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Type: Posts; User: treez

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  1. Closed: Re: Which transformers can pass approvals testing rergarding isolation voltage testin

    5 and 6 are primary bias.
    I am not sure if their were scorch marks, they just told us we failed.
    If it goes over 3mA when 3.5kv is applied for one minute then its a fail.....

    - - - Updated - -...
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    Closed: Any ideas about this 400V, 1A Bench PSU?

    Hello,
    Does anyone have a schematic for this HSPY-400-01 Bench power supply? (400V, 1A)
    ...
  3. Closed: Re: Which transformers can pass approvals testing rergarding isolation voltage testin

    Thanks, the pinout is as attached. There was tubing used yes.
    As you know, There is easily 8mm betweeen primary pins and secondary pins.


    Thanks, as you know, there is no need for slotting as...
  4. Closed: Re: Which transformers can pass approvals testing rergarding isolation voltage testin

    Thanks, its re-inforced insulation.
  5. Closed: Re: Which transformers can pass approvals testing rergarding isolation voltage testin

    Yes, and as discussed, its primary, bias and secondary with TIW.
    The primary bias coil is the last to be wound on it, (so its the top layer)


    The creepage or clearance from secondary termination...
  6. Closed: Re: Which transformers can pass approvals testing rergarding isolation voltage testin

    TEX-ELZ Triple insulated wire by Furukawa is surely rated to 3.5kv for one minute?

    https://www.furukawa.co.jp/tex-e/en/product/texe_feature.html
    There is easily >8mm of spacing between primary...
  7. Closed: Which transformers can pass approvals testing rergarding isolation voltage testing?

    Hello,
    Our contractor designed a 10W, 24Vout, offline Flyback SMPS for 240VAC input. He had a split primary and a bias coil on the primary side, both wound with enamelled copper wire. He also had a...
  8. Closed: Protecting the inputs of HV7802 current monitor from damage due to inrush current

    Page 4 of the HV7802 datasheet (RHS of page, 2nd paragraph down), states that adding a resistor into the LOAD pin gives protection for the HV7802.
    It states that there is a bias current at the...
  9. Closed: Re: Film capacitor failed in flyback smps at high temperature?

    Thanks, i wonder how high the temp has to be, and for how long, with the cap of the top post to get this failure?
    Its datasheet doesnt tell of this.
  10. Closed: Film capacitor failed in flyback smps at high temperature?

    Hello,
    We are using the ECW-FD2J185 (1.8uf, 630v) film capacitor in our offline flyback smps, 240vac input.
    It is for 24v, 10w output.

    We sent it off for extreme temperature testing and it...
  11. Closed: Re: Input stage to 24W buckboost LED driver is high in component count.

    Thanks, yes if we cant find low enough rdson fets (which we probably wont at the high vds) then we will use a standard diode.....
  12. Closed: Input stage to 24W buckboost LED driver is high in component count.

    Hi ,
    The attached is an LTspice sim and pdf schem of the input stage to a 8-136vdc input , 24w buckboost led driver.
    The Vin may also go up to 385VDC for one second. (I presume this is some kind...
  13. Closed: Re: Supply 5V, 5mA from the 240VAC mains without SMPS

    Thanks asdf44, your RHS example above is absolutely great. It looks so good that id like to simulate it to see it going.,...but ltspice doent do dep mode fets.
    Though one point is that depletion...
  14. Closed: Reverse polarity protection with FET is somewhat blighted by CDG capacitance

    Hi,
    It is necessary to provide reverse polarity protection for a 24W Buckboost LED driver with Vin = 8 to 136VDC. (when vin <18v, then power can be reduced to 2W).
    I find that the diode D3 is...
  15. Closed: Why should a solder joint be less than 110degc?

    https://www.vishay.com/docs/28870/pulseloadsmdlimit.pdf
    Page 1 of the above says a solder joint should not be 110deg C or more..why?
    I looked on google etc but nothing....110degc is well below...
  16. Closed: Re: [moved] Why Zener getting heat at no load in Capacitor power supply arrangement..

    https://www.edaboard.com/showthread.php?386831-Supply-5V-5mA-from-the-240VAC-mains-without-SMPS
    the above is also about cap droppers...there is a simulation there that you can adopt for your use....
  17. Closed: Re: Why use diff mode inductors rated for 6A(rms) when Input current is only 833mA(rm

    Thanks, but this was just a power supply for the led lighting in the aircraft....though maybe that could be important i admit.

    - - - Updated - - -

    I must admit i read DO140, the avionics...
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    Closed: Re: SMPS Flyback Transformer Construction

    https://ac-dc.power.com/design-support/product-documents/application-notes/an-18-topswitch-flyback-transformer/
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    Closed: Re: Limit Current Maintain Voltage PSU output

    perhaps you need a current monitor and a microcontroller, so that the micro can allow the overcurrent to be drawn for just long enough for you to make your observations.....your power supply will...
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    Closed: 60W offline flyback PCB suffers burning

    Hi,
    Our contractor has done a prototype 60W offline single stage, PFC’d Flyback (240VAC).
    The primary FET is a metal tabbed TO220 and is directly screwed to an aluminium heatsink (no insulating...
  21. Closed: Re: Gerbers and drills offset from one another...cant view properly in GC prevue

    Thanks, out by a factor of 2.54 suggests drill is in imperial and gerbers are in metric.
    We have no control over this...our external pcb layout guy sends us the gerbers and we are stuck with...
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    Closed: Re: PCB flexion and cracking of SMD capacitors

    Thanks for this
    https://www.digikey.com/Site/Global/Layouts/DownloadPdf.ashx?pdfUrl=9A23B3687C14472482403C3540CC7267
    ...figure 1 of this suggests to me that we would be best off screweing in our...
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    Closed: PCB flexion and cracking of SMD capacitors

    Hi,
    For the following nine SMD ceramic capacitors on a PCB, which capacitor would you say is most likely to suffer cracking?
    I am talking about cracking due to board flexion. This board gets...
  24. Closed: Re: Lumens/Watt in LEDs when forward current is very low.?

    Thanks, i mean for current from 0 to 50mA in the above mentioned example (page 10, top graph)
  25. Closed: Lumens/Watt in LEDs when forward current is very low.?

    Page 10, top graph, (datasheet below)…what happens to the graph below 50mA?....is it just like a continuation of the same general shallow curvature?
    The graph concerned shows luminous flux vs...
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