Electromagnet Help! How to Make a Small but very Strong Electromagnet???

I need you help smart people of Instructables!
I need to make a small Electromagnet, that uses minimum power (by that I mean the battery), but still has to be very powerful. I have a couple of questions that I need you to help me answer:
  • Does the number of coils that is wound to the metal bar effect the strenght of the electromagnet?
  • Does the wire gauge (20,24,28,30,34,36 wire gauge) make a difference is the strenght of the magnet?
  • Does the voltage I supply to the coil effect the Electromagnet?
  • What type of battery is best for an Electromagnet (AA, AAA, C, D), and what voltage (1,5V, 3V, 4,5V, 6V, 9V) ???

Here is the thing, I need to make the Electromagnet super strong but taking up the minimum of energy, for example, just 1,5V. The things that are not important to me (doesn't play a factor in my device) is the number of wire winds to the metal rod and the wire gauge!

So is it better to just make 1 or more (3,4,5,6...) layers of wire winds???
Is it better to use thinner (36 gauge) or thicker wire (24 gauge)???

Thank you a lot!

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RonM231 year ago

I am interested in elector-magnets using a closed loop containing mercury warped with copper wire to induce a magnetic field within. By my research the mercury should spin as per the multiple coils (DC current) within this circular tube. I postulize that this would constitute an electric generator in reverse of the norm, That is the stationary elector-magnets in the common generator will move in the form of the mercury going around in the tract. The spinning wire which is rotating rapidly on the normal generator will be stationary on mine. These are the coils warping the tube containing the mercury. So I have been in my head trying to see magnetic fields and propose a question to the ether's, what does my 2 ring, 16 rare earth magnets magnetic field look like in 2 dimension


mag 03.jpg
nerked RonM234 months ago

Self-taught British scientist Michael Faraday (1791 – 1867) was the
first to understand what these discoveries implied. If a magnetic pole
could be isolated, it ought to move constantly in a circle around a
current-carrying wire.

In 1821 Faraday set about trying to understand the work of Ørsted and
Ampère, devising his own experiment using a small mercury bath. This
device, which transformed electrical energy into mechanical energy, was
the first electric motor.

This apparatus is the only original surviving example made by Faraday the following year after his discovery in 1822.

The motor features a stiff wire which hang down into a glass vessel
which has a bar magnet secured at the bottom. The glass vessel would
then be part filled with mercury (a metal that is liquid at room
temperature and an excellent conductor). Faraday connected his apparatus
to a battery, which sent electricity through the wire creating a
magnetic field around it. This field interacted with the field around
the magnet and caused the wire to rotate clockwise.

This discovery led Faraday to contemplate the nature of electricity.
Unlike his contemporaries, he was not convinced that electricity was a
material fluid that flowed through wires like water through a pipe.
Instead, he thought of it as a vibration or force that was somehow
transmitted as the result of tensions created in the conductor.

nerked nerked4 months ago

That's the motor, and this other picture is a mercury bridge rectifier have you ever seen one of these?! If not i highly recommend that.

nerked nerked4 months ago

Mercury arc rectifier.... lol

ChuckF21 RonM2310 months ago

Laboring purposefully and diligently towards directing powerful forces. Forces that are bounded by, and determined by, laws of nature; whereby execute a set coarse of actions yet, of these actions, we've only the understanding and awareness of a portion of the entirety. Laws of attraction are so often quietly joining like components together, though not as often likely to receive the credit for these actions.

Sorry, I must confess that I don't have any information for your project, though I was compelled to reply due to a persistent, yet vague, desire to experiment with mercury, magnetism, and electricity. It has become a distraction that disrupts my concentration on any given task. When that occurs I find myself conducting experiments in my head with the hopes of visualizing changes and results. Hence, I'd be very interested in obtaining updates and information or videos in relation to your project. I wish you luck and success, always imagine and expriment.

jinumohan3345 months ago
What auage wire is used in solenoid 12 volt DC input for more power
TaimoorK56 months ago

which gauge of wire is best for strong magnetic field exert force of 1 kg

TaimoorK56 months ago
ArtG12 years ago

•Does the number of coils that is wound to the metal bar affect
the strength of the electromagnet?


