Recent content by Kerrowman

  1. Kerrowman

    Measuring an NST Output

    Here is how I think adding diodes can be useful to prevent a short detection, whatever way the centre tap is configured, and without a half-wave rectified result. In each half of the output cycle, one or other of the diodes is in forward bias - isn't it?
  2. Kerrowman

    Measuring an NST Output

    Thanks for the detailed reply. In a previously built divider I had a common ground and sockets for + and - on the HV and LV sides but this ‘new’ design doesn’t. Instead I think when necessary he uses a lead to connect the LV output neg to the HV source neg/ground. That would get round the stray...
  3. Kerrowman

    Measuring an NST Output

    Im not new to working with electricity and have researched HV back pulses for the last 6 years and published it all. I’m just newer to working with a NST and can’t get the info I would like from the manufacturer.
  4. Kerrowman

    Measuring an NST Output

    I'm planning to measure the HV output waveform from an NST using a 1000:1 potential divider, which is yet to be built, and I have a few queries about the measurement setup. I have included a diagram of the proposed design and arrangement and where the small NST has a stated output of 1.5kV RMS...
  5. Kerrowman

    LC tank circuit with HV driver

    Not quite. When I replace the spark gap with a 1kV GDT, the system does not function at all. I had hoped that the GDT would result in more consistent 'ringing' of the tank circuit. Any ideas why using it appears to short out the tank circuit?
  6. Kerrowman

    LC tank circuit with HV driver

    The 48MHz I have shown to be from the wide spectrum output caused by the spark gap. The LC resonance is clearly visible at around 950kHz as expected. The unresolved issue is why when using a GDT (1kV), the circuit stops resonating.
  7. Kerrowman

    LC tank circuit with HV driver

    I think these were the ones. I have sorted most of the issues except why using a GDT instead of a spark gap seems to stop the resonance occurring. The scope is basically a flat line.
  8. Kerrowman

    LC tank circuit with HV driver

    Hi there, I'm exploring resonance in LC tank circuits at radio frequencies and have a query about my observations. In the first picture, I have a 6𝜇H coil and a 4.8nF cap in parallel, and I have measured the f(sr) using the setup shown in the attached. The result, according to the scope, is...
  9. Kerrowman

    Capacitor Charging with HV Pulses

    Sure, that's very kind of you. I will compress the .asc and the .mdl file together. Can I place the zip file on my G-Drive and post a link here? Will that get through? Sending separate files to you.
  10. Kerrowman

    Capacitor Charging with HV Pulses

    Thanks for that. The video is also useful as I have the Mac version of Spice so can follow him fine. 😊 However, when I follow his steps I am not allowed more than one IC so when just using one, and the expression 'tran 0 1m', I get another error saying 'missing nodes'. I'm not sure how to...
  11. Kerrowman

    Capacitor Charging with HV Pulses

    Hi Harry, I’m sure it’s very good and interesting but it deals with far more than I need to address linked to my research studies. I simply don’t have the time anyway with publication deadlines. Is there no guidance you can offer on the specific question as to where I would probe the sim...
  12. Kerrowman

    Capacitor Charging with HV Pulses

    Hi Harry,   I have obtained a fairly good Spice model now, as per the diagram, that works quite well. It is not especially accurate in calculating efficiency, since the model does not include skin effects and other parasitic inductance and capacitance values. I have attached some calculations...
  13. Kerrowman

    Capacitor Charging with HV Pulses

    Actually, I now understand that all the discharge energy will in fact be dissipated in the electronic load, so there is no 50% here. So my question changes to: assuming the sim components are accurate, how can one use the sim data to derive the efficiency of the delivery of energy to the...
  14. Kerrowman

    Capacitor Charging with HV Pulses

    Hi Harry, Thank you, that is very interesting. The VDS (a comparator and high-sided P-FET) is just a way to discharge the capacitor so it can repeat its charging and show multiple traces on the scope from which I can take measurements and do calculations. Is it possible to determine the energy...
  15. Kerrowman

    Capacitor Charging with HV Pulses

    Hi Harry, I am reliably informed that the circuit I posted is pretty much the same as a Boost Converter (with my added VDS) where the transfer of energy on charging is close to 100% due to the way the energy is stored in the coil’s magnetic field before being transferred with high efficiency to...
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