An inductor is a 2 terminal passive device that stores energy in a magnetic field.
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517 views
Questions About Inductors
So I'm still new to electronics, and I've been taking a look at Boost Converters and such (just learning power supplies and the different types)...which got into explaining inductors. Needless to say ...
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4answers
1k views
Why do smaller loads require larger inductors in buck regulators?
The MC34063 Application Note lists the equation for calculating minimum inductor size as follows:
$$L_{min} = \frac{V_{in} - V_{sat} - V_{out}}{I_{pk}(switch)} t_{on}$$
But this implies that as ...
10
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3answers
2k views
Why does an inductor behave as a capacitor at high frequencies?
In truth, I've only been told this anecdotally by an instructor, but can someone explain the physics at play?
I have been told that if an inductor is driven at a high enough frequency, it will begin ...
10
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4answers
815 views
Can you store energy in an inductor and use it later?
My company uses supercaps to power the device if power is cut. I was wondering if you could do the same thing with an inductor. If you can't, why not?
10
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2answers
1k views
How do you choose an inductor for connecting separate ground planes?
On a board with separate analog and digital ground planes connected at one place, the connection is often made with an inductor. How is this inductor chosen? Obviously it has to be able to handle ...
9
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7answers
4k views
Inductor vs a capacitor
Hi am a Trainee electrician and pc hardware enthusiast. I was just wondering why a mixture of inductors and capacitors are used on motherboards? Why not just use capacitor? I thought the inductor ...
9
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1answer
1k views
What might be the cause of high pitch sound coming from a switching regulator circuit
We designed a switching regulator circuit using a 1.5Mhz, internal-switch, switching regulator (semtech.com/images/datasheet/sc185.pdf). Vin is 5V, Vout is 3V3. We have an input capacitor (47uf), an ...
7
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1answer
2k views
How important is self-resonant frequency for an inductor when used in a fast (~3MHz) buck SMPS?
I'm using the LM2734Z, a 3 MHz buck regulator. It's really fast which means it has a small inductor.
One of the things I'm wondering is how important is the self-resonant frequency of the inductor? ...
7
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1answer
239 views
Oops: shielded inductor very close to a crystal. Problem?
I've got a design that worked great on the two boards I hand assembled, but more than half of the boards from the local assembly shop are bad.
I've traced the most common failure mode to an unstable ...
7
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2answers
249 views
Transformers as Inductors (Weird Results)
If a transformer's primary and secondary are connected in series, then the total inductance of the result, is greater than the summation of each coil separately.
That is to say: \$ L_{total} > ...
6
votes
2answers
176 views
Inductor equivalent of capacitor's charge
Because inductors share similar equations in their charging/discharging cycles, I am wondering if inductors have something like charge.
Capacitors have capacitance and charge while an inductor has ...
6
votes
3answers
275 views
Buying/winding inductors
Are inductors usually hand-wound or bought pre-wound? For the former, how is the inductance measured? Is there some test instrument that can be used or is it done by measuring the length and radius ...
6
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1answer
189 views
Why don't wires have to be “covered” when making an inductor? [duplicate]
Possible Duplicate:
Why aren't solenoid/electromagnet windings insulated?
Looking at some pictures of inductors, such as this one:
The wires don't seem to be covered with a layer ...
6
votes
2answers
349 views
Can a Hartley Oscillator be built using Fixed Inductors?
I've been playing around with fundamental circuits (no professional EE background), and became interested in oscillators. I have been trying to build the Hartley oscillator as described here. The ...
6
votes
3answers
209 views
What's the best/easiest way to measure an unkown inductance without an RLC meter?
Is there a decent way to measure inductance accurately using an oscope and a function generator? The best method I can find is to build a tank circuit and sweep the frequency until the highest voltage ...
6
votes
2answers
210 views
Will placing inductors near each other have adverse effects?
I want to place two inductors next to each other on my PCB, will the fields interact in a way that would adversely affect each other?
If it's important they are 1mH each, with a 8V peak to peak, ...
5
votes
4answers
397 views
Is parallelling inductors a viable solution?
I am doing a space constrained board layout, in terms of surface area. So I found an inductor which is \$15\mbox{ }\mu H\$, \$2.3\mbox{ }A_{RMS}\$. I need about \$3.5\mbox{ }A_{RMS}\$, so I was ...
