Questions tagged [inductance]

Inductance is the property by which a change in current in a conductor induces a voltage both in the conductor itself and nearby inductors, the latter being the basis upon which transformers operate. Discrete inductors are also available that have many applications including filtering and energy storage.

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43 views

Permeability Discrepancy of an Inductor

Background: I bought a material 77 ferrite rod for a homemade inductor. The core was 0.5" in diameter and 7.5" long with a claimed initial permeability of 2000. When I recieved it, I tested it out ...
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Is there a difference between read range and read speed/sensitivity in LF RFID applications

If I want to read 125kHz tags but my antenna oscillates at 130kHz, read range will suffer given that the antenna has a low enough Q-factor to still excite the tag at 125kHz. My question is, is there ...
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87 views

Making an Inductor with Proper Inductance

Background I am planning to build a 0.0625 mH inductor, which will be sent about 15 kV max (10 uS pulses, 10 per second). The inductor will be made of 14 AWG copper wire in a tub of mineral oil. The ...
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68 views

Substituting an inductor - cannot find any pieces containing inductance needed

I am a beginner electronics hobbyist trying to follow an old schematic / instructions to build a theremin. I have all of the pieces except one. This piece (Toko 154ANS-T1019Z) calls for a "68 µH, hi-...
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76 views

Why does inc R of a RL circuit increase dVL/dt. Here I have circuits and details

Why does increasing R of a RL circuit increase the rate of change of voltage across an inductor with respect to time dVL/dt. Here a 50V 2k circuit and a 5V 200ohm circuit both create a change of ...
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66 views

Solving for inductance L in an AC series+parallel circuit is .. quartic?

This seems like a painfully simple question, but I keep ending up having to solve a quartic equation. So I'm missing something obvious. Let's say we have a an AC source feeding a load consisting of a ...
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54 views

How inductance of a coil changes when there is a metal object nearby?

I am not sure if it is increasing or decreasing as some sources say it is increasing whereas some say it is not. What actually happens when a metallic object is put under a coil that is meant to be ...
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36 views

Is the transformer leakage inductance increasing or decreasing VS. size

I have built an sine filter for a small inverter that feeds a transformer 250VA. The filter is basically a LC filter, that uses leakage inductance of the transformer with a capacitor connected in ...
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169 views

What is an Evaluation Board used for?

I am currently working on a senior design project. I have always been a software person, but it seems that this project requires quite a bit of hardware knowledge. We are trying to measure respiratory ...
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40 views

Choose RF block inductor value

I have inductor to block RF. My signal is between 1 and 2 GhZ. How should I choose the value of this inductor ? 1µH is enough ?? What are the other parameters to take care about ?
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How to choose replacement capacitor/inductor in a simple RLC blackbox?

Assuming there's a circuit that we can't see but we can guess how it works based on what it's made for. We know (or just are pretty sure) it's an RLC circuit with no digital parts. From what I've ...
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How to minimize impedance from capacitor to Gnd and Power planes

I'm trying to minimize the impedance from my capacitors to the Gnd and Power planes. 1. Via positioning I've learned from several sources that the best via positioning is close to each other. This ...
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83 views

Op-amp inductive output impedance oscillation

In Learning the Art of Electronics pg.362, the author presents an op-amp follower driving a long cable. I don't understand the explanation given for the cause of oscillation. In particular, the author ...
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49 views

Equivalent Circuit of identical transformers connected in parallel or series

I'm trying to figure out how to solve the equivalent circuit for 2 identical transformers connected in series or parallel on the primary and secondary. Mainly I want to know what the equivalent ...
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73 views

Circuit Representation of an Unknown Switching Transformer (Including Dot Notation)

Is there a way to identify the phase of the transformer's coils without having to see its waveform in an oscilloscope? For example, I have this unknown switching transformer The only thing I know is ...
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63 views

Effect of drain inductance on MOSFET turn off

I have made a simple circuit in LTSpice to test MOSFET turn-off time. Inductance is changed from 1.5nH to 1.5mH in a few steps. The next picture shows gate-to-source voltage and drain-to-source ...
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63 views

Inductance of a single conductor

Which is the correct expression for the inductance of a single conductor? I see 2 different formulaes for the same in different sources. Formula 1. Ref: https://www.eeweb.com/tools/wire-inductance ...
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From a flux point of view, how can we explain that the equivalent inductance is half when identical inductors are connected in parallel?

