1
vote
1answer
42 views

Magnet strength in dynamo design

I come from a computer background, and apologies if this question sounds elementary. While designing a dynamo, I came across a problem of how to calculate the the strength of the magnetic field, and ...
1
vote
0answers
37 views

Is it necessary for EM fields to be dependent & co-exist in static conditions? [closed]

I was having a discussion today with one my colleagues in the lab about the independence and co-existence of EM fields. My argument: In time-varying fields: EM fields are necessary dependent, and ...
2
votes
1answer
52 views

Electromagnet for string vibration

I recently read a lot about guitar sustainers, for those who don't know what are they - it is basically an electromagnet with an amplifier. It takes an input from pickup, amplifies it and then ...
7
votes
1answer
297 views

How does this iPhone app measure the power flowing through an AC appliance cord?

My electric utility released an iPhone app called "DTE Insight" which (among other things) measures the amount of power flowing through an appliance's power cord by asking you to hold the cord against ...
1
vote
2answers
75 views

How does the shape of the coil relate to the magnetic field around it?

I want to know if the shape of the coil affects the path of the magnetic fields around it. The two different shapes that I have are Helical coil and a spiral coil (in a plane).
1
vote
1answer
106 views

Help building electric generator? [closed]

I am in the process of building an electric generator for the first time, and I have found out most of what I need to do, except the following things. Can I have 2 rows of magnets linked together ...
2
votes
1answer
103 views

Increasing the surface area of an electro magnet

I am trying to design an electro magnet with a large surface area at the end. The first design used a 1/4" rod wound with magnet wire resulting in about 10 ohms of resistance driven with 12 V. This ...
0
votes
1answer
184 views

How to design a magnetic vibrator?

I plan to create a magnetic vibrator to shake a small container. What I plan is to buy Two "Magnet Wire 14 AWG Gauge Enameled Copper 1.5lb 118ft 200C Magnetic Coil Winding" a custom made container ...
1
vote
3answers
82 views

How to detect non magnetic material?

I want to design a paintball counter. I have a metallic or plastic tube through which a paint ball passes. How can I detect that the ball passed? What kind of sensors do I need? I cannot see the ...
2
votes
3answers
500 views

My DIY solenoid does not work

DESCRIPTION: Hi there, I don't know lot about electricity and I`m having problems with my first solenoid-prototype, I tried to build it watching you tube videos. I have attached the pictures of the ...
1
vote
1answer
79 views

When -EMF is induced can we keep current the same?

I'm confused at how Back EMF or (-V, -EMF) reduces current, and conserving the overall power. Let use the following simple example to help my understanding: A solenoid produces a magnetic field B, it ...
1
vote
1answer
160 views

How internal capacitor stud finders work?

I don't understand how can a non magnetic object like wood be detected using a stud finder For instance, stud finders find wood from dielectric constance, but I don't understand the princible. The ...
2
votes
2answers
109 views

Back EMF and opposing current of a super conductor?

A 5 meter long super conductor carries 100 Amps, and it passes through a 1 Tesla magnetic field at 0.010 seconds, Is EMF = - (BL) / (t)? And since the resistance of the super conducting wire is zero, ...
0
votes
1answer
95 views

Powerful electromagnet?

Is it possible to produce over 1000 lb of magnetic force over a distance of 4 inches(0.101 meters), using an electromagnet? How difficult would it be? Explaining the general spec's of such an ...
0
votes
2answers
66 views

Resources for ferromagnetics

I am looking for experimental data on the experimental strength of magnetic fields inside ferromagnetic materials. Here is what I mean. If all of the magnetic moments of the molecules are aligned in ...
1
vote
2answers
151 views

Curie temperature

Does a ferrite core (or other material) have their magnetic characteristics changed when they reach curie temperature and goes below it (considering it does not suffer any mechanical damage from that) ...
5
votes
5answers
449 views

What is the difference between the magnetic H field and the B field?

