Vacuum Fluorescent Display (VSD) and a Z280 Microprocessor

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  • Опубликовано: 18 ноя 2024

Комментарии • 5

  • @clarefreeman3909
    @clarefreeman3909 Месяц назад

    Thanks for another great video Chris very nice construction

    • @lishaton
      @lishaton  Месяц назад

      Thank you Clare!

  • @Enigma758
    @Enigma758 24 дня назад

    Hi, shouldn't there be current limiting resistors on the PNP collectors?

    • @lishaton
      @lishaton  23 дня назад +1

      Interesting question! Certainly if one was going to use it on a 'high' voltage, like one does with a neon bulb for example, one would definitely use a current limiting resistor. However, in the case shown here where the device is running at this low voltage level, then I don't think it is necessary.
      When building up this circuit, I had no idea what 'HT' to use for the display, although I knew it was very low, so started off by connecting it up to a 0-20V PSU. Using this, I was able to slowly ramp it up and note when the display fluorescent anode started to glow. Around 9 volts if I recall correctly. Taking it slowly up to about 20 volts, (the max . for the PSU) then it was about the same brightness as one would see on one of these displays in normal use. Hence, I don't think at these voltages a limiting resistor is necessary and therefore didn't use any for the demo. you've seen. Hope this helps!

    • @Enigma758
      @Enigma758 23 дня назад +1

      @@lishaton I've seen circuits where sometimes they are used and sometimes not which is why I ask. I think in most cases, the current draw of the anodes/grids is low enough such that resistors are not needed. I suppose one could measure the current to be sure. I've seen 10k resistors being used when driven by NPN, but that is because it is a common collector configuration. Thank you for responding.