Questions tagged [coil]
A coil is an electrical conductor such as a wire in the shape of a coil, spiral or helix. coils are used in applications where electric currents interact with magnetic fields, in devices such as inductors, electromagnets, transformers, and sensor coils.
576
questions
0
votes
3
answers
26
views
Amp and voltage effect on solenoid coil
If I have battery of 7.4 V and 10 A = 74 watt connect to solenoid coil.
And if I have battery of 12 and 6 A = 72 watt (almost 74) connect to solenoid coil.
And they are under same situation (same ohm, ...
2
votes
2
answers
112
views
Why is my maths saying that increasing turn count will decrease magnetic field strength in an AC coil?
I’m trying to make a device that can propel rings of conductive material upwards and make them hover, like the one seen in this video at 6:24, albeit on a smaller scale. I got a stepdown transformer ...
- 135
1
vote
3
answers
72
views
AC coil heater vs DC coil heater - efficiency improvement
I am trying to improve the circuit of a coil heater which operates at 230VAC input. Total power to the coil is 2000W. There is a thermostat which measures the coil temperature and there is a relay ...
- 13
0
votes
0
answers
63
views
Is this current reading of my power supply correct?
I have built this simple ignition coil driver to test old ignition coils I have. I added R7 to match the drain to source resistance of the mosfet in my real circuit which is a p10nk70zfp. The drain to ...
- 43
0
votes
1
answer
81
views
Connecting 2 layer PCB coils together
I'd like to make a single phase generator with permanent magnets and coils in order to generate electricity just with my hand.
I already made a disc with 8 holes to put neodymium magnets in it and a ...
- 3
0
votes
1
answer
49
views
How doest this PSC multi-speed motor circuit work?
I've been replacing the thermal fuse of my fan blower each time it trips (every year or so, when the oils degrades).
But this year I decided to look at how the motor works. It has 3 speeds (slow, ...
- 3
1
vote
1
answer
113
views
How to improve a Tesla coil?
I've recently built a relatively big Tesla coil. It is a larger version of the Slayer exciter but with 2 big MOSFETs. The same circuit, with a smaller coil produced small arcs without a top load, and ...
- 27
-1
votes
2
answers
76
views
Does the diameter of a coil affect the voltage it generates when a magnetic field passes it?
If two wires of equal length (let's say 1m) are wound with different diameters (3cm and 6cm) to form a coil, if equal alternating magnetic fields passes through both of them, will they generate the ...
- 37
1
vote
3
answers
123
views
What limits the heating power output of a resistor heater?
I'm a bit confused since people said those resistors would draw more power the lower its resistance is, and one way to reduce its resistance is reduce its length.
Will it draw more power the shorter ...
- 49
-1
votes
2
answers
57
views
Unknown component from PSU. Transformer or inductor?
What is this component I salvaged from an ATX PSU? It looks like most inductors, toroidal in shape, however, rather than just one wire wrapped around the core forming a winding there are five.
I ...
- 11
0
votes
2
answers
60
views
DC Vacuum Contactor Coil - Failed Close
I am using a 350A DC, normally open vacuum contactor that experiences a failure while the contactor is closed (coil energized by 24VDC) for an industrial 1000VDC application. The manifests as the ...
- 1
0
votes
1
answer
42
views
Temperature measurement in strong AC magnetic field
I have a coil that is continously driven with a maximum of 100A RMS of current at a frequency of 20kHz. The coil is water-cooled and I would like to directly monitor its temperature. The temperature ...
- 31
1
vote
1
answer
31
views
Simple design for bidirectional current thought a coil
I have a coil made of a spiral PCB trace, with a measure inductance of about 20uH and resistance of about 10 ohms.
I want to be able to run, say, 200-300ma through the coil in either direction (the ...
- 55
0
votes
0
answers
46
views
Planar PCB inductor coil simulation
I am working on a planar PCB coil with a complicated shape (not the traditional circular/rectangular spirals.) It is essentially an inductor made out of PCB traces. I want to figure out the inductance ...
5
votes
1
answer
121
views
Calculate coil impedance, inductance and resistance
The voltage over a coil is u(t)=100⋅sin(100t+pi/3) V and current through it i(t)=20⋅sin(100t).
First off let's calculate the impedance, I'm quite sure I'm correct on this one.
This is where I get ...
- 93
0
votes
1
answer
71
views
MX-FS-03V 433 MHz transmitter will it function with a coil missing?
I'm planning to make a project using the MX-FS-03V 433 MHz transmitter and the corresponding MX-05 receiver with a couple of Arduinos for short range radio communication. Range will be at most 10 ...
