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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Flyback transformer parameters - Inductance

I am designing a power supply (flyback SMPS) with universal input (120 - 240 VAC) and 6 V @15 A output (90 W). For this purpose, I have shortlisted the pwm switcher NCP1219 - selected because it doesn'...
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Peak current of inrush limiting inductor?

I have this tricky question and I can't wrap my head around it. There is this inductor to limit the inrush current that will be charging up a capacitor. I'm questioning the design of it, but I don't ...
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Can a LC circuit generate frequencies in the Gigahertz range or higher?

For instance, if you took a bunch of off the shelf capacitors and arranged them in series and a bunch of inductors and arranged them in parallel, could you make the resonant frequency of the LC ...
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Skin effect reduce inductance

I have a question about the skin effect on inductors, I would like to know why the skin effect will reduce the inductance? You could see from the below figure, in the high frequency the inductance was ...
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Antenna inductance calculation (RFID applications, inductive coupling)

Inductance of various antenna coils of different shapes can be estimated. Some examples are: A circular coil with single turn. N turn multilayer circular coil. Spiral coil. N turn squae loop coil. ...
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What affect peak current in an RL load rectifier circuit?

so I'm running a half wave RL rectifier in simulink. I don't have much knowledge. May I know what affect the peak current in the half wave rectifier circuit (the theory behind it) and how do I ...
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Measuring time-varying inductances

I am using a circuit based on an LC tank and Arduino that is used to measure inductances. The amplitude for the current pulse is of 40 mA, approximately the current that an Arduino pin gives at 5V. ...
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Typical inductance of power (probably wound) resistor

I need a big resistor to dump reactive energy to. But I need it 'fast' since otherwise the input TVS will overload. The situation: parasitic inductance of wiring makes the whole circuit substantially ...
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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.
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How to simulate a transformer in LTSpice with custom turns ratio and inductivities?

LTSpice calculates the turns ratio of a transformer with SQRT(Lp/Ls). This is however only true if both windings have the same geometry. I have an air-core transformer with an Lp of 10μH, an Ls of ...
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What does negative capacitance mean?

I see negative capacitance measuring electrolytic capacitor at high frequencies (40kHz). How should I interpret that? The device is LCR Meter Hantek 1832C. I failed to find anything about that in the ...
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Self inductance vs loop area of inductance. How to combine them/which to pick in which case?

When it comes to inductance in circuits, it is a rule of thumb to minimize the loop area. This implies a return path (i.e. two wires). There is also self inductance of a single wire. I am not sure how ...
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Blynk Device (ESP32) disconnects when I turn off my N-Channel MOSFET for my RGBW LED strip

I have a lamp that that consists of a strip of RGBW LED's. I'm using an ESP32 to control the LED's (since they are programmable), and I am controlling the actual LED's through an app called Blynk. I ...
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Should I place vias for each parallel decoupling capacitor? [duplicate]

First of all, excuse my potentially poor understanding of electricity, I'm a low level programmer and I'm doing my first PCB (4 layer-stackup - signal/gnd/power/signal). I was placing these two ...
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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 ...
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Is there any simple way to calculate the turns per volt and required core area for a high frequency transformer?

I was trying to find some simple equations for designing a high-frequency transformer. The operating frequency will be 10-15 kHz. I searched many sites and didn't find any simple equation to calculate ...
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Automatic metal detector using an Arduino

I did a project on automated metal detector, but I am not clear on the circuit. I built the circuit connecting a resistor to pin A4 on the Arduino, and a diode capacitor setup in series too. I don't ...
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Coaxial Cable with signal applied to shield and center conductor grounded

The standard way to drive a signal through a coaxial cable is to have the shield grounded, and a single-ended signal applied to the center conductor. (Throughout, I will assume that \$R_{term}\$ and \...
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2 votes
4 answers
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What happens to parasitic capacitance and inductance in a superconductor?

Do the parasitics also become [more] ideal? Are all changes solely due to the perfect conduction? If not, how are the parasitics affected? Such basic information seems necessary to engineer any ...
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Inductive coupling using earth ground instead of negative terminal in a power supply

I was a TA for an introductory EE class when I heard this comment. We would help students through basic lab exercises. Helping them troubleshoot, the students would sometimes use the ground connection ...
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4 answers
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What on a digital PCB could affect the boost converter output?

I have designed a fixed 12 volt boost converter module and it works. I tried to implement the same booster on my project PCB, but with all same components it can't provide 12 volts when it gets any ...
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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 ...
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Ethernet Magnetics, Discrete vs Integrated: Inductance Value

I recently made a change to an EtherCAT-over-Ethernet design, where I moved from using an RJ45 with integrated magnetics, to a low profile connector with discrete magnetics, due to size constraints. ...
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What is the difference between ESR and DCR?

I am measuring the inductance of a large coil using an LCR meter. I am using the series equivalent measurement mode at 100 Hz. Why does the LCR meter show that the ESR is 656 Ohm and why does my ...
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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 ...
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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) (...
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6 votes
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Why so much space around these toroid windings?

