Recent content by sec

  1. sec

    Simulation in Linux?

    There's a site dedicated to open-source EDA software at: http://opencollector.org/ Not all of it's for Linux/Unix, though, but most of it is.
  2. sec

    "Safe" 5000 V

    Alun has explained the theory pretty well, but on the practical side, you'll want to build something like a Van de Graaf generator, or a Tesla coil. Search around on the Internet; there are plenty of resources out there. A forum dedicated to these (and other) HV topics can be found at...
  3. sec

    The PIC & The ATX PSU

    Neat! A few things worth noting... Pin 9 is +5VSB. This pin supplies +5v so long as the mains power is connected -- even if the machine is powered down. Well, unless you turn off that switch on the back of the PSU, that is. (You apparently know this; I'm just clarifying for the benefit of...
  4. sec

    Rubber heat sink insulators

    Thanks, that pointed me in the right direction. Some googling revealed that pre-cut insulators made out of this material go by the trade name 'Thermo-Pad', and sell for about US$1-1.50 for 5-packs of the most common shapes.
  5. sec

    Rubber heat sink insulators

    In some commercial devices, I've seen power semiconductors that are insulated from their heat sinks by a grey, rubber-like insulator. Does anyone know what this material is, how its thermal transfer properties compare to the classic mica washer/silicone grease combination, and where it can be...
  6. sec

    transistor uses

    In that case, you might want to look into using a FET.
  7. sec

    +- 15vdc Dual Converter

    Oscillator coupled with a Greinacher voltage doubler, right? In theory, it should work. I'm not quite sure about your implementation, though. It looks like you've grafted two different schematics together to get that schematic. I'm curious about the left-hand side of the circuit, as it...
  8. sec

    Car stereo amplifier output ratings

    Take a look at: http://sound.westhost.com/power.htm for a discussion of the wacky world of power measurements for the purpose of advertizing. :)
  9. sec

    4N25 Schematic check

    I really don't understand what the optoisolators are for. Isolating the fans? Isolating them from what, or isolating what from them? If you were using the output of some sensitive IC to drive the fans, then I could see it, but a simple switch does not need isolation from the fans, nor do the...
  10. sec

    What is a reasonable frequency?

    Sorry, but without more information about what you're trying to do, we can't really give you a good answer. As for transistors, they will all have a maximum frequency for which they're good. This depends on the model of transistor, and can range from a few kilohertz to a few gigahertz. You'll...
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