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.
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What is the best way to multiplex 64 coils?
I'm trying to make a digital chessboard. The design consists of 64 coils, one under each square. A microcontroller's PWM sweeps the frequency over a given range, such as 50 kHz to 350 kHz. The signal ...
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Using MOSFETs to control series-wound flipper coil
I'm trying to control a series-wound pinball flipper coil using two N-Channel MOSFETs, like this:
The switches are mechanical leaf switches. The diode D1 is part of the coil assembly, I don't know ...
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Not getting spark from ignition coil test circuit
I have a simple circuit setup with an N channel MOSFET switching ground to a two pin ignition coil. I am not getting any spark from the spark plug in the coil. Could someone take a look at the ...
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Circuit to drive a high power high frequency electromagnetic coil
I'm trying to design a circuit that can drive an air-core coil with an inductance of 45uH. The coil has a resistance of 0.15 Ohm measured at 50 kHz. The circuit should be able to push up to 100A ...
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Is it possible to smooth out a power signal from a magnet being dropped through a coil?
I am wanting to try some experiments to see how much power can be generated using various magnets and coils, but my understanding is the voltage is positive as the magnet approaches the coil and ...
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RF coil is a capacitor
I have a coil, and I want to measure its inductance, however, for frequencies below 500 MHz, it shows capacitive behavior.
Is this a calibration error, or is it normal for a coil like this?
What ...
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What will happen if the Impedance of wireless power power transfer TX coil and RX coil are different
I am new to WPT. Currently I am characterizing the coils to be used used for our WPT.I measured the inductance of TX coil and RX coil at 100Khz.
The impedance of RX coil is 4.5uH @ 100Khz and that of ...
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Taking into consideration the information provided, would the motor output the intended power?
Well, I'm not an electrical engineer and I'm trying to design a direct drive axial flux brushless torque motor with 300 kW with little weight as possible.
I'm never going to actually build it because ...
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Induced EMF in a stationary coil
Suppose a there is a coil which hasvelocity=0 and we can say it does not experience any force due to themagnetic field. There is no role of induced EMF in any case. If we place a stationary coil and ...
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Driving relay without a control Fet: Back EMF consideration when control side is Grounded
I want to drive a G8G-1SV DC24 relay just by turning on/off its control side with 24V like this:
while following the recommendation from its datasheet for the back-emf protection:
My consideration ...
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Do wireless power transfer coils have polarity?
This question is a continuation of my previous topic.
I need to characterize this coil with the help of this document.
The coil will be connected to a BNC adapter and the other end of the cable is ...
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Conservation of energy during electromagnet repulsion
Scenario
Consider a coil with some internal resistance connected to battery.
To give some example values, let's say the battery has capacity 4 Ah and voltage 1.5 V. So the total energy of the battery ...
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Properties of coils used in a power transmitter and receiver
I am completely new to wireless power transfer. I need to model a wireless power transfer link with the help of a Bode 100.
This is the reference document given to me.
Before starting this, I would ...
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If the current through an inductor can't change suddenly, how it can induce voltage in the ignition coil of a car?
In an igniton coil, there is a voltage induced in the secondary when the switch is changed position. According to Lenz's law, the primary coil in the ignition coil will try to continue flowing the ...
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Normally closed relay failing due to shock and vibration
Relay in use:
https://www.mouser.com/ProductDetail/Omron-Electronics/G5LE-1-DC3?qs=Mrnyg3lK62ERI7jHW9tK%2Fg%3D%3D
Vin = 12V
Imax = ~5A
My application for the relay is to cut off downstream power with ...
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Calculate alternator power from open voltage and short current
A 3-phase BLDC motor, used as an alternator, outputs 3V open-circuit and 5A short-circuit at a given RPM. How can you calculate or at least estimate its useful power at that RPM if we connect it to a ...
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Will this circuit design of a simple slayer exciter circuit work?
