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Thread: Practical Experiment in LRC circuits

  1. #11
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    Quote Originally Posted by jumper View Post
    I used multisims in college, it is great.

    Hundreds of discrete parts, IC chips, meters, supplies, etc.

    You download a free demo and get a student version for 42 dollars.

    Well worth it.

    http://www.ni.com/multisim/
    that looks like a good option
    The difference between genius and stupidity is that genius has its limits.

  2. #12
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    pspice is another software to simulate electrical circuits. you can download lite version for free:

    http://www.orcad.com/resources/download-orcad-lite

  3. #13
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    171201-1043 EST

    Whenever I reread post #1 I get the idea that Fishn sparky wants his students to work with real components and instruments.

    A more limited list:

    A range of stable resistors, and some resistors that change resistance with temperature (thermistors and incandescent bulbs).

    A Sq-D QO 15 A breaker.

    A 7.5 A Variac.

    A half horsepower capacitor run motor. This is RLC and some core saturation and counter EMF.

    A control transformer with two 240 V primary coils (parallel or series connection), two 120 V secondaries (again parallel or series), and about 200 to 500 VA. For transformer, inductance, and core saturation experiments.

    A range of polypropylene capacitors.

    A 100 ft roll of #14 with EGC. Outlets distributed along the run with various switchable breaks and/or high resistance joints. Purpose to show capacitive coupling to different loads (DVM vs low resistance meter). Estimate length of wire from main panel to an outlet. Show effect on motor starting from line impedance. How to troubleshoot problems by knowing something about the circuit.

    A 1500 W heater with no fan and continuous duty, 800 W if you can not find 1500.

    An old AB #2 motor starter. AC RL circuit with varying inductance.

    An 8ft magnetic ballast slimline fluorescent fixture. This is an inductor to generate large voltage transients on the line.

    An MOV transient voltage limiter.

    A Corcom 5 A line filter (LRC) to show reduction of broadcast band RF noise from the 8ft fluorescent.

    Your supply transformer with some knowledge about it, your distribution lines with some knowledge, a wire from the ground rod at the transformer to your test bench, this is just a long test lead, #18 or smaller is OK, and your main panel with measuring test points at the panel.

    .





  4. #14
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    Buy an old vacuum tube radio with variable capacitance tuning.

  5. #15
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    Jul 2013
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    Renton, WA
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    LTSpice is free also. One can also just put the equations into any spreadsheet and graph the results of varying requency, L, R, or C>

    Easiest to put together for an electrician is an old motor with the rotor pulled (L), a 50 uF motor run cap (C), and a 60 W light bulb (the R) .

    Hook all in series across 120
    vac 60 Hz.

    The motor core of an old 1/4 HP motor IIRC is around 50 mh. 50 uF and 70 mh resonate about 60 Hz.

    Light bulb somewhat dim to start, slowly put the motor rotor near the core, and inductance increases (or a big bar of iron)

    The light gets brighter as inductance increases to resonanace of L&C, then as you inser the rotor further the bulb will dim as the inductive reactance limits the current.

    If you have a 100 W or greater audio amp and signal generator, you can drive the LRC series at different frequencies and differenct LRC values and note how the light changes - the same as the current for PSPice or LTSpice or matlab will show.

  6. #16
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    Where is Fishn sparky? I would have expected some response by now.

    .

  7. #17
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    Quote Originally Posted by gar View Post
    171201-2052 EST

    Where is Fishn sparky? I would have expected some response by now.

    .
    Gone fish'n?

  8. #18
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    Quote Originally Posted by gadfly56 View Post
    Yikes! I have an old copy I got back in the 1990's floating around somewhere. It might have been $99 or $199 back then. Wish I could make it run on my Vista machine.
    Off topic somewhat, but load Virtual Box (free) and an old copy of Win98 or WinXP that you might have. That;s how I run my AutoCAD LT2002 on Win7 and Win10. (All licenses are legal)

  9. #19
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    Quote Originally Posted by GeorgeB View Post
    Off topic somewhat, but load Virtual Box (free) and an old copy of Win98 or WinXP that you might have. That;s how I run my AutoCAD LT2002 on Win7 and Win10. (All licenses are legal)
    As in post #8.

    Sent from my XT1585 using Tapatalk

  10. #20
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    Quote Originally Posted by GoldDigger View Post
    As in post #8.

    Sent from my XT1585 using Tapatalk
    I'll blame old age and senility; thanks for the reminder. It should last at least an hour<g>

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