Wikipedia provides a mathematical explanation. Can I get the intuitive one? I'd like to, for example, understand a ferrite datasheet. These usually have graphs of H vs B, and the definition of ...
3
votes
2answers
86 views

Homebuilt magnetic tape head

I have seen a lot of projects that use a tape head, but there is very less information about how to build one yourself. Is this possible? I know that basically it is a metal core, with a coil around ...
0
votes
1answer
120 views

Magnetic Equivalent Circuit

Is this correct magnetic equivalent circuit for this electromagnet system ? simulate this circuit – Schematic created using CircuitLab And i am trying to solve it like this example, ...
-1
votes
2answers
108 views

Electro-magnetism. What's it all about anyway? [closed]

Ok, so am new to electronics. I've been looking up various thing like basic theory, schematics, circuit components, logic gates, and the rest. So all of that (on an extremely basic level anyway), I ...
1
vote
3answers
200 views

What mechanism happens inside an inductor from the point when potential difference is applied?

What happens when a potential difference is applied across an inductor? I am trying to get a picture of mechanism from start, just after potential difference is applied in detail? In resistor we can ...
1
vote
0answers
90 views

Ground plane and magnets

I am making a wheel encoder out of a Hall Effect sensor with magnets in a concentric circle on the wheel. The Hall effect sensor is on a 2-layer 9x5mm pcb. I usually fill in the layers by drawing a ...
0
votes
3answers
243 views

Electromagnet duty cycle

I have a project where I would like to use an electromagnet to lift an item for a longer period of time. I was looking at a magnet like this one: ...
2
votes
1answer
115 views

Electromagnet interference with motorcycle

I just got a sport bike which the frame is aluminum the engine is aluminum the swing arm as well. Basically this bike is made up of mainly aluminum and plastics with very little steel or any other ...
1
vote
1answer
588 views

Amperian loop to measure solenoid's magnetic field

My textbook proves the formula \$B =\mu_0In \$ for a solenoid by taking a rectangular Amperian loop as shown here: The problem I see with this though is that it only takes into account the ...
0
votes
1answer
477 views

magnetic field outside solenoid

It is written in our course book that the magnetic field outside a solenoid is negligible and almost zero. Why is it negligible? Is it negligible compared to the field inside solenoid or is it nearly ...
8
votes
1answer
490 views

Differences between a planar coil and coplanar waveguide to create a local 1D AC magnetic field

Coplanar waveguides (for example picture look here) are often used in research to create a local in-plane magnetic field. Now if compared to a planar microcoil like this, driven by a AC voltage in ...
3
votes
3answers
2k views

How to convert a three wire hall effect sensor to a 2 wire sensor?

Would there be any possibility to convert a three-wire hallsensor to a 2-wire equivalent. The connections are a V+, GDD and OUT. The voltage between V+ & GDD would be 24V and the OUT port would ...
3
votes
1answer
162 views

Automobile ignition coil (spark coil)

Question: How is this possible to get 1:1000 electric potential scale while primary/secondary loop scale is only about 1:100?
2
votes
1answer
218 views

Controlling temperature of a water bath with induction plate

I am thinking of building a sous-vide cooker using some kind of prebuild heater, controled via an AVR and temperature sensor like the LM35. There are a lot of references around using rice cookers, ...
0
votes
1answer
388 views

Building a coil for galvo motor

I'm building myown galvo motors and for that I need some coils that I'll have to build myself to fit into the dimensions I need. Is there any technique for winding the wire or is it just straight ...
3
votes
2answers
364 views

Sending data over a magnetic field

I need to find a way to trigger this Hall Effect Sensor with a non-permanent magnet. Does anyone know if an inductor's magnetic field would be strong enough? Or am I going to have to build an ...
6
votes
1answer
138 views

Fine-grained sensing of distance between two permanent magnets

(disclaimer: bit of an electronics newbie here) I have a bunch of little magnet ball-bearings that I was playing around with the other day. I formed them into a strand, then fixed both ends leaving ...
8
votes
2answers
463 views

Using the audio input port as a voltmeter

I'm a physics undergraduate currently studying electromagnetism. I have no experience at all with playing with electronics. I'm trying to see the effect of a changing magnetic field on a closed ...
1
vote
1answer
451 views

Do diamagnetic material exhibit induction?

Silly question perhaps, but do metals with the property of diamagnetism also exhibit inductance? Would a fluctuating magnetic field induce a current in a diamagnetic metal?