The equivalent inductance of 2 identical inductance connected in parallel ( ignoring mutual coupling) is half of the orginal . This result is usually derived from the argument of identical voltage ...
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Simplifying electrical circuits

I have looked everywhere, but I can't seem to find a way to simplify this circuit. I wish i could tell you some of my ideas, but I'm really lost here, can someone help me? If you could explain how to ...
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53 views

How to calculate primary, secondary, and auxiliary inductance of this transfromer?

I am wondering how to calculate/find out the inductance values for primary, secondary, and auxiliary windings of a Würth Electronik 750310742 transformer. The main reason is so that I can attempt to ...
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27 views

4 Conductor System Impedance

I have a +25kV 0v -25kV conductor system, involving 4 conductors located within a 30m^2 cross sectional plane, for which I need to calculate the individual conductor impedance's per meter and need ...
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1answer
37 views

Split start induction run motors

I'm reading a book on split start motors where single phase ac is phase shifted by two inductors at different resistance and inductance. My question is how does this offer a 30-45 degree phase shift,...
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28 views

Current on each winding of a solenoid and wire selection

While I was reading an article about inductors and air core solenoids in general, I came across the term voltage per turn. Until then I thought that all of the windings of a coil are a continuous wire ...
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45 views

Polarity of the voltage drop on inductance

We know from the Lenz's law that the induced voltage on an inductance has the polarity that determines an oppisition to the variation that has generated it. But in circuit theory the inductance is ...
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42 views

Relay coil inductance variations vs. temperature

How does relay (something like this https://www.hobbytronics.co.uk/datasheets/songle-12v-relay.pdf) coil inductance changes with increasing/decreasing temperature? And how can we calculate the new ...
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56 views

Inductors, Inductance calculation

I try to understand inductors and inductance. I create a multi-layer circular coil with 35 turns of enamelled copper wire ~21AWG (0.75mm precisely) with a diameter of 8.5cm. ...
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55 views

Self Inductance in Steady State equivalent model of Brushed DC machine

The First pic shows the model of DC motor under dynamic conditions. The above second image shows the steady-state model of the DC motor. The image below shows the Simplified DC Motor by using a ...
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Calculate inductance for ESD protection

I am trying to use TMC2130 for drive a stepper motor that has attached with plastic pulleys assembly. According to data sheet I have to concider about ESD protection due to plastic rotating assembly. (...
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161 views

Why transformer is heating without load [closed]

I'm working as technician in computer store and I have a lot of scrap transformers . Most of them small and have 6-8 pins .I wonder, can I use them for my projects ? If I remember correctly these ...
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Can the power transfer ranges of wireless charging devices be extended to across a room? [closed]

Wireless charging devices charge devices by creating a magnetic field that induces an electric field in the device (like transformers), but its strength is inversely proportional to distance squared. ...
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49 views

Half Bridge Inverter Effect of Load on waveforms

I have made a half bridge inverter, in the lab and on simulation software. I have used the gate drive IR2110a and am supplying it with a square wave pulse and it is then applying the gate voltage to ...
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1k views

Why is the air gap between the stator and rotor on a motor kept as small as it is?

Between the stator windings and rotor is a small air gap. What would happen if this gap were larger than it is? Surely the magnetic field set up by energizing the stator windings would still cut the ...
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104 views

LTSpice: simulate transient voltage and current in RL-circuit

My goal is to calculate transient current and voltage in a following circuit: Also, immediately after the switch is closed, initial current is 0 and then it exponentially increases until the value ...
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143 views

Is back emf inductance in a ignition coil circuit symmetric for on/off cases?

