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Uses of inductors

Discussion in 'General Electronics Discussion' started by Chickwolf, Apr 24, 2015.

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  1. Chickwolf

    Chickwolf

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    Jan 3, 2014
    Hello everyone. I have recently been studying inductors and all though I have covered what they do and how they do it, I have not been able to find very much on why they would need to be used within a circuit.

    Why would you need a component that creates a magnetic field within a circuit? What purpose do they serve and where would the common applications of inductors be?

    If I have been to vague please let me know and I can include more information. Thanks for anything in advance.
     
  2. Laplace

    Laplace

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    Apr 4, 2010
    A few common uses come to mind. Inductors are used to design passive filters for a wide range of frequencies. They are used in RF circuits to block high frequency signals while passing DC biasing current. They are used in voltage regulators where the inductive voltage 'kick' is used to boost the voltage.
     
  3. duke37

    duke37

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    Jan 9, 2011
    An inductor stores energy in a magnetic field, it follows that the current is reluctant to change as power has to be provided to do it. Thus, placing an inductance (choke) in a power supply line will tend to smooth the current.

    A capacitor stores energy in an electrostatic field depending on the voltage. By combining an inductor and a capacitor, a tuned circuit can be made. The energy is passed from inductor to capacitor and back again. This is similar to a pendulum where energy is passed from potential energy to kinetic energy and back again.
    Have you made a crystal set with a coil and capacitor and understand how it works?
     
    Arouse1973 likes this.
  4. Chickwolf

    Chickwolf

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    Jan 3, 2014
    I have heard of a capacitor and a inductor being used together in that way before but have never made a crystal set, if you wouldn't mind explaining that, that would be brilliant!
     
  5. Arouse1973

    Arouse1973 Adam

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    The big one would be motors, have a look at how these work.
    Adam
     
  6. Chickwolf

    Chickwolf

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    Jan 3, 2014
    Will defiantly look into that, thank you.
     
  7. Merlin3189

    Merlin3189

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    Aug 4, 2011
    1- You don't! Inductors are not used to create magnetic fields in circuitry. They do incidentally create fields, (often tiny, sometimes not) which we try to keep contained and hidden, but they are used for their circuit properties, not their magnetic field.
    2- Inductors have circuit properties that a) resist changes in current; b) cause phase difference between AC currents and voltages. This means they discriminate between different frequencies of AC (the frequency tells you haw fast the current is changing.) Inductors resist high frequencies.
    On the whole they are used mainly for radio frequencies, because inductors for audio frequencies need to be bigger and smaller capacitors can do the job.
    3- So they are used to select or block different frequencies in eg. audio filters and radio tuners. In combination with a capacitor (resists low frequencies) they produce a circuit tuned to one specific frequency. Loudspeakers often have inductors (and capacitors) to separate the current to the woofer from that for the tweeter.
    They are often put in power supply leads, to pass the low 50Hz mains, but block higher frequency interference (sometimes this is in the form of ferrite blocks clamped to the lead.) Electric motors (DC or universal) often have 2 small inductors wired in series with their leads to block any high frequency interference generated by brush sparks or fast switching (and a capacitor in parallel to short circuit them.)
     
    Last edited: Apr 25, 2015
    Chickwolf, Tha fios agaibh and davenn like this.
  8. davenn

    davenn Moderator

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    Sep 5, 2009
    nice one Merlin

    great description :)


    Dave
     
  9. Arouse1973

    Arouse1973 Adam

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    Dec 18, 2013
    Inductors have many other applications other than filters where I agree the magnetic field is usually quite small. However there are other circuits like oscillators, planar transformers and patch coils used for RFID and wireless power which without a large enough magnetic field they wouldn't work very well.
    Thanks
    Adam
     
    Last edited: Apr 25, 2015
  10. Chickwolf

    Chickwolf

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    Jan 3, 2014
    Thank you Merlin and Adam, you both have covered exactly what I wanted and more, many thanks!
     
  11. Arouse1973

    Arouse1973 Adam

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    Dec 18, 2013
    Your welcome.
    Adam
     
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