Search:

Type: Posts; User: Easy peasy

Page 1 of 20 1 2 3 4

Search: Search took 0.09 seconds.

  1. Closed: Re: Generation of 4 Phase Shifted clock Signals

    CD4015B should do it (?) 4 stage shift register - dual -

    - - - Updated - - -

    sorry - I missed post #7 - at 2.5MHz it is futile to use discretes because of the delays introduced ...
  2. [SOLVED]Closed: Re: Calculate Capacitance Value from Smith Chart

    respectfully - even if there is loads of resistance as there is here - 50 ohm in fact - the Smith chart tells you the reactive impedance AND the resistive impedance hence 50-j77 ohm ...
  3. Replies
    11
    Views
    260

    Closed: Re: Buck converter vs buck-boost converter

    respectfully - you not bucking or boosting from input to output... a common ground is also often assumed which this ckt cannot supply
  4. Replies
    19
    Views
    403

    [SOLVED]Closed: Re: Wiring of DC fans in Series

    a cheap buck converter to give to 12V for the fans is looking better and better ...
  5. Replies
    11
    Views
    260

    Closed: Re: Buck converter vs buck-boost converter

    you may get the same total losses as only one fet to control and one o/p diode - plus far easier control - less time to build and get going ...
  6. Replies
    19
    Views
    403

    [SOLVED]Closed: Re: Wiring of DC fans in Series

    Q4 is not needed - Q3 will dissipate, Ifan * 15V so be careful there ...
  7. Closed: Re: Mains leaking currents causing problems in my house

    A PC psu should be designed to at least 2.5kV ac phase to o/p's if not it is a very bad PC to own

    a dish washer could be run thru an isolation Tx - but an electric cooker would...
  8. [SOLVED]Closed: Re: Calculate Capacitance Value from Smith Chart

    he reactive part is 77.16 ohms, this is the sum of the Xc & XL, at 205MHz it is basically all capacitive so yes = Xc
  9. Replies
    11
    Views
    260

    Closed: Re: Buck converter vs buck-boost converter

    A flyback is also a buck-boost ( the original in fact )

    - - - Updated - - -

    as is a Sepic
  10. Replies
    19
    Views
    403

    [SOLVED]Closed: Re: Wiring of DC fans in Series

    R's are fine - but extra power draw / loss and no guarantee of sharing at power up where fans can and do draw more than 5x the run current - and its pretty pulsed too...!

    - - - Updated - -...
  11. [SOLVED]Closed: Re: Calculate Capacitance Value from Smith Chart

    the Smith chart is for a specific 10pF cap, that is clue #1, it is not explicitly shown on the Smith chart, but the 77 ohm at 205MHz gives you 10pF, presumably at very high freq the series L ...
  12. Closed: Re: Mains leaking currents causing problems in my house

    You could go around cutting out all the Y caps ( RFI caps that go from phase & neutral to "earth" ) inside the appliances that have them - this should stop you getting a boot off your PC - ...
  13. Replies
    19
    Views
    403

    [SOLVED]Closed: Re: Wiring of DC fans in Series

    a 5W 16V zener across each fan will be the way to go, else a buck converter to 15V to run both of them in //.
  14. Closed: Re: Generation of 4 Phase Shifted clock Signals

    CMOS gate parts can do this easily @ 2.5MHZ look up the CD4000 series - there should be a shift register type part that will do it in 16 or 14 pins ...
  15. Replies
    11
    Views
    260

    Closed: Re: Buck converter vs buck-boost converter

    boost converter usually has low side drive to the fet which is easier, buck converter needs a level shift driver or a P channel fet - more parts will affect efficiency - but either can...
  16. [SOLVED]Closed: Re: Calculate Capacitance Value from Smith Chart

    The smith chart for that cap shows you that at 205MHz it is 10pF ( 77 ohm ) and 50 ohm resistive ...
  17. Replies
    3
    Views
    172

    Closed: Re: Filter Cutoff Frequency

    the noise flows from right to left - ideally the CM caps need to be on the LHS ( left had side ) in order to get a CM LC filter - this can be undone if the primary mosfets are heatsunk to...
  18. Replies
    10
    Views
    611

    Closed: Re: Bridge diode thermal problem

    bigger caps = shorter current pulse = higher rms current draw = more heating in diodes and wires ...

    45V, 10A schottky a good idea if pk volts out of Tx are < 35V ... 5W zener...
  19. Closed: Re: How to calculate transformer winding losses

    Is a round-a-bout way of saying there are proximity losses in the copper wdgs associated with the windings - these losses are lower for higher coupling factor ( lower leakage )

    and are...
  20. Replies
    3
    Views
    166

    Closed: Re: Maintaining supply voltage on load

    better to have a pwm buck converter drive the heater from the batteries such that there are no sudden changes in the battery voltage

    OR: drive the fet with a 470k resistor such that it turns...
  21. Closed: Re: Closed-loop Stable for Negative Phase Margin?

    The bode blot requires that you consider the 1st crossing of the gain plot, not any later ones, if there is phase margin at the 1st crossing, it will be stable, later crossings can be ignored...
  22. Replies
    11
    Views
    537

    Closed: Re: Photocoupler Saturation?

    there is a fair chance your led will eventually die if subjected to unlimited current flow pulses ...

    opto's turn off slowly due to carriers stuck in the base region of the o/p xtor - faster ...
  23. Replies
    3
    Views
    276

    Closed: Re: H-bridge gate signal problem

    welcome to the world of RFI ...
  24. Closed: Re: Film capacitor failed in flyback smps at high temperature?

    hi temp = expansion of either type of cap = end termination failure = cap goes low capacitance ....
  25. Replies
    13
    Views
    1,045

    [SOLVED]Closed: Re: HEI primary current duration

    certainly you will need soft turn off of the igbt to avoid a spark - if you are calculating dwell periods based on current rpm -
Results 1 to 25 of 500
Page 1 of 20 1 2 3 4