I was trying to understand how an ignition coil circuit works practically, and came upon this website explaining the behavior of an ignition coil when subjected to changes in voltage: http://www....
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108 views

Transformer's Primary and Secondary Voltages

In general, which is the phase relationship between the primary and secondary voltages of an ideal transformer? Does it depends on the dot convention?
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23 views

How to archieve induction isolation from adjacent inductors on a plane, but no isolation from inductors outside the plane

I am thinking of designing a large wireless charging pad. The idea is to have many inductors in a grid setup, where when a phone is placed on the pad it starts charging from the inductors closest to ...
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673 views

Turning off (collapsing the field) of large inductors

In a totally unrelated search to something I was looking for, I came across an article from the EPA that describes looking at soil properties through a large inductor for geophysics. https://archive....
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93 views

Autotransformer vs Inductive Divider

Which is the advantage of using an autotransformer instead of a simple inductive divider?
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45 views

Series resistance for DC brushed motor with PWM drive

I'm looking for double-checking my math/assumptions, and if possible, a physical explanation of the "rising corner frequency" phenomenon. When controlling a DC brushed motor with PWM, typically by ...
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3answers
85 views

My push-pull converter uses a flyback transformer with an air gap. How does changing air gap size affect the secondary output voltage?

My push-pull converter circuit uses a flyback transformer with an air gap. If that air gap is changed (increased), the primary inductance is decreased. How should I expect the secondary voltage and ...
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116 views

Can a change in magnetic field change the impedance of a coil

I kept a coil in a linearly increasing magnetic field and calculated the impedance by measuring the induced current and voltage. When the maximum value of magnetic field was reduced (while keeping ...
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38 views

Total phase inductance of three phase reactor

Consider a three phase reactor (inductor) using E-I or E-E laminations with phase winding on each limbs. Now inductance of R phase is given by: Lr=Lrr+Mry+Mrb Lrr: Self inductance of R-phase Mry: ...
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229 views

Why is low inductance important for stepper motors? [closed]

I’m building a CNC style device and am in the process of choosing the right stepper motors. I read that it’s important to buy steppers with maximally 5mH of inductance. Why exactly is that the case? ...
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124 views

Electrical model of a transformer

I would like to know what is the inductance (circled in red) of this part of this model? Is the value infinite? And only the inductance (circled in blue) is the value of the inductance of the ...
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103 views

How to choose an inductor for a LCL filter?

I am trying to make a voltage generator. I used an inverter and it is controlled by a PWM signal. I used a LCL filter to filter the output signal since it is rich in harmonics but in the choice ...
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42 views

inductor/coil - time to reach a given current

I understand that there's a simple forumla for calculating the time it takes for an inductor to reach 63.2% of it's maximum current: t = L/R But is there a way to calculate how long it would take to ...
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106 views

Eigenfrequency of a toroidal resonator

All units are in the SI I'm doing my task from vacuum electronics - for the given klystron with a toroidal resonator[ Resonator: I have to find the $h$ parameter, that will satisfy given ...
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56 views

Leakage Inductance Coaxial Cable

I do not understand how a particular parasitic effect is model. I have read that on a coaxial cable there is a problem due to the fact that the external conductor's magnetic field crosses the air ...
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26 views

Flux and inductance in simple motor

This is the front view of a cylindrical motor of depth (or height) \$D\$. There are three windings: \$\alpha\$ (stator), \$\beta\$ (stator) and \$\gamma\$ (rotor): Considering the core to be of ...
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52 views

Is it possible to determine a low power isolation transformer maximum output current?

I have a transformer (no codes) 240vac to 12vac this is easy enough to determine but what about the maximum current? 1) I could load it until the voltage drops but to what exactly? 2) Is there any ...