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Coil
Sci.Electronics.Basics is a worldwide Usenet news group that is used to discuss basic electronics questions.
We found 494 threads matching "coil"
You are looking at page 1 of 13.
The most relevant threads are listed first
Crystal Radio Questions
Joe - 2009-07-20 03:07:00
I'm winding a coil for a crystal radio. The original plan says to wind
the antenna coil on top of the tuning coil, whereas another version says
to wind the antenna coil *adjacent* to the tuning coil, separated by about
1/4 inch.
If I wind both versions of the antenna coil on the form, will on...
Coil wrapping ?
mowhoong - 2007-09-06 10:47:00
I had seen a coil wrapped in twin wire. If I design a coil with 1000
T, I use two wire together,
so it mean that I only wrapp 500 T, hence it save my time and
work.Dear members do you have any comment ? Thanks
Regards
...Re: small, battery powered stepper motor
BobG - 2007-05-07 13:02:00
One problem with stepper motors is that one coil is always on.... a
'trick' to reduce the holding current is stick an R in series with
each coil. Use 4 outputs... a pair for each coil... energize coils
like this to go one way... 01 01, 01 10, 10 10, 10 01, and back to 01
01.
...Re: Which way is better, zener or resistor
John Popelish - 2007-08-18 19:57:00
Allen Bong wrote:
> I have a 12V relay and I wanted to operate it with 18V supply. Could
> I use a 6V 1W zener to drop the extra 6V from the supply or is it
> better to use a 150 ohm 1/2W resistor. Which will generate more
> heat? The relay operates with 20mA current.
In most cases, th...555 timer help
Bob1001 - 2007-12-02 21:57:00
I am new to this newsgroup, I am typically a poster on rec. pyro or
metalworking, but I have been working on a new project. I am trying
to
make an ignition coil for my new turbing engine, and I am quite
terrible at reading electronic designs. I know that I will be needing
a 555 timer, and an ig...How to test the primary coil on a microwave oven transformer for a short.
trg-s338 - 2010-02-01 02:20:00
I'm building a spot welder using a modified microwave oven
transformer. The project calls for removing the secondary coil
windings. In doing so, I accidentally "bumped" the primary coil with
a hammer resulting in 2 or 3 wires in the primary coil becoming
slightly displaced by about 1/8 of an i...Re: Looking for simple and reliable voltage doubler 12->24v
JeffM - 2007-03-05 16:51:00
rkremser wrote:
> This will be used to drive two air solenoid valves for shifting and clutching.
The solenoid valves I have seen have 2 parts:
the valve body and the coil.
You select the coil according to the voltage source you have
available.
Is getting a coil of the proper voltage not an o...Coils
KBSoftware - 2007-08-11 19:31:00
I a bit new to electronics, about 1.
Now I'm learning about coils, and have a few questions.
I have some coils and I know their Henry rating, I've found a lot of
information on coils.
Now I'm wondering if I took a coil let's say a 55uH applied maybe 3v,
what would be the voltage resulting. ...Re: Wireless Non-Radiative Energy Transfer = scalar wave transmission
Benj - 2009-01-10 18:34:00
On Jan 10, 1:18 pm, Edward Green wrote:
> There are still a few people around this zoo^H^H^H group who know
> something about radio, but I guess they are just too bored to comment,
> even for a pleasant pseudoscience debunking fest.
Ok. "evanescent waves' means "waves that die out" ["v...Basic auto ignition electric Q
Paul Conners - 2009-10-19 00:00:00
Single coil, rotor & distributor cap system, 4 cylinder.
Is the coil housing grounded? I always thought the coil housing was the
return path for the secondary circuit / spark current. I know that the
primary circuit doesn't use ground in the coil: it is grounded through the
ignition points...Re: Diode across inputs to solenoid?
2009-07-20 21:40:00
When you put current through an inductor (like the coil in your
solenoid), it builds up a magnetic "charge"[*], much like a capacitor
stores electric charge. Thus, it resists change to *current* much
like a capacitor resists change to *voltage*.
So, you energize the coil by putting a curren...Problem with a motor starter- 3phase 480 Volts
Butter - 2009-06-23 16:14:00
We are moving a hoist from a location in Pe. to our Ar shop. It was
supposedly in working order and when we tried to wire it up it is
malfunctioning. When you press either the up or down buttons
sometimes
nothing occurs and sometimes the coil of the contactor will
momentarily pull the contacts ...Re: Looking for simple and reliable voltage doubler 12->24v
rickman - 2007-03-05 09:52:00
On Mar 3, 7:51 pm, "Homer J Simpson" wrote:
> "jasen" wrote in message
>
> news:escohr$fmt$1@jasen.is-a-geek.org...
>
> > > Then you need to use a transformer - preferably with push pull drive.
>
> > huh? a charge pump needs push-pull but no transformer.
