Type: Posts; User: dick_freebird

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  1. Closed: Re: Are there relays made for inductive loads

    You need to look carefully at the guts of a SSR. SCR / Triac
    types behave badly with inductive loads (though I have used
    phase-cut dimmers to run series-wound motor tools, neither
    the dimmer nor...
  2. Replies

    Closed: Re: Make component in LTspice

    I'd take the LED .model and scale Vf and Rs by *N (string #),
    as a start. Same for the (Schottky?) diode string. Then one
    diode of each, referring to the customized models, done.
  3. Closed: Re: heat shrink tubing over heat shrink tubing

    I've done this many times for the same reasons. You might
    look at alternatives such as automotive wire-loom and strain
    reliefs; you do not want your soldered lug connectors to be
    the mechanical...
  4. Closed: Re: Are there relays made for inductive loads

    The desired product is unclear to me.

    AC-coil relays might be a bit funny operated at 140Hz but
    it's not really said, what's the coil drive and what's the
    switched source and load.

  5. Replies

    Closed: Re: gate connection using poly vs metal

    There are good reasons for and against, as the engineer
    the value judgment is up to you.

    For example maybe it's better to route poly in a standard
    cell logic library, than "bake in" metal2...
  6. Closed: Re: Adding a pulsed switch to a dc voltage source in cadence library

    You could consider using poly sources (vcvs) to create Vdd and the "switching input", a (say) 0-1V ramp at one terminal pair for the time varying aspect, a V=3.3 source multipled by the ramp is your...
  7. Replies

    Closed: Re: gate connection using poly vs metal

    There will be a "master" and N "slaves" in the current mirror
    rack and you want to pay attention to where the reference
    current flows. For example if you push the current in at the
    left end of a...
  8. Closed: Re: Searcking for an IC with fast rise time low frequency

    Might get a "clock in a can" oscillator (fixed or VCO) with
    an HCMOS output, and use the fastest AC series gate
    you can find to sharpen up the drive edges. With good
    layout and maybe HC drives...
  9. Closed: Re: Generating more EMI due to BLDC motor

    Your 63MHz might be winding SRF or some other aspect of
    the harness and electromechanical assembly ringing. Might
    be worth connecting some other load and see if the frequency
    moves (say, another...
  10. Closed: Re: using a crankshaft position sensor to implement electronic ignition

    The modern-ish cars I've worked on have CKP (crankshaft position)
    sensors but this gives you two possibilities for trigger, 0 and 180
    camshaft degrees from where you want. A camshaft sensor ...
  11. Closed: Re: Gm of transistor in hspice when it is called XM

    I have no idea what "xl7" is or is meant to do, but I would
    be looking for something like


    in simulator-appropriate syntax for gm, and plot...
  12. Closed: Re: Misconceptions and flaws noticed by the more educated...


    2) Ohm's law wrongly taught as R=E/I. R=E/I is the definition of resistance, not Ohm's law. A resistance follows Ohm's law if its value is constant over a reasonable...
  13. Closed: Re: Gm of transistor in hspice when it is called XM

    There will me something like XM8^M1 as a device at the bottom
    of it all, which can be probed in the usual way as long as you
    "spell its name right". If you're using a GUI schematic driven
  14. [SOLVED]Closed: Re: can flux from switching inductors cause interference

    We did not like ground planes under the SW node because
    it couples all that trash right into the ground, messes up
    current sense and other ground (which ground?) referred
    signals etc. The SW...
  15. [SOLVED]Closed: Re: can flux from switching inductors cause interference

    Circular sweep trimpots include a "free 3/4 turn inductor
    in every box".

    You could check the hypothesis easily enough by soldering
    in a tight pair of chip resistors of appropriate (to the trim-...
  16. Closed: Re: Misconceptions and flaws noticed by the more educated...

    The larger problem may be in expecting textbooks to teach
    everything. Especially ones written by professors who have
    avoided practical hard-knocks lessons in favor of formulae.

    We are awash in...
  17. Replies

    Closed: Re: Improving efficiency

    I have found it most helpful to concentrate on the "elements
    of inefficiency". Efficiency of the assembly is your report card.
    Inefficiencies are what you quantify and drive down one by
    one, as...
  18. [SOLVED]Closed: Re: can flux from switching inductors cause interference

    Component "failure" is a pretty remote possibility but circuit
    misbehavior is commonplace.

    You can get charge pumping across any junction if there is
    AC activity on the pins. This is a known...
  19. Replies

    Closed: Re: filling empty space in layout

    I like to fill with decoupling capacitors, which I make by
    stacking metal layers over (say) 20/5 multifinger MOSFETs
    for a parallel thin ox, thick ox plate set. This can be positive
    for density...
  20. Closed: Re: How can I generate Sine wave from any periodic waveform that has low frequency?

    Could use a PLL to generate a 2^N*Fin clock, roll a counter
    through a sine wave lookup ROM/PROM/EPROM and use that
    data to control a second "on time" counter (load) for PWM
    creating a sine at the...
  21. Closed: Re: Using MOSFET as load for voltage regulator?

    You can go a couple of ways but I have come to prefer
    a bank of logic level power MOSFETs each with a binary
    weighted "burden resistor" and logic control (DIP switch,
    USB-DIO, whatever your data...
  22. Closed: Re: Poly dummy instead of poly transistor

    Depends how good you want the dummy to be, and what
    aspects of process lithography stand to affect device

    If you don't know, in detail (and even "inside foundry" guys
    rarely do) then...
  23. Replies

    Closed: Re: quadrature ring oscillator 5GHz

    Easiest way to a quadrature oscillator is 4 stages of fully
    differential gain, with three of them cross-connected (so
    as to be inverting) and one straight (noninverting).

    But you need to think...
  24. Closed: Re: Attract fish by sound, light or anything else

    Finding fish and attracting fish are two different problems
    (although attracting them ought to make them right easy
    to find).

    Shrimp will come to a light. Not sure about fish.

    I've read...
  25. Replies

    Closed: Re: voltage controlled oscilators

    Many VCOs have only one stage. I'm guessing you are
    talking about ring oscillators and/or DLLs.

    At very low stage counts, the edges of a RO will be more
    "leisurely" and prone to translate...
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