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power switching..

Discussion in 'Electronic Design' started by Paul Horwood, Mar 2, 2004.

  1. Paul Horwood

    Paul Horwood Guest

    What I have done:-

    I am using a 4017 counter chip, this is being triggered by a signal
    generator. The output of the chip is being fed to 2N3904 transistors, to act
    as a buffer and to run LED's.

    Now each of the LED's chase each other with each input pulse from the signal
    generator (yes, I know I could use a 555 timer to trigger, but that would
    not give me the variability I need for my apparatus, once finished).

    I was going to feed the outputs that feed the LED's to a optical isolation
    switch for fast switching for external voltages to power some solenoids. But
    am not sure if they will be able to handle the power I require. I want to be
    able to at least switch 240Volts, at best 1000Volts. This I think cannot be
    done very well with optocouplers, unless you know different.

    Would there be a much better way of switching the voltages required? Triacs
    I am told will not work very well at high frequencies, and the component has
    to have this ability. What ever is used will have to be protected from the
    back emf from the coils, I assume diodes would be best for this.

    So I am looking for a component that can switch high voltages at very high
    frequencies, i.e. 100-250Khz.

    Any thoughts or help would be great..
     
  2. CBarn24050

    CBarn24050 Guest

    why would anyone need to switch a soleniod at 100kHz?
     
  3. I read in sci.electronics.design that CBarn24050 <>
    Thursday detectors for time machines need to do that.
     
  4. Tim Wescott

    Tim Wescott Guest

    First: A 555 will go from 1Hz to 1MHz if you switch caps, or if you use
    stepped dividers -- you don't want to bother?

    Fourth: 100KHz into a solenoid? Why? At 1kV? Wow!

    Second: Do you need isolation, or just amplification?

    Third: I've never used 'em, but at those voltages the only things I see
    from manufacturers these days are insulated-gate transistors. They're
    supposed to be easy to drive (at DC, anyway), and have collector voltages up
    to the stratosphere. At 250V I'd be keeping a bipolar transistor or a
    MOSFET in my back pocket, because I _have_ used them. Protect your
    transistors from inductive kick with diodes, or diodes in series with
    resistors for faster coil turn-off.
     
  5. CBarn24050

    CBarn24050 Guest

    you can get around that problem by going forward 20 yrs for a more advanced
    coil.
     
  6. Paul Horwood

    Paul Horwood Guest

    thanks Tim.
     
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