The higher the number of windings the more
"resistance" there will be within the coil. You actually want this.
This will slow down the drain on the battery while allowing the magnet to
remain strong: more electrically eco. (It may cost more in the short term).

•Does the wire gauge (20, 24, 28, 30, 34, 36 wire gauge)
make a difference is the strength of the magnet?

Yes. (Electric economy again)

This can be understood better with the idea of filling a
pipe to a certain water pressure (voltage = water pressure).

The wider your pipe, the more water it will take to fill it.
This matter more if you are turning the power on and off, but still makes a
difference while on due to the impact of the current (same as water current). Putting
a resistor will also help to slow down the amp impact.

•Does the voltage I supply to the coil effect the


Voltage is the electrical equal of water pressure. The more
pressure = the more power. The whole idea is to get very high voltage with very
low amps.

•What type of battery is best for an Electromagnet (AA, AAA,
C, D), and what voltage (1,5V, 3V, 4,5V, 6V, 9V)???

•Depends. Personally, I'd use rechargeable 9V batteries
because they can be easily linked together. They also cost less in the long
run, but bite in price at the start.

Another tip for making it stronger is to use small wire and
rap it in a single direction. By this I mean that you make a primary direction
of your wire. You rap it going in one direction (left to right, for example),
then when you reach the end, you bring it all the way back and continue the
next level till done. (This is patented by the way, so don't try manufacturing
this idea, but there shouldn't be any problem for what you seem to want).

An added benefit to this method is it allows you to make
(using DC current) an electro magnet which can repel a permanent one.

I did this with a McDonald’s straw as the air coil center.
When I took a group of those tiny strong magnets you can buy at Radio Shack and
placed them in a tall group they would jump out of the small straw when I
connected my 9Vs in series into it. Series = more volts; parallel = more amps.
For this to work the tower of magnets has to be higher than the coil of wire
for some reason.

I never tried to make two electros repel each other... yet.

I might try using high 20s gauge (maybe 30). Putting it in a
direction and using only a few 9v batteries at first. You can buy cases to
house other types of batteries, so I wouldn't get hung up on the 9Vs.

Radio Shack sells the cases. Look them up before deciding
which type to get. remembering that 9Vs don't require cases, first see if the
max voltage you can get from a case is enough for you, but try the keep the
amps low.

If you have the time and don't mind the effort, making or
getting volts increasing device would be a good idea. Or an outlet DC power
supply with higher volts and lower amps would be great. Hundreds of volts at milliamps
would be wonderful. This would really need smaller wire because of the
"pipe filling" effect I mentioned before. It will reach full power
eventually anyway, perhaps, but less eco.

I loved your story about a McDonald's straw. In fact, that's exactly the sort of thing I'm looking for. Something that can move less than half an inch when current is applied. All it will do is pull a tiny hinged door open for about 10 seconds, then a small spring will retract it when the current is turned off. (Think cuckoo-clock door.)

Your straw project fits perfectly with what I need to do. Now to the Bat Cave to build my tiny linear motor. Woo-hoo!!!

DustinS2 ArtG12 years ago

Wrapping the coils in one direction's is a new concept to me - do you know what patented talks about it, or what the process is called? I would like to read more about it.


this concept should be self explanitory. the reason for this whole thing is to create a magnet from electricity. a magnet has a north and south pole. we know that magnets are materials in which the polar alignment of the atoms are all pointing in the same direction. this concept uses the revers of electromagnetic induction. by passing a copper coil over a magnet really fast. the magnetization of the coil from the north and south poles, combine to create an electric charge. so here, we are doing the reverse. using an electric charge to creat a magnetic field. So if you want a stronger, more stable magnetic field, then like in a magnet - all the atoms should be polarized in the same direction. the best way to do this, is to make sure the electric current is constantly flowing in the same direction.

