Plasma speaker using SG 3525

Discussion in 'General Electronics Chat' started by bogdan001, May 17, 2011.

  1. bogdan001

    Thread Starter New Member

    May 17, 2011

    It's kinda the first time when using this kind of forums.

    I'm a student at Electrical Engineering and Computer's Science.

    I'm trying to build some kind of plasma speaker using SG3525 but i do have some questions regarding the pins of the SG3525AN IC.

    First i'm trying to drive 2 mosfets for obtaining an electric arc (schematic depicted in page 6, fig. 11) but after connecting the 15-13 pins to Vcc source; the Rt, Ct and pin 7 (discharge) to the ground i have oscillation at pin 4 in some form of almost instantaneous impulses on the oscilloscope but the outputs A (11) and B(14) appear to have 0V between them and GND.

    Can anyone answer me why is that happening?


  2. SgtWookie


    Jul 17, 2007
    Hello Bogdan,
    You have "hijacked" this very old topic:
    While your question is related to the original posters' questions, it is preferred that you open a new topic, as otherwise the thread/topic can become confusing very quickly. Be aware that a Moderator will probably move your question to it's own topic.

    You mentioned (schematic depicted in page 6, fig. 11), but you did not provide (a link to) the document; the datasheet that I have for this IC was published by OnSemi and does not have a figure 11 on page 6. Since this is an "industry standard" part, it is made by a large number of manufacturers; the datasheets will not be identical between the various manufacturers and may also change over time. Without having the schematic for reference, it will be difficult to suggest what might be the trouble.

    However, if pins 8 (Csoft-start) or 9 (Compensation) are held low, or pin 10 (Shutdown\) is held high, then you will see a logic low output at A (11) and B (14). Also, if pin 10 is left "floating", you may have erratic operation due to electrical noise.
  3. bertus


    Apr 5, 2008

    As SgtWookie already said, you hijacked an old existing thread.
    I moved the posts to a thread of your own.