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Spiking a Capacitor

  1. Mar 18, 2015 #1
    I have created a generator outputting 300v spikes at 333 spikes per second. Wanting to discharge spikes to
    4700 uF/400v capacitor bank and am having trouble calculating the cap discharge rate, and if a 555 timer is the appropriate tool for discharging the capacitance into an inverter. I am a new threader but I love listening to you guys input each other, especially when you disagree. Its like listening to Sheldon and Leonard! And I mean this in the most respectful way.
  2. jcsd
  3. Mar 18, 2015 #2


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    Staff: Mentor

    Welcome to the PF.

    Sorry, what you wrote is confusing to me. Why try to drive voltage spikes into capacitors? That's not an effective way to charge them.

    And what experience do you have with higher voltages? Charging a 400V cap with a 300V source does not leave a lot of margin. And that's a lot of energy storage -- what is this setup for?
  4. Mar 18, 2015 #3


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    Staff: Mentor

    Hi Mark. http://img96.imageshack.us/img96/5725/red5e5etimes5e5e45e5e25.gif [Broken]

    First, a 400v capacitor for a 300v spike sounds less conservative than I'd like. I enjoy fire crackers only on Guy Fawkes night.

    A lot depends on the current capability of your generator: a single spike may fully charge the capacitor to 300v, or it may barely add any charge. Is that 300v measured when there is no loading, or is the generator able to deliver 300v into just a few ohms?

    The NE555 works up to only 20 or 30v, so maybe you aren't expecting the capacitor voltage to exceed that?

    You say a "spike", implying it's of short duration, but its duration is nevertheless important.

    In summary, not enough information. :cool:
    Last edited by a moderator: May 7, 2017
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