JerryP1 ArtG12 years ago
I made a air coil center 50 turns, 5 rows 24 gauge using a 12 v 1.75 A dc power supply and I couldn't move a small screw and I need to re pail a 1/4x1/4 super magnet so how big do I need to make this electromagnet ??? Jerry

okay first, you dont have a super magnet. you are most likely talking about an neodymium magnet. secondly, make sure your wire is coated. if it doesnt have rubber insulation, make sure it has an enamel coating. secondly, you have to REMOVE this coating from the end, in order to effectively connect the power supply. not only that but you are using low voltage. 12v, and you think you can get away with an air coil? there is a reason the article said to use an iron core. im not going to type it all out, so here is a copy and paste

Many electromagnetic coils have a magnetic core, a piece of ferromagnetic material like iron in the center to increase the magnetic field.[11]
The current through the coil magnetizes the iron, and the field of the
magnetized material adds to the field produced by the wire. This is
called a ferromagnetic-core or iron-core coil.[12]
A ferromagnetic core can increase the magnetic field of a coil by
hundreds or thousands of times over what it would be without the core. A
ferrite core coil is a variety of coil with a core made of ferrite, a ferrimagnetic ceramic compound.[13] Ferrite coils have lower losses at high frequencies.

TomK781 year ago

Here is a link that just gave me a great perspective on coil magnet strength. The smaller wire has more resistance but will require more turns and will stay cooler.

Heavy wire has less resistance but will get hot and can only stay on for limited time but will use less wire turns. Hope this helps.. Here is the link I found.

http://www.coolmagnetman.com/magdcem.htm for the information. I took you right to the experiment and calculations of the question but the home link on the top right will lead to an enormous amount of magnetic information.

SanjayS67 TomK7811 months ago

Why are the smaller wire coils cooler when they have more resistance?

they dissipate heat faster as the electrons are slowed. More current more heat. Moving electrons generate heat.

Very good question. There are two electric formulae which if you can remember them will answer 90% of all your electrical questions for the rest of your life.

1) V = IR

2) P= IV

So, 1) V = IR, voltage = current X resistance

Lets swap that about a bit and solve for current:

I = V / R

So the current = voltage divided by resistance.

So, as resistance goes up, current goes down.

Let look at equation 2) P=IV

Power = current x voltage

Almost all the power in a magnet ends up as heat so as Power goes down, heat goes down.

So, if you increase the resistance (thin wire) you decrease the power and assuming you don't change the voltage you will get less heat.

Thank you so much for the link and I really appreciated that you took the time to respond. Thanks AL.
DanielH3838 months ago

im curious if using a denser wire like iridium or platinum would make a difference, I mean it should in theory because the electrons pass faster.

RicardoM14811 months ago

Has any one used Energizer A23 Battery, 12 Volt

This is no good as a source for an electromagnet. I've used it and there's not enough milliamps in an A23 battery to keep the electromagnet on long enough. If you only want the magnet to be active for a very short time (like 1-10 seconds) then it's ok. For anything more you will need more milliamps. I run my electromagnet from a 12v lithium battery pack with 3300 mAh.

RicardoM14811 months ago

I need to make 4 strong but light weight magnet that are 1.5 inches long. The type of type of situation that it will be put through is that it will be turned on for about 2 seconds then off. But it will need to be turned off and on about 10 times with a period of 2 minutes. Then it will be given about a 10 to 15 minute break when I can if need to change out the battery. i was thinking about using a 9v or a Energizer A23 Battery, 12 Volt. does any body have any suggestions on what type of battery or wire to use.

PS: it is on a moving object so air can be redirected to force air cool it

Thank you

firestorm81 year ago

Get the thinest strip of copper wire you can get and preferably an iron core the size you want it to be. Then start to wrap the coil from 0.5 cm away from the end of the iron core. Continue until you reach the other end and the coils are only 0.5 cm away from the edge of the iron rod. Make sure to seal the whole thing otherwise it'll come off. And connect your battery. The more turns, the more powerful your magnet will be. I found this out through experience

I made coil of core length 28 mm and wire gauge 38 and 1850 turns but i am getting very less magnetic compare to other coil of core length 21mm, 28 AWG and 1000 turns.

