dictates that LED voltage is related to wavelength -- about
1.8 volts for red, 3.6 volts for blue, 4 volts for ultraviolet (the white
ones are ultraviolet plus a phosphor).

All LEDs require current-limiting resistors. There are no 12-volt LEDs
either; LED lamps that run on 12 volts have the resistors built in.

I got some ultrabright whites the other day. Not much info on 'em,
though. Typical values only given; no maximums. Vfwd was 3.4V; Ifwd
was 30mA. Can anyone hazard a guess as to what the *do not exceed*
figures might be? They tend to draw more current as they get hotter
and when bunched close together and they do generate quite a bit of
heat. I'm worried I might exceed the 30mA (typ.) figure by too much
and blow 'em.
--

"What is now proved was once only imagin'd." - William Blake, 1793.

 

[Ken Smith]

In article <412d238b$1@mustang.speedfactory.net>,
Michael A. Covington <look@ai.uga.edu.for.address> wrote:

Quantum physics dictates that LED voltage is related to wavelength -- about
1.8 volts for red, 3.6 volts for blue, 4 volts for ultraviolet (the white
ones are ultraviolet plus a phosphor).

At least some white ones are blue and a phosphor and have a drop of about
3.5V.

--
--
kensmith@rahul.net forging knowledge

 

[Paul Hovnanian P.E.]

"Michael A. Covington" wrote:

Quantum physics dictates that LED voltage is related to wavelength -- about
1.8 volts for red, 3.6 volts for blue, 4 volts for ultraviolet (the white
ones are ultraviolet plus a phosphor).

Maybe an X-ray LED will run at 24V. ;-)

All LEDs require current-limiting resistors. There are no 12-volt LEDs
either; LED lamps that run on 12 volts have the resistors built in.

Or a combination of series LEDs and a resistor, or (if efficiency is
critical) a switched mode regulator. I've seen some app notes for LED
drivers, but not having done any LED work recently, I can't lay my hands
on the part numbers as quickly as a good search engine might.

--
Paul Hovnanian mailtoaul@Hovnanian.com
note to spammers: a Washington State resident
------------------------------------------------------------------
Just say 'No' to Windows.
-- Department of Defenestration.

 

[w_tom]

Wow! So many responses saying LED is not possible. Any low
voltage incandescent indicator lamp - any voltage AC or DC -
is sold as an LED from www.ledtronics.com and from other
companies. They require the lamp number and whether power
will be AC or DC. That's it.

Many decades ago, an L1011 crashed into the Everglades when
the flight crew, so busy trying to determine if an indicator
bulb had gone out, accidentally disconnected the automatic
pilot. (It also resulted in the book Ghost of Flight 401).
As a result, indicator lamps on aircraft even way back then
were replaced with LEDs. Did they change the voltage? Of
course not. They simply changed incandescent indicator lamps
with LED equivalents. The technology is that old - decades
old.

Holden Bonwit wrote:

I was curious if anyone knew of a vendor who makes/sells high voltage
LEDs. I have a 25 volt power supply, and for various reasons don't
want to step down the voltage to ~12 volts with a voltage regulator.

If it helps, or makes a difference, I'm looking for an IR led with a
wavelength of about 830 nanometers, but would like to hear of any
suggestions that people have for LED vendors.