5
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2answers
3k views
Capacitors or Inductors?
So I know what they both do......but yet I don't know when you'd choose to use one over the other? There was a similar question on here, but the answer didn't really make sense to me (who is an ...
5
votes
3answers
213 views
Anyone know the purpose of these two inductors around a metallic ring?
So this link on ebay shows a power board that I have taken out from my microwave.
What is the purpose of these two wrapped around a metal ring? Also in general what is the purpose of this power board ...
5
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2answers
213 views
What inductor to use?
I'm working on a device utilizing Atmel's AT32UC3C microcontroller. The datasheet and design checklist documents provided by example schematics utilizing some type of RF/EMI inductor to isolate the ...
5
votes
1answer
928 views
How important is saturation current for an inductor?
I have a 15µH 1.6A inductor: http://uk.farnell.com/bourns/sdr0604-150yl/inductor-smd-15uh-1-6a/dp/1828004
The operating current is 1.3A, but the saturation current is 1.6A. What is the difference ...
5
votes
1answer
539 views
What does the “L” in inductance stand for?
"R" is resistor/resistance, and "C" is capacitor/capacitance, that makes sense. But where comes the "L" for inductor/inductance come from?
edit: Wikipedia says it's possibly in honor of Heinrich ...
5
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2answers
819 views
Shall I use a choke or a bead to filter analog power supply?
Often I have a 3.3V or 5V mixed-signal circuit with a microcontroller running in the 10 MHz range and some analog circuitry, e.g. audio or analog sensor signals, powered from a wall-wart style supply ...
5
votes
2answers
534 views
Choosing output filter inductors for switching power amplifiers
Class D PWM switching power amplifiers use an LC filter at the output to filter out the switching harmonics:
Other than the inductance value, what properties are important for this inductor? What ...
5
votes
3answers
1k views
Calculate the value of an inductor using an RL or LC circuit
Given an inductor of an unknown (though magnitude-estimatable) value, and a resistor of precisely known resistance, how can one calculate the inductance of the inductor?
Tools I have at my disposal:
...
5
votes
1answer
72 views
Cutting an RL Circuit
I was solving some problems with RL circuits today and a thought occurred to me that I couldn't answer... Say you have a Vsource Resistor and Inductor all nicely in a loop. You let the voltage source ...
4
votes
4answers
338 views
How do I select the correct inductor value for the following buck regulator?
First of all, I suck a bit at math, and I'm no electronics genius, so the stuff I do is for fun and for learning purposes...
I'm working on a buck converter circuit to convert my USB Vbus 5V to 3.3V. ...
4
votes
3answers
317 views
Creating a coupled inductor with two discrete inductors
Is it possible to create a coupled inductor (with high coupling coefficient) by just placing two inductors very close to each other on the PCB? (Even as far as placing them on top of each other.)
4
votes
2answers
272 views
Inductor purpose
I've just almost finished building the Single Side Arduino, but I'm missing one component: the 100uH inductor L1, right next to the pin 7 VCC of the chip. I am wondering what is the purpose of that ...
4
votes
2answers
929 views
How do I use a transformer as an inductor?
Lp: Self inductance of the primary winding.
Ls: Self inductance of the secondary winding.
Lm: Mutual inductance between the primary and secondary windings.
Assume that I need an iron core ...
4
votes
1answer
438 views
Data sheet inductance (R/A ?)
I have to implement a LC filter for a FT232H and its datas sheet (here) gives an example circuit (Fig. 6.1 VPLL- & VPHY-circuit). Strangely though a core-inductor is stated to be a 600R/0.5A.!
...
4
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2answers
246 views
Values of inductance - what is the “base” value?
I have a selection of salvaged inductors, and I don't (yet) have an inductance meter.
I would like to know what the inductances are, but I have a problem.
They are numbered with 3 digit numbers - I ...
4
votes
3answers
404 views
How to choose a inductor for a buck regulator circuit?
I am designing a buck-regulator circuit, with possibly the MAX16974 as the regulator. I have never done such a thing before, and actually not too much analog electronics at all. I got stuck at the ...