Could you please sujjest what might me the problem. And current we are giving is up to 0.5 A.

MohammedZ31 year ago

diameter of coil wounding effect the electromagnetic field??

MohammedZ31 year ago

which type of wire is better for primary coil. i mean thick or thinner wire??

thinner is always better
go for a few layers; too many will take away from the conductance of the copper
higher volts = better
I'd go for nine if I were you
but listen, here's the thing
if you really want power for a split second, you might want to try to discharge current from a flash capacitor into the coil
(a flash capacitor is the kind found in the digital cameras)
that will give you a really strong jolt of magnetic tug
comodore (author)  The_Vinninator8 years ago
Hmm, that sounds like something i need....I need a strong magnet flash, but it has to happen like 1-2 times in a second...will it be enough to charge the capacitor? OK, nine turn....finally, some exact data! How thin would you go 32,36 gauge? Thanks The_Vinninator!
sorry, I didn't mean nine turns I meant nine volts but don't just limit yourself to that if you can combine batteries, that would be the best option your best bet would probably be to wire up a few nine volts in parallel what you would do is have more than one capacitor actually, can you tell me what you're using it for? that way, I can give you the best recommendation you want to go thin, but not so thin that it's resisting the current either 32 or 36 should work about the same anything else?
comodore (author)  The_Vinninator8 years ago
Well, I posted this question for a lot of reasons, got a big use in lots of my projects... But, right now I want to make an electromagnet inductor...whit a solenoid and a strong electromagnet.... the electromagnet goes into the solenoid and I use a bush button to turn on and off the electromagnet inside the solenoid and induct current....
in that case, I'd just go with what I told you a few nine volt batteries in parallel should work and ya... also make sure whatever you wrap the magnet around is clean and you don't want to have too many layers of wire because that brings the wire AWAY from the core would it be possible to avoid all this and just use rare earth magnets?
comodore (author)  The_Vinninator8 years ago
would it be possible to avoid all this and just use rare earth magnets?
  • well, yes, but I am working on a device and I need an electromagnet...so in this case no, but in other cases yes....
Thanks a lot! You really helped! :D
that's what I'm here for, bro *cyber high-five anything else, just pm me!
comodore (author)  The_Vinninator8 years ago
OK, if i have more questions and I probably will I will PM you or leave a question on your orange board...

Just 1 more question! :D
  • How many volts can I get from electromagnet induction, if I had a small coil whit more turn, thinner wire and a very strong electromagnet that is supplied with 9 V???
how many volts? It sounds like what you are saying is how much inductance (magnetism) can you get... inductance isn't measured in volts, it's measured in gauss I don't know how much gaussometers go for... honestly, almost ANYTHING can affect how much strength you get from the electromagnet don't expect to be able to lift a few pounds, but at the same time, if you make it really well, you might just be able to it's really too hard to say
comodore (author)  The_Vinninator8 years ago
No,sorry, you didn't understand my question... When I put an electromagnet in the coil and start turning it on and off...how many volts do I get from the secondary coil???
ArtG1 comodore2 years ago

that directly depends on the number of winding the two coils have relative to each other.

If the seond coils has more windings then the inducer, the voltage goes up.

Double the windings (number of layers) will basically double the voltage. The if the wire is wider than the inducer this will increase the amps.

I'm not completely curtain of the proportions, but I think it's roughly direct. That is, double windings = double voltage; and double thickness = double amps. This all assuming the impedance (coil resistance) doesn't make a big impact.

O that's what you meant... well, you would get the amount of volts in the power source minus the amount of resistance in the first electromagnet (you can test this with a multimeter) assuming you put it in series if you wire 'em up in parallel, you'll get the same amount of voltage in both (not taking into consideration any other factors)
comodore (author)  The_Vinninator8 years ago
Could you please take a look at my new question, I see you know quite a lot....
sure thing I used to work with electromagnets all the time in science projects
comodore (author)  The_Vinninator8 years ago
comodore (author)  The_Vinninator8 years ago
OK.... Thanks for your help! Keep in touch! :D
you're very welcome anytime
I'm sorry to interject but inductance is measured in Henries. Gauss is the unit of magnetic flux density.
you're probably right about that sorry but I don't really understand the difference care to explain?
hi Vinninator,

i've a problem with electromagnet, its rise time is 100 milli second while i need something around 100 micro second, i'm using steel nut 16mm dia as core, wire is awg 24, and resistance is around 10 Ohms
could you help me how to reduce the electromagnets rise time.

