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.

An electromagnetic coil is a device comprising two distinct elements: a conductor and a core. The conductor is most commonly made from solid copper wire, which is wrapped around a core. Each time the wire is looped around the core, it is called a turn. Multiple turns are considered to be a coil.

The most common use of an electromagnetic coil is that of an inductor that stores energy within its magnetic field. Considered a passive electrical component, an inductor has no gain and cannot control the directional flow of the energy. The way an inductor harnesses energy is by the electric current passing through its body.

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Why don't electrons take the shorter path in coils?

Below is a copper coil, presumably forming an electromagnet. From my understanding the electrons travel around the coil to produce a magnetic field. But why don't the electrons jump the wires and take the shortest path? Below I tried to draw the…
rrswa
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How to properly wind coils for a solenoid?

I need to wind a small electromagnet "solenoid?". About 3cm high and 2~5cm wide running at 5V/0.5A. This magnet will be put into a desk bell so it pulls the clapper down and rings the bell. I have found ready made solenoids that push out but not…
Piotr Kula
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If I used the primary coil as an inductor, does the secondary coil affect it?

I've read this question. It's about how to obtain the maximum inductance from a transformer: How do I use a transformer as an inductor? Now, I would like to use the primary coil only as an inductor to study some basics about inductors. I'm going to…
Michael George
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Why use aluminum wire in an (old) TV degaussing harness

I used to take TVs apart for fun (and parts, and learn.) Some of the degaussing coils were beautiful -- nice, thick copper. Others were made out of aluminum wire. If I were engineering it, though, I would not have even thought of aluminum…
MicroservicesOnDDD
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Controlling an electromagnet strengh with arduino

This previous question Controlling an electromagnet with Arduino deals with binary control (ON or OFF) only. On my side I need to choose the strength of the magnetic field. It is a home made electromagnet, I managed to power it with 12V DC + a 5ohm…
repied2
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Why do I need to remove a part of the insulation on a copper wire on a simple electric motor?

Why do I need to remove a part of the insulation on one end of a copper wire in making a simple coil electric motor? How does removing only a part of the insulator makes the motor spin freely? Reference at step 3. I know why the coil spins. What I'm…
Satou Kazuma
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H-Bridge with emitter followers

I am currently reverse engineering a circuit which requires controlling of a magnetic field. For that, the circuit has a pair of D882 and B772 each. The PCB traces suggest that the transistors are arranged as shown in the picture below: This…
aquaatic
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What are the differences between an AC and DC coil relay?

If a DC coil was just a coil, it would saturate. If an AC coil was just a coil, the magnetic field would drop to zero at 120 Hz and the relay would chatter. Presumably the designs in some way prevent these problems. How? And does it prevent me from…
Stephen Collings
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How to identify an ordinary coil? Can I use some tools do identify its value?

I did a big mistake and damage an electronic coil in my PCB. The only information I did have is the coil itself! There are two identical coil in it. This is my PCB. It is the UCD-210M. This is the broke coil And this is the another good one in…
Rodrigo
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Making a nail electromagnet with bare copper wire?

When creating a simple electromagnet, all you need is a nail and some copper wire, and a battery. I did this using non-coated copper wire, and after thinking about it for a bit, I was confused as to why it was working. Theoretically, the current…
vcapra1
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What do you call a relay that self-opens on power loss?

I'm programming the simulation of some circuitry. These are relays that will open automatically when they lose power: Do relays such as this have a particular name? "power hold relay"? "single pole relay"? "self-opening relay"? I see that…
Trevor Hickey
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Can the wire of a high voltage power line be used as the primary coil of an air cored transformer?

Back in the 90's I heard this story of a guy who in the 70-80's lived remotely near the power lines and that he was very good in electrical engineering and that he had free electricity by using the power line as a primary of an air cored…
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How susceptive is an inductor to frequency and current?

According to Coilcraft - Testing Inductors at Application Frequencies the inductance of a coil changes with frequency and current. Most datasheets don't give a frequency-inductance plot and current-inductance plot. Is there some rule/guideline to…
Henk
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When an electromagnetic relay is switched on, it shows a dip in the coil current for a millisecond but then increases again. why?

I am currently studying the effects of current on the coil of an electromagnetic relay and came across this graph: Image source: Ramirez-Laboreo, E., Sagues, C., & Llorente, S. (2015). A new model of electromechanical relays for predicting the…
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Coil suppression: Zener + diode: how to minimize the negative voltage?

I have come across these two app notes: Coil Suppression Can Reduce Relay Life Application of Coil Suppression with DC Relays Both of them agree on the fact that a common diode + Zener diode in series is the best solution for spike suppression all…
VoltsAndNuts
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