I have been looking at different designs for a simple slayer exciter circuit and have attempted to create a circuit diagram for it based on what I have seen from some other designs online. I just ...
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Solenoid coil repairing [closed]
My change over JQX-62F-2Z relay coil burns.
So I want to repair the coil.
Please guide me about wire gauge and turns to repair my relay coil.
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Best method to dampen inductive spiking from pulsing coil with MOSFET?
A simple diode works across the coil to lower the voltage spikes, but I ideally need a way to absorb the inductive spiking as fast as possible. I've heard a Zener diode across the drain and source of ...
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Why does the STM32F030 hang when the solenoid Lock is activated?
The circuit consists of a STM32F030 and several 5 V relays, which are connected to the coil to open the door. The input voltage is from 18 V which is fed from a 220 to 18 V transformer (not switching ...
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Drive up to 64 coils (one at a time)
I want to drive up to 64 (PCB) coils at 5V / 200mA using a PWM signal from a micro controller. I only need to control one coil at a time. So I have two questions:
How can I multiplex the PWM signal?
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How can I calculate how much power an isolation transformer itself consumes if no load is provided?
Isolation transformers usually come with these measures:
Voltamperes
Voltage
Current
In my case, I want to know estimate how much an isolation transformer will consume without a load using these ...
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Turning a microwave transformer into an electromagnet
So I want to turn a microwave transformer into an electromagnet. I've already harvested the transformer, cut through the welds, and removed the coils. I want to know where to position the one coil ...
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Best way to generate a variable clean DC current
On one end I have an amArduino or other microcontroller. On the other end I have a small electromagnet coil with about 20 turns of 1 inch diameter. I need to drive this coil with some precision (say 5-...
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Places to harvest electromagnet coils [closed]
What are some common appliances or electronics that I can harvest a tightly wound coil and core from (like from a transformer for example)? I know about the dangers that come from messing with ...
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Can a coil reversibly modify the field of a permanent magnet?
If I have (say) a rod shaped neodymium magnet and wrap it with a coil, can I use the current in the coil to add to or subtract from the permanent magnet's field in a reversible manner?
Also, would the ...
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Example problem of induced emf in a 100 turn coil by a 100 turn coil which has 90kHz sin wave input voltage
Main Question: Let's say there are two coils each 100 turn and diameter 30 mm, And the second coil is perpendicular to the first coil's magnetic field (placed both coils next to each other; we can see ...
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PCB Coil Inductance Calculation
I am designing (noob electronics engineer) an inductive position sensor using Renesas IPS2200 (https://www.renesas.com/us/en/document/dst/ips2200-datasheet).
The sensor requires a PCB coil (L in the ...
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Example problem of induced emf in a coil rotating in the earth's magnetic field
I just recently learned magnetism-coil-faraday's law and I want to do some real world problem solving.
Question: Let's say a copper wire coil (20 mm dimeter (r=10 mm)) of 3 turns (N=3) is on the ...
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I'd like to make a wireless charging pad
I would like to implement a wireless charging system as my graduation project.
The topology to be used is likely to use the "SS compensation" topology.
The problem is, we have to design the ...
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Identifying and designing coils for generating parallel magnetic fields with smooth gradients
What is this coil called (see image) (blue line is field, blue circle is clockwise oriented coil, red circle is counter-clockwise oriented coil), and are there any tools that help design it?
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Why does the Inductance change on an E-Core Leg when going from Small Copper Wire to Litz Wire?
In the first picture you can see 45 turns of standard 0.4 mm copper wire. The impedance analyzer (e4990) shows an inductance at 20 kHz of 11.5 mH. Which is inside the tolerance of around 12.8 mH +- 20%...
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Identifying monopole antenna with ground connected coil
I can’t find any information on what this design of antenna is called, it has a monopole wire connected to the signal pin of an SMA connector, the coil is connected to ground. The larger diameter ...