ArtG1 alpha552 years ago

since you already made the wire, I guess saying thiner is a bit late, so increase the voltage.

An easy way of thinking about it is to use water instead of electricity for thought purposes.

water pressure = voltage

water flow = current

resistance = resistance :)

you need to fill the pipe as quickly as possible to the currect pressure (same really in the end), so you need greater flow.

You will reach max a lot quicker if you increased pressure or flow, but only to the same pressure of your water pump.

Going back to magnets:

Increasing volts or amps will to about the same thing, but if you increase voltage, your max force will increase as well as the speed of increase.

So increasing eather will do, but voltage will allow for more.

You can see this quickly if you connect 9v batters to each other. One time only 2, the next time use 5 or more. There will be an ovious differance. Connected in series, the voltage is increase and amps remain the same. Parellel is the oposite. 3 x 9 = 27v and so on.

ArtG1 ArtG12 years ago


Too many volts will start to get dangerous, so get nervous and use electric safety if you really try the 5 or more. I did it up to 120v for my electro magnet test :D

And yes... I was nervous.

Make sure to stay that way when the emotions subside. I can kill you.

Even though amps are the killer (the actual flowing of electrons), they still use the punching power of voltage to break through skin resistance and reach the organs and kill.

Don't think it's still safe if you are dry with the higher levels of voltage. You cannot safely keep increasing volts at the same amps or lower. Be safe.

Inductance is the property whereby a circuit opposes a change in current. When it experiences a change in current it will produce a 'back EMF' or that will oppose the change. One example of the use of this is a starter coil in a petrol engine (diesel works by compression). A high current from the battery flows through the inductor, when this current is cut off, the inductor generates a high voltage in an effort to maintain the current. This high voltage pulse is allowed to arc over the spark gap and this ignites the petrol. The magnetic flux density is basically the strength of the magnetic field. S you can measure the 'strength' of a magnetic field at a particular point in Gauss (the Tesla is also a commonly used unit). AlexHalford
Are earth magnets stronger then an electromaget???. Thanks. AL.

You can always make an electromaget stronger, but Earth magnets are dangerously powerful. If all you know are the regular ones, be a bit nervous the first time you handle a rare earth magnet, or you could break it or even get a dangerous pench.

*than It all depends how much current, voltage or how many turns are in your coil.

Greetings Vinninator: I am in the process of building an electromagnet and would like your opinion on the materials I am going to use. I am going to use a u-shaped metal from an old lock that is long enough to use instead of a nail. I am also going to use a D battery and the wire looks like a telephone wire and it also appears to be insulated. I've read that insulated wire tends not to get hot as fast as other wires, I don't know if that is true, will see. So, what do you think???. Thanks. AL.
P.S. I saw a video of someone who used an electromagnet to pick and drop objects: How was that done??. Thanks. AL.

It's an easy question with a complicated answer. :-)

If you go to this page:

Dowload the file "Coildata excel file" and it will give you the ability to calculate how to build the optimal electromagnet given your size and voltage restrictions.