4
votes
1answer
169 views
LED driver circuit interfering with 555 timer?
Below is a circuit I put together that uses a 555 timer and an LED Driver:
But the strange thing I see is that the timer does not follow the 1.1*R*C equation. The led remains lit for much longer.
...
4
votes
2answers
222 views
What is “Two in hand” coil winding ? How does it affect the inductor?
Having to wind an inductor, I was advised to do it "Two in hand". I understand it means using two wires connected at both ends. Do I need the same amount of turns ? Is the inductance affected (same ...
4
votes
1answer
315 views
Inductive choke with bypass capacitors?
I've been looking at a few power input circuits and quite a few of them suggest an inductive choke with a large bypass capacitor followed by smaller bypass capacitors.
In theory this is what I ...
4
votes
1answer
400 views
Measuring ferrite core parameters
I have large amounts of inductors and transformers from power supplies or other undocumented sources. They are of course completely unmarked and I have no idea what kind of ferrite material they are ...
4
votes
3answers
124 views
How to Power a Tank Circuit with Mosfet without the Inductor Undesireably Triggering the Mosfet
BACKGROUND: I have this circuit that I asked about in a previous question:
Someone kindly explained that the problem I'm having with the circuit is that the mosfet is being triggered by negative ...
4
votes
1answer
114 views
DIY Inductor: Solve for number of turns without knowing the length?
I'm trying to wrap my own inductors (air coil) for an RF circuit that I am making and I am having a little trouble solving for the number of turns I need to reach the desired inductance.
...
3
votes
6answers
2k views
Why do buck (step-down) switching regulators require an inductor and diode?
So, I understand, at least at a basic level, the method of operation of switching converters, both buck and boost. What puzzles me, though, is why buck converters in particular aren't simpler.
Why ...
3
votes
3answers
932 views
Behavior of RLC circuit elements at t = 0
I'm wondering what are the behaviors of the inductor, L, and capacitor, C, at t = 0+
Please correct my understanding of the above circuit if I am wrong.
At t = 0, the capacitor acts like a wire. ...
3
votes
2answers
96 views
2 loads not working together on the same battery
One 12v car battery powers 2 loads. One load is 3.5A and the other is 100mA. The 100mA load is always on. When the 3.5A load gets switched on, scope readings show the amp draw momentarily dropping to ...
3
votes
6answers
693 views
how a phase delay occurs in capacitors/inductors with visual images
Capacitors provide a phase delay between the current and voltage. Current leads the voltage by 90 degree. I was taught these only with the equations. But I want visual intuition, what happens in the ...
3
votes
2answers
390 views
LC circuit: can it act as an “AC battery”?
I am curious about a resonant LC circuit. Assuming a perfect inductor and capacitor, would it be possible to tap off the energy in the oscillations to use it as a battery? Literally, it would be an AC ...
3
votes
4answers
2k views
Coupled inductor vs an actual transformer?
What is the difference between a coupled inductor and an actual transformer? The LT3757 datasheet mentions that I need a coupled inductor for the SEPIC to work
3
votes
1answer
58 views
Problem graphing inductor current-time
I am trying to graph the equation VbackEMF = L di/dt
When SW1 is off and has been off since negative infinity, I realize that there is no current in the system.
Now I imagine SW1 being pressed. ...
3
votes
2answers
432 views
PCB Trace inductance
I am planning to do a high current (200A+) PWM in a PCB and I am afraid the PCB traces inductances will be a huge problem...so I have some questions:
1- How may calculate the trace inductance?
2- As ...
3
votes
1answer
71 views
What is the most available hitemp superconductor for samples and study?
I could only find one named Amperium on the web, but not on the eBay or any little shops. It is very interesting material with conductivity 40 times better than copper. Is it possible to buy anywhere ...
3
votes
1answer
129 views
Peaking Inductance
Could anyone please explain the working of so called 'peaking inductors'? I know they are used to enhance the bandwidth but how do they do this?
3
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0answers
187 views
Joule Thief - operation and the 'supercharged' version
I've made a joule thief, and it works fairly well, but not as well as I would like.
It's powering a 3.2v LED from a 1.2v battery, but it's very dim. I'm hoping increasing the voltage from the JT ...