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Core iron barely boosting field strength
I am a chemistry intern currently running a project that involves both chemistry and electromagnetism. Bottom line, I'm a little out of my depth and have much to learn, and I'm having a bit of trouble ...
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How to convert this 220V AC input inductive charger to 127V AC input?
My friend bought a device that has wireless charging, but in my country, in the region I live, the AC voltage is 127V , and she received (a long ago) by mistake a 220V AC input version.
She never got ...
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Thyristor blowing up in a coilgun
I am making a six-stage coilgun. I know the optocouplers are switched in the diagram, but the thyristors keep blowing up. They are blowing up randomly. That's my fourth thyristor I have replaced.
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RFID PCB coil output power much lower than expected
I'm working on a PCB for RFID reading and writing however after assembling the PCB I have noticed the output field strength of the RFID coil is much lower than I anticipated.
I was trying to copy the ...
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Is it possible to store energy in an air coil?
I just want to know if an air coil can store energy. Does it necessarily need to have a core material and air gap to store energy?
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DC-DC regulator power inductor alternatives
I am using Texas Instruments Webench power designer to create Dc-DC regulator circuit. Input should be 5-12 V and output should be 5 V 3 A. I am trying to look for cheapest design. Most of generated ...
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Inductor on a GPS receiver
I'm soldering the circuit of a high accuracy (and cost) GPS receiver with an active antenna.
The inductor L1 in this diagram has a polarity marked by a dark band on one end.
Which side do I put the ...
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High Switching Coil Current Circuit
I've been working on building a circuit designed to handle a 40 A current with a switching time of less than 1 ms (currently using 500 us). I've attached the circuit for your review.
Initially, I ...
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Grounding shortened vertical antenna with coils?
The calculated coil for 27 MHz shortened vertical antenna with the length of 5cm and 0.2 mm diameter is about 65uH. It is unrealistic with that bandwidth and efficiency, but it serves theoretical for ...
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Direction of magnetic flux in magnetic circuit
In the first picture attached,we see a ring shaped magnetic circuit with two magnetomotive forces. Now,in the solution to this problem,it was said that the two sources generate flux in the same ...
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Transformer derivation - reactance [closed]
I'm struggling to understand a detail in the derivation of the transformer: N1/N2 = V1/V2.
The start of this derivation is to state that the input voltage Vi is equal to the voltage drop on the ...
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Receive Antenna Design Consideration in Dual Antenna LF RFID System
I am working on constructing a loop antenna pair for an LF RFID application. The antenna is quite large (4' x 6').
I was able to successfully wind a transmit (Tx) antenna and tune it such that it ...
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How does the voice coil affect volume in DIY headphones?
I know nothing about electrics. I am learning some very basics by making a pair of incredibly simple headphones with a 3.5mm jack, some enameled wire, some magnets, and some paper cups.
After a bunch ...
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NEMA Coil "Sealed Current"
I am trying to select a relay to interface between a temperature controller output and a NEMA size 4 120VAC contactor coil. According to the NEMA spec, a 120VAC, size 4 has a 8.3A inrush current and ...
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Designing Eddy Current Sensor?
I am looking to build a eddy current sensor, I am having difficulty finding information on how I should be designing the sensor to fit my needs. There's a few studies and articles I've found that ...
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Is it possible to "relay" a wireless (inductive) charger using two coils?
I'm on a quest to have an iPhone wallet case that supports wireless charging. I won't bore you with my long list of failures, but would love feedback on this strategy.
I 3d printed a case which puts a ...
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How to find the voltage of the coil in this RLC Circuit?
I am looking for the voltage of L1. What I tried to do is this:
Vsource = I(R1+R2+1/iwC1+iwL1+iwL2) Equation 1
Vsource = IR1+IR2+Q/C1+L1dI/dt+L2dI/dt Equation 2
Equating 1 and 2, I(R1+R2+1/iwC1+iwL1+...
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