> > and a boost conv...Re: Low resistance
Jasen Betts - 2008-11-15 05:08:00
On 2008-11-14, PW wrote:
> I need to measure the resistance of some motorcycle alternator coils
> They should be about 1.5ohm
> I have a cheap DVM, which is of little use at this value
> Is there a simple way to do this keeping in mind that I have Zero
> electoral knowledge.
> Thanks...sizing a freewheeling diode for a coil
Matt - 2007-06-01 23:28:00
I am controlling the coil of a relay using a switching transistor. To
protect the transistor I intend to use a freewheeling diode in parallel
with the coil. I'm not sure of the issues in specifying the diode.
My impulse is to simply use a 1N4007
http://www.fairchildsemi.com/pf/1N/1N4007.ht...12V relay surging
2007-05-19 02:24:00
One problem here hopefully I can get this to work..
I wired a an automotive relay to drive a 12VDC RV water pump.
from a power supply,
12V+ going to 30 and 87 output to pump.
split same 12V going to coil +
ground going to the pump directly
split same ground going to the pump and also the c...What to use to hold Coil Windings in Place?
Archimedes - 2008-03-26 21:55:00
Hi All
Can anyone suggest whats best to use to hold the windings of an Air
Coil with about 7 turns, about 12mm long - I know i can use
polystyrene cement but are there any other options like maybe candle
wax ?
Thanks
Shelton.
...meaning of impedance(about imaginary part)
kanica - 2008-02-27 07:34:00
When I measured impedance of the RF system, I discoved decreasing
imaginary part(minus value). but!! it is minus value(like -5 -10
-12...) and the real part of impednace was incresed accoding to the
increasing power(13.56MHz). finally we find decreasing the impednce
I have a few question
1....Vehicle detector
Roger Dewhurst - 2006-09-12 16:52:00
Would a multi turn coil, a metre or two in diameter, buried beneath the
surfce of a driveway, with the ends of the coil connected to the input pins
of a operational amplifier serve as a reliable vehicle detector?
R
...Re: How to optimize parameters for making a coil with high-Q?
Phil Allison - 2008-06-20 20:30:00
"Arthur Cretin "
> >
> > > I want to make a simple coil (inductor) with a Q value as high as
> possible.
> >
> >
> > ** Air cored or not ??
> >
> > You are one colossal ASS for not saying so straight off.
>
> Thanks for the compliment. Return to sender, and take a wild guess.
...Re: Switching AC w/ Logic Level
Jamie - 2007-05-31 20:03:00
jecottrell65@gmail.com wrote:
> I've found a few threads but nothing with exactly looking for what I'm
> looking for.
>
> I need to switch 24VAC (HVAC control) and 120VAC (2A and 10A) with a
> PIC. What is the best way to do this? Opto-Isolated TRIAC, SSR?
>
> Your suggestions on y...Re: Will the LM393 drive a small relay?
John Popelish - 2007-04-24 12:03:00
Bob wrote:
> I need to switch on a relay with the output of the LM393. The relay
> is a 5vdc unit from RadioShack. Does the LM393 have what it takes to
> trigger this relay? If not what should I put between the relay and
> the LM393 to permit the 'output' of the relay to properly 'close' ...Relay Coil Suppression, DC relays
amdx - 2008-05-22 10:40:00
A question often asked is about relay coil transient suppression. I ran
across this in my files. It has some good information.
http://relays.tycoelectronics.com/appnotes/app_pdfs/13c3311.pdf
Mike
...Re: Using a relay
John Popelish - 2007-04-24 11:33:00
Jan Nielsen wrote:
> I got a relay I cant figure out how to use, it as 5 connectors.
>
> Its a finder 36.11.9.005.0000 5V(dc) 10A 250V(ac), I dont have a
> datasheet for it.
>
> The legs are like this
> O_O 1_2
> OOO 345
>
> 1=NO (Normally open?)
> 2=NC (Normally closed?)...Re: Need help calculating resistor needs in an electromagnet circuit
Greg Neill - 2009-12-29 10:35:00
trayos wrote:
[snip]
> I wrapped 22 gauge wire around this area 50 times and
> connected the ends to the DC output on a Railpower 1370 transformer. It
> has 120V AC input, 15V DC output and 18VA total output.
18VA/15V = 1.2A
That would be your maximum continuous current draw ...Re: wire for high current inductor
George Herold - 2010-02-01 10:37:00
On Feb 1, 7:34=A0am, "Budiyanto" wrote:
> I'm designing a 1 mH inductor with max current of 30 A. Anybody can give =
me
> suggestion what kind of wire should be used? thanks
Do you care about the Q of the coil? And if so at what frequency? Or
is this just DC. (Oh, air coil or will the...buck boost
2008-09-03 16:57:00
http://en.wikipedia.org/wiki/Buck-boost_converter
Is there a reason why the switch is between the voltage source and the
coil?