It's an easy question with a complicated answer. :-)

If you go to this page:

Dowload the file "Coildata excel file" and it will give you the ability to calculate how to build the optimal electromagnet given your size and voltage restrictions.

yaly5 years ago
too little coil will short the battery and they both eventually heat up too much and it drains the battery . wind neatly in only one direction use the thinnest wire you can find, wind several layers, use 6 D cells in series to produce 9v with enough ampere, you can use a simple method to calculate how much wire you need use a 10Kohm variable resistor and connect the middle terminal to the positive and the left to the negative use your hand to feel the temperature of the battery rotate the pot fully clockwise and then slowly rotate it anti-clockwise until the battery starts to get warm rotate it clock wise again until it stop increasing temperature, disconnect it and measure the resistance with a multimeter and wind the coil to that resistance the length of the coil must be short and the width must be long.
what is the right balance between resistance and current to save battery but get most magnetism. and if you have to get more turns around the spindle, there seems to be a balance issue for how thick you would like the wound spindle to be, i.e. how far away from the spindle the outer windings are and just lengthening the spindle.

it seems to me that while you can't wind thicker wire as tight you get less resistance from thicker wire so your are creating less of a heating element. and the heating would consume current. maybe this is a tradeoff between the ability to make close winds on a spindle with thinner wire even though it creates more load.

on the other hand, very little resistance means a lot of current will flow so you make more heat of a shorter or thicker wire on that basis even though its resistance is not high.

if you are not worried about residual magnetism, i.e. don't need the ability to turn the magnet off 100%, are spindle materials (or i'm actually looking material to extend the spindle to flat surface for a flat magnet parallel or perpendicular to the typical spindle, whatever is recommended, thinking trying to make a superstrong refrigerator magnet) that might actually offer enhancement of magnetic grip by developing permanent magnetism -- or possibly alloy/material that enhances the transmission of electromagnetic force.

if occasionally this permanent magnetism needed to be overcome for fine adjustments, i've noticed you can buy permanent magnet welding supports for holding two plates at right angles and you they have knobs for turning the magnets on and off.

thanks for any thoughts.

jwang20 yaly4 years ago
Apologies for randomly resurrecting this, but I have a question: How do you wind neatly in one direction and wind several layers? Once you get to the end of the nail or whatever, wouldn't you have to wind in the other direction to go back to the start?
They don't mean left to right, they mean clockwise/anticlockwise looking from the end.........
do u need the wire to be insulated or does it matter?
Yes, it needs to be insulated, because the electricity would just flow across, and not through the coils. Electricity takes the shortest route, or the path with least resistance.
now im confused. i took some thick copper wire and wound it around a railroad spike around 20 time and atached eac end to a car battery. it got extremely hot but it picked a magnet of mine off the ground from near a foot away. there wasnt any insulation :/ i dont understand how it worked for me
The electro magnet is not what picked the magnet up, it was the magnet that went to the railroad spike because of the iron in it.
this is extremely late but that isnt what happen. the magnet wouldnt pick itself up until about 3 inches away. i had it over a foot away and it didnt pick it up until i had it attached to the battery
Well Pyrotrician95, It must have of had a Thin, Translucent Coating on it Called "Lacquer". Which is a Good insulent for making electromagnets, The most used as well. So i'm guessing you got that wire from inside a Speaker, AC motor, or somthing with moving Parts...
yaly3 years ago
Of course it needs to be insulated, do not use less than one meter in length (wire before being wound), to wrap several layers and in one direction, wrap a layer then go back in a straight line then start another layer there will be a significant bump if you use thick wire, try not to align these bumps, use a soft iron core or an aluminium one so it won't be magnetized after disconnecting power. Please excuse my English.
akornblatt4 years ago
Hi. I'm also trying to build a small powerful electromagnet. I'm planning to convert it into a motor using the magnetic field to spin either a magnetically permeable material, or a permanent magnet. My current parts list consists of a few toroidal iron ferrite cores as well as a large tool steel core, magnetic wire, and about 4 9V batteries. Is there anything else I'm missing? Also, how many winds on the toroids would I need before I can see any really significant magnetic field? Is there anything else I'm missing? Thank you.
Also I kept all the magnetic wiring to 22 gauge.
NachoMahma8 years ago
> Does the number of coils...
. Yes. More = stronger
> Does the wire gauge...
. You can wrap smaller wire tighter (the closer the turns, the better). Since you are using 9V or less, the smallest you can get will probably work; as long as it will handle the current at the applied voltage.
> Does the voltage...
. Yes. The more voltage applied, the greater the current.
> What type of battery is best...
. A larger battery (C and D) will last longer and provide more current.
. Voltage will depend on the resistance (impedance, if using AC) of the coil and ampacity of your wire and battery.
  • You can look up the resistance-per-unit-length figure (eg, ohms/foot) for the wire you are using and compute the coil resistance.
  • As others have mentioned, a permeable core will help "focus" the field.
  • Google is your friend. Look for "DIY electromagnet", &c.

