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Electronic flourescent tube starter

Discussion in 'General Electronics Discussion' started by jjj, Jun 17, 2022.

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  1. jjj

    jjj

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    Dec 18, 2008
    Since non-of the expert technicians is able to help me make the SIDAC circuit work, I'll have to forget i.e. lose the SIDACs ($40 spent) and settle for this EA circuit, kindly submitted by debe & bertus using 8 parts; since I only need to buy 15x cheap B151-500R.
    I'll just Uhu-glue the parts onto small pieces of table gladding material and wire 15 of them up for all our fluorescent tubes. I prepared it in this way: InstantStarter.jpg
    [​IMG]
     
  2. jjj

    jjj

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    Dec 18, 2008
    I just don't understand big manufacturers of fluorescent tubes, such as Philips, Osram, etc. for decades recommended using those lousy "flicker starters" that shorten the life of tubes. It might be that they were merely interested in selling more tubes?.
     
  3. Martaine2005

    Martaine2005

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    May 12, 2015
    Quite possibly, we’ll never know.
    Might also have something to do with being ‘green’. More efficient, newer technology?(laugh), cheaper to manufacture? (Probably). Price per unit come down? (Doubt it).
    They aren’t exactly the best for saving the planet.
    Nor are cow farts. Worst polluters known to man.


    Martin
     
  4. jjj

    jjj

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    Dec 18, 2008
    I just had a look for these Instant Electronic Fluoro Tube Starters: they ask $30.85 to $73.95 for each lousy starter, would you believe?
     
  5. ramussons

    ramussons

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    Jun 10, 2014
    You need a High Voltage spike across the tube with hot filaments. Where does that spike come from?
     
  6. kellys_eye

    kellys_eye

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    Jun 25, 2010
    The same department would likely sanction you for mis-gendering someone these days. Darwin's Law used to be all that was required - now we have whole departments to stop people acting like idiots.
     
  7. kellys_eye

    kellys_eye

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    Jun 25, 2010
    Not quite sure why you would want to use an electronic starter at all anyway. If I was at all bothered about 'quick' starting I'd be replacing the tube themselves with LED versions. New fluorescent tubes with the bog-standard starters usually light up at first flicker (or maybe the second) anyway. If yours are taking a lot longer then the tube itself may be failing therefore a good opportunity to replace them.

    If it ain't broke .... etc.
     
  8. jjj

    jjj

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    Dec 18, 2008
    Every time get another post... I hope that this post will be a working SIDAC starter circuit... but no, only beatings around the bush... :(
     
  9. kellys_eye

    kellys_eye

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    Jun 25, 2010
    Well you have the schematic and seem intent on building one (or 15) so please let us know how you get on! The ball is in your court (as they say) so please forgive the ramblings whilst we await your success - or otherwise. Or is there something else about the circuit that is puzzling you?
     
  10. jjj

    jjj

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    Dec 18, 2008
    As mentioned, my hope was that you experts will know why the SIDAC starter circuit fails to work, for I bought a batch of these SIDACs for about $40, trusting the circuit's layout. I liked it because it consists of only 4 parts!
    Now I cannot use the SIDACs, because something with that SIDAC starter circuit is not right and non-of you experts are able to make the circuit work. :(
    - It's only out of desperation that I turned to the next best circuit which requires further parts.
     
  11. Harald Kapp

    Harald Kapp Moderator Moderator

    12,456
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    Nov 17, 2011
    You've been given a rather plausible answer by @HarryA in this forum.
    Acc. to the datasheet the K2400E has a trigger voltage of 220 V (min) up to 250 V (max). Two of these in series make for a range from 440 V to 500 V. A 240 V (AC) sine voltage has a peak voltage of 339 V. The trigger voltage is above that voltage, so no trigger will occur. Unless you were able to create a voltage spike higher than 440 V...
     
  12. Harald Kapp

    Harald Kapp Moderator Moderator

    12,456
    2,985
    Nov 17, 2011
    I simulated your circuit. The diode and the capacitor will create a DC component that rises with time such that the voltage across the SIDACs indeed rises above 500 V. This will trigger the SIDACs and everything should work as expected.
    upload_2022-6-24_9-28-28.png

    Without the capacitor, no such DC offset builds up and the voltage across the SIDACs never reaches the trigger point:
    upload_2022-6-24_9-27-48.png


    So here we have, obviously, the source of the problem.
     
  13. jjj

    jjj

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    Dec 18, 2008
    All I needed is how to make the presented SIDAC starter circuit work because I built the simple circuit, but it just didn't work. - I'm not an electronic engineer, but able to build any working circuit successfully for as long it's a circuit that works!
    Thus, today I fiddled around with adding a 1uF capacitor; first in parallel which turned it on but made it buzz. Then I tried to connect the same Cap in series and it worked perfectly. The original SIDAC starter circuit had 3uF3 Cap, but all of my lamps haven't got this Cap. That's why my SIDAC circuit didn't work without any Cap. I simply didn't know that!
    I just built the SIDAC starter circuit without that Cap... and that's why it failed to work! For that, I needed your expert help!
    That's a bit crazy but that's how electronics function; one wrong or missing part or connection and it fails to work. You know that...
    My working SIDAC starter circuit should rather look like this:
     

    Attached Files:

  14. Bluejets

    Bluejets

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    Oct 5, 2014
    Yeah, I pointed to that yonks ago back in #6 but apparently went over the top and didn't sink in.
     
  15. Harald Kapp

    Harald Kapp Moderator Moderator

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    Nov 17, 2011
    Actually it isn't. The hint is in the very first image you posted: "charging network". The diode charges the capacitor during one half-wave of teh sinusoidal input voltage but blocks discharging during the other half of the input's sine. During that second half the voltage across the capacitor adds to the input voltage which in turn allows the voltage across the SIDACs to exceed the trigger treshold.
    The 47 k series resistor limits the charging current, it has no other function.
     
  16. jjj

    jjj

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    Dec 18, 2008
    Yes, I had that in mind, for it's also shown in the original SIDAC circuit (but not on its starter section) that's why I thought of trying a Cap. Good advice: - For hobbyists or electronic ignorants like me you need to show the required change directly in the circuit schematic; otherwise, (they and) I wouldn't know where to place the Cap.
     
  17. John Canon

    John Canon

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    Jun 1, 2022
    Wha Happened.jpg
     
  18. Harald Kapp

    Harald Kapp Moderator Moderator

    12,456
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    Nov 17, 2011
    The cap was there in the original schematic. Not using the cap was your own decision.
     
  19. bertus

    bertus Moderator

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    Nov 8, 2019
    Hello,

    The capacitor was also in the schematic in the link I posted in post #20.

    Bertus
     
  20. Bluejets

    Bluejets

    5,616
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    Oct 5, 2014
    .......... and for my next project, wooden spoke wheels for the new 4 wd.
     
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