I have recently noticed some toroids wound with what I consider to be huge space left over, and I am asking if there is any good reason to do this. (or even an acceptable reason would do). My thoughts ...
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Sine wave signal lagging; potentiometer has inductance? [closed]

my sine wave at the midpoint of potentiometer is lagging by 74 degree when comparing to the input, and my potentiometer is 500Kohm. Is there a low inductance potentiometer? I do not know how to pick a ...
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Transformer core inductor: E vs EI shape inductance relation

I have an EI laminated iron core inductor (with gap) of 32mH of inductance with the coil winded on the central leg. I need to reduce the inductance using the same component without touching the ...
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How do I calculate the inductance value of an inductor in an LR circuit given input voltage, resistance and dI/dT at the moment a switch is closed?

I have been working at this problem for a while. simulate this circuit – Schematic created using CircuitLab Given the values of V1 and R1, plus the fact that at the instant SW1 is closed the ...
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How to calculate the voltage drop across a load connected in series to the secondary coil of a transformer

I need to know how to calculate the voltage drop across a load connected in series to the secondary coil of a transformer. I know the resistance (Rs) and inductance (Ls) of the secondary coil (and ...
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3 answers
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How to guarantee steady state conditions on boost converter

I am teaching myself about boost converters, and I understand the operating principles- to a point. Specifically, I understand what happens to the conductor during the switch-closed portion of the ...
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2 answers
295 views

How to model a 10 m twisted pair wire

I would like to model a 10 meter twisted pair wire from a CAT 6 ethernet cable. I'm trying this out so that I can know if my driver circuit is capable of sending a signal that is still acceptable for ...
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Is this explanation of a common-mode choke correct?

I am trying to understand how common-mode chokes work. I get the basic concept: the signal lines are joined by a transformer, such that each line will aid or impede current in the other. But I am hazy ...
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Why are inverter bus bars made overlapping?

A lot of literature on bus bar design suggests that bus bars should be made to overlap or have equal area such as this. The reason they mention is the total stray inductance falls due to increase in ...
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10 votes
3 answers
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Why is the inductor's voltage not specified in the datasheet?

I looked through a few inductors' datasheets and in none of them is the maximum voltage specified. Even Mouser does not let you filter inductors by voltage. Why is that? Is inductor voltage "not ...
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Transformer Design I do not understand how to adjust AL when adding an air gap

I am trying to follow: http://ludens.cl/Electron/Magnet.html Specifically this section and how AL is adapted when an air gap is added (Initial AL is 6µH): Let's see what happens if we add an air gap ...
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Why does inductor core saturation depend on the temperature?

For example at room temperature (20ºC) the saturation current is 450mA and with 100ºC the saturation current is 350mA. What causes this? (Edit) The higher inductance with higher temperatures and lower ...
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Does the current or voltage switch when an inductance goes from being a load to a source?

When first S1 is closed to charge the coil the voltage UL and current IL are inline and positive. When the switch S2 closes and S1 opens, does the current or voltage switch direction?
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Reactive power and eletro-mechanical analogy

Regarding this question, I will try to use the analogy of the differential equations $$F = m\frac{dv}{dt}$$ and $$V = L\frac{dI}{dt}$$ and $$w = \int Fv dt$$ with $$w = \int VI dt$$ to figure out the ...
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4 answers
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Is the association of useful work to active power a convention?

I know that there are many questions about reactive power. What I am trying to understand is what is sometimes called useful work associated to active power, compared to no useful work for reactive ...
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1 vote
2 answers
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Calculating the parasitic inductance of a capacitor

I have looked at this article, but it does not answer my question. My question is: how would you go about measuring and/or calculating mathematically the self-parasitic inductance of a capacitor if I ...
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Why does switching OFF heavy electric loads cause a surge in voltage?

A voltage surge is a higher-than-normal voltage that temporarily exists on one or more power lines. Voltage surges are normally caused by the switching OFF of heavy electric loads. I know that most of ...
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Impedance of PCB track

I was wondering if PCB tracks have a typical complex impedance? This is for a signal of frequency 1khz.
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Mutual Inductance Practical Explanation

I can't understand why the Mutual Inductance is measured in Henry. The self inductance of a coil is the abillity that has a coil to create a magnetic field that produses a voltage on itself so to ...
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Is this video fake? I thought Tesla coils only worked on AC

This video shows a 9-volt battery is connected to a wire as a primary. The first reason I think this is fake is that he is powering a Tesla coil with 10 volts. The second reason is that Tesla coils ...
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What is a good loop probe to use for non contact measurements at 13.56MHz?

I have a receiving antenna (9 turn spiral, 1cm in diameter) that I would like to measure (inductance) wirelessly at 13.56MHz. While looking through application notes from ST and NXP semiconductors, I ...
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1 vote
1 answer
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Calculate inductance and capacitance of a double layer antenna (RFID)

I want to design an antenna that will work with RFID NFC chip NHS3152. The NHS3152 IC specs are: IC capacitance at precise measurement conditions For this particular IC, there is a demoboard. Since I ...
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How frequency-dependent is an air inductance?

For a winding on a magnetic material, the value of the inductance is greatly impacted and is also frequency-dependent given the behavior of the magnetic material according to frequency. My question is,...
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Internal Inductance of MOSFET

Datasheets sometimes define an internal inductance (example here). From what I've read, internal inductance is defined as the inductance of the wire's flux acting on its internal cross sectional area. ...
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