- 117
0
votes
2
answers
101
views
Is it a good idea to drive 24VAC solenoid valves with triacs?
I want to build irrigation system for my garden. Most solenoid valves for that purpose work at 24VAC.
I'm wondering if I could use triacs to drive them. They are cheap and small (in comparison with ...
- 5,764
3
votes
1
answer
75
views
Simple wireless charging standard as used in toothbrushes?
I have a project that requires wireless charging of a small hand-held controller with a single 1S lithium-ion cell. People's initial thought was to use the standard Qi mobile phone chargers to save ...
- 6,629
1
vote
3
answers
156
views
Driving Ignition Coil with Microcontroller
I am trying to design a circuit to drive an ignition coil in an automotive application using a microcontroller. The microcontroller operates on a 5VDC input and puts out a 3.3V and 4mA digital signal ...
- 33
1
vote
1
answer
64
views
Switching transistor for micro solenoid
You may have seen some previous posts of mine asking various questions about frequency dividers. I have a circuit I think I am happy with for producing at 1Hz 12.5-25% duty cycle.
I now would like to ...
- 41
0
votes
1
answer
62
views
How can I make a 50mH inductor/coil that can stand up to 3A current to be used as a DC inductive load?
It will be used to simulate an inductive load for a DC output.
- 69
-2
votes
1
answer
77
views
Coil former footprint?
I am not sure how to make the footprint of this EP10 coil fomer as there is no guidelines in the datasheet. I am meant to assume all EP10 coil former have the same footprint?
https://www.digikey.com/...
- 113
0
votes
2
answers
49
views
Determining the type of magnet used in a hand-crank torchlight
I'm trying to design a DIY dynamo that recharges a 5V battery used to power some sensors. However, I am having some trouble with deciding on the arrangement of coils and magnets. Currently, I am ...
6
votes
1
answer
502
views
Why is the stator coil wrapped with layers of metal disks instead of a whole metal block?
I don't know if this question belongs to this forum, but I just saw this video and found out that the stator coil's armor (? - or something, I don't know the word) is made of layers of metal disks, ...
- 171
0
votes
2
answers
75
views
How to Limit Current Using L293D?
I’m designing a circuit to control 4 electromagnetic coils and subsequent orientation of a sphere (pic attached below). I’m new to EE but thanks to this forum I’ve learned what and how to utilize PWM ...
7
votes
4
answers
653
views
Fast coil decay
I have circuit where I need to fire electromagnetic actuator fast. If I need to go faster strike I need to increase voltage. But what about freewheeling inductor energy.
In circuit A the energy is &...
- 71
0
votes
0
answers
54
views
Possibility of achieving magnetic levitation(Arduino) with just one solenoid and a ring magnet?
I am currently working on a magnetic levitation project and have been looking into all types of magnetic levitation. One particular video I found around the subject was this: https://www.youtube.com/...
- 211
1
vote
2
answers
117
views
Calculating number of turns an electromagnet has
The title, but can one calculate the amount of turns on a coil or find that out somehow? Because I purchased a 120m copper coil (originally intended on using it on another coil former before giving up ...
- 211
3
votes
2
answers
123
views
Does same pole magnetic field flow past each other in a iron core
In a textbook transformer design like the one in the image, if I put DC current on both coils making sure that they both have the same poles on the same side, for example, they both have north poles ...
- 37
1
vote
1
answer
228
views
Metal Detector Coil Design
I have finally settled on a metal detector design on mine will be based on with one big issue,
(Tx wire diameter: 0.6mm, Rx wire diameter 0.3mm, 55 turns each)
I would like to increase the coil size ...
- 478
3
votes
2
answers
99
views
Increase magnetic power from a coil
I'm building a project which basically consists of the electronics inside a lucky cat: a coil that generates a magnetic field to make a permanent magnet move, which is attached to a swing. Check this ...
- 31
1
vote
1
answer
97
views
Ferrite rod (loopstick) antenna directivity
In a video about ferrite rod antennas it was stated that the antenna is most sensitive to the direction perpendicular to the axis of the rod, and it is insensitive along the axis. These are shown ...
- 1,247
2
votes
1
answer
143
views
Why doesn't magnetic power transfer use ferromagnetic cores in the coils?
One well-known fact is that putting a ferromagnetic material in an inductor will increase the magnetic flux and thus the inductance value.
Wireless power transfer (WPT) happens through the magnetic ...