I'm also interested in building a strong electromagnet while trying to keep the weight down.

Googling around and I found this website for ...dum-da-da-dum... "Magnet Man" - Rick Hoadley.

The site has lots of science and exepermiments and all the equations you could need.  But check out the page on electromagnets

There's a downloadable "Coildata" spreadsheet to help you with the design - finding the right balance in the variables.

Simply save it to disk, and then open it. Fill in the data needed in the green boxes. It will calculate the length of wire in a coil, the resistance, and get an approximate inductance for an air core if you want to play with some numbers.

The speadsheet's a beast!  I was going  to dig out my old physics textbook and try to figure out the math - glad I found this site before I tried. 

thanks bro, it proved needy
comodore (author)  NachoMahma8 years ago
Thanks NachoMahma! It helped...I think I am going to use lots of turns and a very very thin wire...but low voltage like a 1.5 battery or maybe 3V.. Thanks!
mb inventor4 years ago
whenever i make mine i just wrap the wire arownd a nail and use a 9v battery for the power suply but its not the best way
hussainsk4 years ago
i was prepared to electromagnet 9v battery how much turns required 24 gage wire
I think coil amount does matter
dookie7915 years ago
I would recommend going to a scrap yard and taking apart a 2-3 ton refrigeration unit and then dissasemble the fan motor. And look at that! Four to five electromagnets are in there, just waiting for you to use them.
-max- dookie7915 years ago
yes you need insulated wire. go to radioshack and find the magnet wire (enameled wire)

TheBoss20125 years ago
you are going to want to use a battery with the most amperes possible. also, you should use the thinnest magnet wire you can. (if you dont have magnet wire, use wire with very thin insulation.) and make the coil as big as you can.
try amazing1.com's electromagnet its powerful enough to lift a car
What about using carbide as a core for an electromagnet? It can withstand very high temperatures and is magnetic due to the cobalt binder used to make it.
rockplourde7 years ago
There is a way to build very powerful electromagnets without useing large amounts of power, without cooling problems. You wrap a soft iron core with hundreds of 20 inch strips of 33 gauge magnet wire. clean the insulation off the ends of all the wires and solder all the ends together so you end up with somthing that looks like a braided cable. this cable will have a very low resistance. You wrap the cable around your soft iron core. so you basicaly have a soft iron core with many turns of this fine wire that are combined into a cable. This electro magnet has very low resistance and a large amount of ampere turns. requires a low amperage. A word of caution this makes a very powerful magnet, so be very careful.
rockplourde when you said "20 inch strips of 33 gauge magnet wire. clean the insulation off the ends of all the wires and solder all the ends together so you end up with somthing that looks like a braided cable". do you just solder each end to the next one like a long cable im not sure what you mean by braided would i braid the strips
legionlabs7 years ago
There is a wonderful technology called an electric double layer capacitor (also known as a pseudocapacitor).

You can buy a 2.3 volt 120 Farad (not a typo) device for around 16$, it is slightly smaller than a 9v battery. You will also need a 2V voltage regulator to charge it.

This will allow you to apply much higher currents. If you need to control it, use a power mosfet. Keep in mind that energy stored in a capacitor is 0.5*(capacity)*(voltage^2). That is 240 joules in this case, be aware that this can output the energy fast enough to heat your electromagnet to red heat and set your pants on fire (if it is in your pocket).

To buy one, go to www.digikey.com and search for "pseudocapacitor".

