# Questions tagged [inductor]

An inductor is a 2 terminal passive device that stores energy in a magnetic field.

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### Wireless power transfer circuit to attain ~5W of power on the receiving end

I am designing a WPT system to run a ws1812 based pixel chain. The ws2812 pixel chain runs on 5v and consumes 500-800ma of power, means 2.5w-4w. The system I made is not able to transfer adequate ...
34 views

### What material of a core put into the inductor would decrease the current?

Consider the $AC$ circuit: For various $U$ values set by the potentiometer, we have measured the current $I$ flowing through the circuit with and without core put inside the inductor $L$. As ...
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### How can I find mutual inductance and coupling coeffecient of coupled inductor knowing turns ratio, primary and seconday inductance?

Trying a simulation in PSIM I have turn ratios and primary and secondary inductances but don't know how to find mutual inductance and coupling coeffecient of coupled inductors
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### MIC4830 output voltage too low

I have built the typical applicaiton circuit from the MIC4830 datasheet. I have used the values for 0.4inch2 EL panel running at 900Hz (REL=0.369MOhm, RSW=321kOhm). The input voltage is 3.3V. My ...
93 views

### Is it possible to input DC PWM signal to a transformer?

I need to create a 100-120V 50mA output from a transformer. I do not need continuous steady output (no need DC 120V a 120V pulsating signal on output is enough.) N1/N2=1/12.2 secondary impedance ...
61 views

### Ringing seen when a zener diode is used with series diode as a snubber

I am trying to simulate the snubber circuit as given in "A zener with series diode"? there is some ringing seen at ouput. Here is LT spice ckt: Simulation result shows some ringing at ...
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### How can we calculate the force of attraction between a coil and a ferromagnetic object?

As the question states I’m trying to figure out how I can calculate the force of attraction between the magnetic field of a solenoid (coil) and a ferromagnetic object. I suppose we should somehow ...
53 views

### Pulse Transformer design problem: cant understand for sure whats the reason or irregular output waveform?

A ferrite core pulse transformer provided with 12V PWM signal (as primary winding input voltage) as shown in Fig-1, produces irregular output voltage across the secondary winding as shown in Fig-2. I ...
61 views

### Voltage across inductor immediately after the switch is closed (again)

The switch in this circuit has been open for a very long time (such that the circuit is in DC steady state condition). What is v2? The correct answer is v2 = 0 V, but how does that make sense? I ...
37 views

### Voltage across inductor immediately after the switch is closed

The contact switch in this circuit has been open for a very long time. The switch is connected to the circuit at time t=0. What is the voltage across the inductor (VL) immediately after the switch is ...
35 views

### What factors do I need to consider when selecting an inductor to use in a circuit with the MT3608?

I am trying to use the MT3608 chip to boost the power output of a 3.7V lipo battery from 3.7V to 5V, which will ultimately power an ATMEGA32U4 chip. Below is a picture of my circuit where I have ...
30 views

### Current when switching on with inductance. Role of Reactance?

When switching on the current through a coil it can be described as: $I(t) = \frac{U}{R} \cdot (1 - e^{(-x\cdot R/L)})$ For a sinusiodal current the complex resistance for a circuit with ...
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### Parallel RL Time Constant

So we have an RL DC circuit. If the inductor L1 has a high core permeability, there will be a high inductance and thus a long L/R time constant. So the circuit takes a long time to charge. Would ...
2k views

### What the purpose of a diode in parallel with a power switch

I've come across a circuit that has a diode in parallel with a power switch that's controlling a BLDC motor circuit. I was told that it's a flyback diode to prevent voltage spikes from an inductive ...
64 views

### Phase difference between resistor and inductor voltage in an RL AC circuit

In my textbook, it is given that $\mathcal {E} = -L\frac{\Delta I}{\Delta t}$. The graph of resistor voltage ($V_R$) and inductor voltage ($V_L$) in a series RL AC circuit is given similar to ...
46 views

### How low is “low DCR”?

I'm making a circuit with this PAM2401 IC to get 5V from my LiPo cell. Its datasheet calls for a low DCR inductor (on the "inductor selection" section). How much DCR can be counted as "low"? How much ...
71 views

### In a half-wave uncontrolled rectifier with RL load why does the voltage spike when current reaches 0A?

I understand that the inductor creates a negative voltage to oppose the change in current but I don't understand why the voltage spikes up instantly when the current reaches 0A.
48 views

### How does an inductor limit a voltage booster?

I’m making a voltage booster to boost li-ion voltages 3v-4.2v to 5v with high current and a small footprint. I’m using TI’s Webench tool to help. It suggest a 1uH inductor for a 12A load, but if I ...
77 views

### When checking for continuity between two points on a PCB, how do I know it's not going through an inductor?

When trying to debug a non-working circuit on a PCB, it can be difficult to trace the circuit flow visually, as described in the answer to this excellent and related question: How can I reverse ...
91 views

### Inductor : how to choose toroidal ferrite core material

I want a 2.2mH toroid inductor working at 200kHz switching frequency able to keep 2A saturated current. I found a ferrite core provider with these possibilities : - Core FT50-61 (12.7x7.15x4.9) with ...
96 views

### L- LPF in the power filtering

The supply for the device has relatively dirty 5V power. I was looking for the way to suppress the noise produced by the other modular components in the device, and was recommended this circuit as a ...
39 views

### Why is the inductor crossed by null current in this simple circuit problem?

I'm new to EE. While doing some exercises, I encountered a problem where I have the following sine wave circuit, where: e(t)=10cos(1000t)[V], a(t)=4sqrt(2)cos(1000t+pi/4)[A], C=1[mF], L=2[mH] The ...
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### Finding the waveform of current in a circuit

How do you find the waveform of current i1(t) in the following? Do I need to find the capacitive and inductive reactance then find the current i1(t)?
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### Inductors short at DC or does it have a voltage drop?