- 1,247
1
vote
1
answer
45
views
Need some help with design for reduced friction acceleration of a ferromagnetic mass through a barrel
I would like to levitate (by that I mean just enough to not make contact with the surface of the barrel) and accelerate a ferromagnetic mass along a barrel of a certain length. I have a few questions ...
- 11
-2
votes
2
answers
72
views
How to use this 2 coil motor as a hand crank?
I found this used motor coil and got a few questions on how I can make it useable as a hand crank.
There are 2 coils with respectively 2 wires each. How exactly do I know the way of how each coil ...
- 3
1
vote
3
answers
115
views
How to trigger an 8 channel relay module with an air coil and moving magnet
I just bought this 8 channel relay module on Aliexpress, and I'd like to try to trigger it using an air coil and a moving magnet, but I'm unsure how to connect the coil to the trigger and collect the ...
- 119
1
vote
3
answers
109
views
Show polarity of magnetic pulse using two LEDs
I have made this simple circuit:
In response to a rapidly changing magnetic field (pulse), the LED blinks.
An example of the pulse is shown below:
Now I would like to have a circuit with 2 LEDs so ...
0
votes
1
answer
101
views
How does a relay behave when its resistance is increased or decreased? [closed]
I have a relay of coil resistance 200 ohm whose input voltage is 12V DC.
Now, under the same 12V DC supply, will the relay be activated when:
The relay coil is decreased, say by 100 ohm i.e. new coil ...
- 27
0
votes
1
answer
78
views
Determine inductance of large inductor
I asked a similar question before but i am still struggling with this problem.
I am trying to measure the inductance of a large (34cm diameter) electromagnetic brake.
Important findings to keep in ...
- 209
0
votes
0
answers
97
views
Can voltage be increased without coils?
I have a $5 solar lamp.
I have recently repaired it. It has a 1.5V rechargeable battery, a small solar panel, a yellow LED, a power switch, a transistor, a diode and some resistors.
I am a little ...
- 509
0
votes
0
answers
69
views
How to determine electromagnet air-gap using current waveform
I am trying to determine the air-gap of between an electromagnet (coil diameter 34cm) and a metal armature using the current waveform.
In the figure below you can see the charging curve of the coil ...
- 209
1
vote
0
answers
127
views
Determine electromagnet inductance
I am trying to measure the inductance of a large electromagnetic brake (coil diameter 34cm).
I used two methods:
LCR meter (100Hz because the brake is activated using a rectified 50Hz AC voltage) (...
- 209
0
votes
1
answer
100
views
Is it possible to use 48V relay in 120V circuit by adding current limiting resistor and capacitor. Will this also speed up the response of the relay?
simulate this circuit – Schematic created using CircuitLab
title kinda says it all,
Was talking to another engineer and didn't quite follow how they said they could get faster trip coil response ...
- 197
1
vote
1
answer
52
views
Current draw of a bilge motor [closed]
What happens at the coil when an electric bilge motor is stuck and stopped from spinning and the current draw increases beyond the rating (from 2 A to 8 A)?
- 11
0
votes
1
answer
101
views
Is this ringing a problem after "Relay coil fast demagnetization". If so, how to stop
In the question Relay coil fast demagnetisation, a diode and a zener were used in series to quickly remove the energy from an inductor. The question posed an example of a 24VDC 400mW relay, and I ...
- 1,999
4
votes
5
answers
243
views
Relay coil fast demagnetisation
In the past few days, I've encountered an application note on the Maxim Integrated website about rapid demagnetisation of an inductive load:
https://www.maximintegrated.com/en/design/technical-...
0
votes
2
answers
67
views
Coil generator in practice
I am trying to create something like gyroball. Which features LED lights, so the faster the spinning, the more light LEDs emit. This seems like a simple scenario of a coil generator.
As an experiment, ...
- 121
0
votes
1
answer
55
views
Using a signal generator and power amp to supply >>240VAC to a coil
On Lenz's law, Wikipedia says:
Faraday's law states that the EMF is also given by the rate of change
of the magnetic flux where epsilon is the electromotive force (EMF)
and \$\phi_B\$ is the magnetic ...
- 185
0
votes
1
answer
91
views
Total force made by the magnetic fields and the current, it should be zero but as I tried to derive it , the upward components only remains
As shown in the above diagram , the same 2 coils of square are aligined with paralell of same plane .
$$ I:=\text{current which flows to each wire of the square } $$
What I am confusing to ...
1
vote
1
answer
171
views
Determining an industrial electromagnet coil's number of turns and wire diameter, etc
I'm a new graduate and fresh hired Electrical Engineer who works in a company building magnetic separators for general industry (including mining, recycling etc.)
Normally, we build magnetic ...
- 11