What would happen if the switch were between the voltage coil and
ground (as it is in the Boost converter)?
Thanks,
Michael
...Replacing Thermal fuse
Jon Slaughter - 2008-09-29 11:02:00
I have a dishwasher who's heating coil stopped working. Looked at the bottom
and the hot wire was charred and broken away from something.... that
something was cylindrical and had another wire going to it.
I'm guessing it was a thermal switch that didn't do it's job cause it was
pretty char...Need a quick inductive ignition tester
Michael - 2009-10-28 00:45:00
To test a non-starting vehicle's distributor, I need an inductive
ignition tester to see if the central high voltage wire is getting
juice.
Can I whip one up with a simple coil of electromagnet wire (~50
turns), connect to a DMM and place the coil near the HV wire?
Thanks,
Michael
...Coil driving
Nuby - 2007-10-13 13:58:00
What's wrong with this picture?
TTL control lines with small current sinking capability (say 20ma)
need to activate electromagnetic coils (50VDC, 300ma). Each control
line gates an SCR which runs Vcc into a coil. The group of coils has
a common disable in the form of a big relay that cuts th...Re: Speaking of solenoids...
default - 2008-12-20 17:47:00
On 20 Dec 2008 17:07:58 GMT, steamer wrote:
> --Yep those are the ones! I'm looking for more of same but *still*
> don't know who the mfr or what the product name originally was. Anyone got a
> clue?
If you are/were looking for solenoids you might find some that could
be modified to mak...radio transmissions at the frequency of light
jjoensuu - 2007-01-16 21:39:00
Hi all,
just wanted to ask, what would be the problems that make it
difficult/impossible to build a radio that transmits at the frequency
of visible light (between 430 and 750 Tera Hz)?
I guess one of them is that it is not possible for a regular coil
(copperwire around an air core) could n...Re: Motionless Induction
Michael Robinson - 2010-03-22 14:29:00
"RalfM" wrote in message
news:ho72hm$mab$1@speranza.aioe.org...
> Hi,
> let's say there is a magnetic field of a _permanent magnet_,
> and a fixed/nonmovable induction coil is placed into field.
> Is it possible periodically to change (ie. "disturb") the intensity
> of the said magn...Re: coil winding sensor
Rich Grise - 2008-06-19 16:04:00
On Tue, 17 Jun 2008 11:43:51 -0700, lerameur wrote:
>
> I want to make a coil winding machine, I would like to implement a sensor
> so I can count the velocity of the wire I am coiling so I can accurately
> count the length of the wire, is there any type of sensors out there that
> can do...Re: How to build a simple LC oscillator
Jamie - 2008-12-15 19:24:00
Alexis Bezverkhyy wrote:
> Hello !
>
> I'm new to analog electronics (although I've been using uCs for a while)
> and I'm trying to build a really simple RC oscillator, a Hartley or a
> Colpitts one. All the schematics I've found on the web or in books are
> using complex and additionna...Re: Curiosity
2009-09-22 18:37:00
On Tue, 22 Sep 2009, Periproct wrote:
> Just curious here.
>
> I managed to break the tiny coaxial connector on my express card TV tuner.
> Decided to remove the connector from the PCB, cut the small coaxial plug off
> the supplied lead and solder it directly to PCB.
> Having got the c...What happened? Solenoid mystery.
Eric R Snow - 2007-03-20 22:50:00
I have a solenoid actuated air valve that only occasionally is
operated. It is meant to be operated with 24 volts DC. I plugged in a
wall wart power supply and the solenoid just chattered. Looking at the
wall wart I see it's a 12 volt DC unit. Duh. So I grabbed the proper
24 volt DC wall wart of...Re: Ideas for electromechanical resonance?
Tim Wescott - 2009-08-24 12:06:00
On Mon, 24 Aug 2009 10:13:22 -0400, default wrote:
> I'm wondering if anyone has done this and how:
>
> I want to resonate a high carbon steel bar at its fundamental frequency
> to produce an audio tone. The bar is 1/8" thick, 6-1/2" long and 1-1/2"
> wide and resonates at about 400 Hz...Re: relay switching speed
Sjouke Burry - 2008-08-22 14:14:00
lerameur wrote:
> hello,
>
> I am trying to figure out is there is any rating on the maximum
> switching speed on mechanical relays such as the R3-24AC or 50-094-0
> (or just any mechanical relay) I want to use dc current on these and
> switch them possibly 1000Hertz or possibly 10,000H...Tesla coil parts - where to salvage?
Kasterborus - 2008-02-13 14:11:00
Hi,
I'm trying to put together a Tesla coil following plans for a vacuum
tube based design.
I need to find the following parts, and wondered if these could be
salvaged from anywhere...
1 x 0.004 mfd 1000 volt polypropylene capacitor
1 x 0.003 mfd 3 kv mica capacitor
3 x 0.01 mfd 10 kv m...