Good luck Re: Awesome painful disaster.
It sounds to me like you should just buy a tattoo gun and use the EM/ Solenoid off of it. Comes with a plug in power supply, adjustable speed control... everything it sounds like you need. You can also buy just the parts you need, and save some money. Google it.
pw20098 years ago
The ideal practical electromagnet has a very low resistance. A ferrous core (such as a nail) and more turns will make it more directional, ie focusing strength in one direction at the expence other directions. Thinner wire allows more turns in the same space, but you get a higher resistance and therefore less efficiency. You need to compromise between overall size, number of turns, copper gauge and type of core. The simplest way to drive the electromagnet with a battery is by incorporating a series resistor or using thinner copper wire. A far more efficient way to drive the electromagnet from a battery is via a 'switching' regulator. This can convert the constant voltage of the battery to a constant current (at a very low voltage) at the electromagnet without wasting too much as heat. Using a switching regulator means that the electromagnet can be made to be much closer to the ideal without worring about the battery voltage, and the battery will last much longer. A simple switching regulator will work best using a battery of about 4.5V or more (but lower is possible). The downside is that a switching regulator is not a simple circuit, but it is something to consider if you REALLY do need a small and high strength electromagnet and a long battery life. As a guide, a switching regulator will need a high-current ferrite inductor, a fast power diode, a fast power transistor and a control circuit (usually one integrated circuit plus a few minor components). Sorry I can't supply a circuit diagram. You might find something on the internet.
Kiteman8 years ago
To increase the strength of an electromagnet, do as many of these as possible:

  • Put more turns on the coil (which may need narrower wire to fit more on the core).
  • Put more current through the wire
  • Apply more voltage
  • Use a ferrous core.
How far you take these depends on the space and battery you have available.
comodore (author)  Kiteman8 years ago
Thanks, but here is the thing, as I sad, I need to use the smallest voltage that I can use, in a way it has to be energy efficient... Thanks!
The trick is to find a balance between the four variables.
comodore (author)  Kiteman8 years ago
So, what you are saying that I can actually put too many turns, or to thin wire?
More turns = more wire = greater resistance = less current = weaker magnet.

Thinner wire = greater resistance = ...

But, at the same time, more turns = greater concentration of magnetic field.

Like I said, balance. Kelseymh will know more about this, but it's worth playing with for your own education - try different coil configurations to see what works best.
comodore (author)  Kiteman8 years ago
Yea, I see... Also, there are some comments that say that the wire and the magnet will get very hot very quickly...is there a way to make it so that i can stay on for hours...??? Thanks
Not with a normal AA battery - a coil of wire is effectively a short-circuit, so an electromagnet will kill off a battery in short order.
comodore (author)  Kiteman8 years ago
hmm...who can this be avoided, whit out the battery or....?
Maybe add a resistor?
comodore (author)  Kiteman8 years ago
...yea... Today, I tried to make one but it was very weak...but...I only had two turns whit thick solid telephone wire, on a small piece of metal... I need the electromagnet to make a Faradays device that makes AC current... you know the device, whit a coil and an electromagnet inside and i repeatedly turn on and off the electromagnet and get AC current coming from the coil... I tried that whit a small coil and an electromagnet, but got a very strange result... When i was turning on and off the electromagnet inside I didn't get any AC voltage and as soon as I disconnected one wire from the coil from the multimeter, the current jumped to 2 V AC and started to drop very very slowly, about 0,01 volt per 5 secs....than I connected the wire back to the multimeter and again 0.00 volts! How is that possible???
The meter can be a fooler... it can pick up voltage out of the air. I think my previous comment got eaten, but what I said was that the more turns in the secondary, the higher voltage you'll see from your electromagnet being turned on and off. If you leave the electromagnet on, your secondary will show nothing. It is only when turning it on and off that the secondary voltage will be seen. 2 turns is probably not enough to see anything on the meter.
Seriously, you need to ask kalsyhm.
comodore (author)  Kiteman8 years ago
OK, I will! Thanks!
comodore (author) 8 years ago
hmm...that posts a big problem for my project, than again...it will be turned on and off every 0.1 or less seconds for about, again 0.1 seconds.... I don't know what i am going to do...i will get on to some tests and see... Thanks!
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