In previous courses, I remember we were told that capacitors act as an open circuit at DC and inductors act as a short circuit. I came across this video: https://www.youtube.com/watch?v=WR6qVvnDnI4 ...
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### Buck Converter - Inductor CCM and DCM

I have a doubt while selecting the inductor for a buck converter. TI App Note In This app note, in the abstract itself, they mention that this : This application report gives the formulas to ...
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### Struggling to get an amplified sine wave over a small inductor at low frequencies

I am building a power amplifier circuit to amplify a sine wave over an inductor from a function generator. However because the inductor is small and i'm running at a low frequency I am getting ...
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### Function Generator amplifier to drive resonance circuit help

I have a model resonance circuit that is excited with an auxiliary winding and I need to build an amplifier to be able to amplify the current from the function generator in order to drive the ...
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### Parasitic values of a laminated core inductor

How do I determine the parasitic values of an inductor? Since an inductor is made up of a series resistor with the inductor and a parasitic capacitor(parallel capacitor between turns and the core). My ...
45 views

### Simple circuit with an inductor in transient state

I have a problem with this circuit. I am supposed to calculate i(t) at the moment t=(0+). The parameters are:R=300Ωe(t)=12VL=0.1H Switch is closed at t=0 I know that current can't jump in the branch ...
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### LM2596T, Inductor selection

I'm trying to build a simple low voltage 0-12 adjustable PSU and the simplest way i could think of was using a LM2596T ADJ. In page 16 of the Datasheet there's a inductor selection selection guide, ...
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### Components for new designs [closed]

I'm replicating an open source pcba in order to learn how to build more complex PCBs and there is a part that is not recommended for new designs: https://www.mouser.com/ProductDetail/TDK/VLS252012ET-...
63 views

### Why does rectifier output is showing DC instead of pulsating DC

I am using below circuit for PFC. Before connecting coupled inductor's auxiliary output to the IC's Vcc, I wanted to make sure that it is coming properly or not. So when I probed the red dot in the ...
2k views

### How to create large inductors (1H) for audio use?

I am building a tube amplifier, and have decided to add a 5ch EQ to it. Historically, the ones used in guitar amplifiers were all passive RLC filter style systems, with large inductances of 0.5 - 2H ...
521 views

### Can the inductive kick be discharged without a freewheeling diode, in this example?

In literature we commonly see the use of a freewheel diode to protect the circuit against the inductive kick when the switch goes from closed to open (Fig 1). However, what would be the pros/cons of ...
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### Measuring parasitic capacitance of coil using an LCR meter

Would it possible to use an LCR meter (DE 5000) to measure the parasitic capacitance of an multi-tapped torid inductor? If this is possible how should i do this, to get the best results? Help is much ...
186 views

### Is my circuit solution correct?

simulate this circuit – Schematic created using CircuitLab I have to calculate the energy of the inductors magnetic field at t = 6 ms. I am given: E = 50 V, R1 = 10 Ω, R2 = 15 Ω, R3 = 20 Ω and ...
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### Inductor Voltage and Current Phase Delay on a DC Converter

We learn that inductors introduce phase delay between voltage and current for AC. On a DC-DC converter, such as boost, we have, at the inductor, a DC component superimposed with AC component with many ...
24 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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### How does one calculate the values of LF1&2 and C93?

I am learning about USB circuitry and one of the example schematics uses this lc low pass filter. I want to understand where these values came from? Thanks in advance. Link to article
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### 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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### Electrical RL circuit problem

So I am given u(t)=325sin(314t+90°)V i(t)=14.14sin(314t+30°)A I have to find the impedance Z∠θ, value for the resistor and inductor, inductive reactance Urms∠θ = 325/sqrt2 ∠90° Irms∠θ = 14.14/...
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### 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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### How to prevent voltage regulator board heating up and how thick traces should be?

Im designing a DC-DC voltage step down regulator based off of a switching regulator IC from texas instruments. I have designed the schematic and board accordingly and it should be able to supply 5A at ...
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### Winding an inductor questions

I am going to wind an tapped toroid inductor for a LCR circuit in an equalizer. I have calculated the number of turns I need for each winding. This is my first time winding an inductor so I need to ...
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### 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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### Inductor size versus tolerance

Say I’m planning to prototype some circuits (filters, oscillators, etc.) by soldering the component leads together in a “hairball” construction. If I use typical 10% or 20% tolerance inductors, how ...
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### What is the value of the opposing voltage created by the inductor?

Assume I've connected an inductor to a DC or AC source. The voltage across the inductor due to the source current would be L di/dt. But we know that the inductor induces/creates a voltage to oppose ...
163 views

### Buck Converter dies unpredictably upon connecting power

I made a PCB for an ESP32-based solenoid controller that is powered by a 24V DC Jack. I'm using an AP63205 Buck Converter to step that input down to 5V DC, and then a linear 3V3 LDO to power the ESP32....