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  1. vainajala

    Switching power supply

    Second pic
  2. vainajala

    Switching power supply

    I have now built the powersupply and tested it a little bit. I unfortunately can't test it thoroughly, because I don't have a variable DC-supply. I'll try it tomorrow with two car batteries in series, resulting 24V. I did some tests with a car battery charger as a mains supply, trying some 12V...
  3. vainajala

    Large Knight Rider project

    This is what the original version looks like...
  4. vainajala

    Large Knight Rider project

    Sorry, but I forgot to add one wire (from second counter's last output pin to first counter's reset pin) :P It might still contain errors, but I think this is the way to go... :)
  5. vainajala

    Large Knight Rider project

    Hi gamerscloset! I found this application from Philips' HEF4017 datasheet, and modified it a bit for dual counters... I think this would work nicely for you ;)
  6. vainajala

    Switching power supply

    That's OK, if you say so! You know, I'm just trying to make it "even better" and easier to use... ;) I posted a picture about a thing which confuses me. I hope you can answer. What do you think about the R12's value? Is it correct? The TL494 needs supply current of 15mA MAX. My transformer...
  7. vainajala

    Switching power supply

    Heatsinking of the MJ15004 (in TO-3) is a problem, should I do a mofidied version with, for example, parallel-connected two or three BD912's (in TO-220)? Because TO-220 is way more easier to heatsink than the TO-3 in my opinion... If I end up using the BD912's, I don't think that the TL494 has...
  8. vainajala

    Switching power supply

    OK, time to flood the forum again with my pictures ;D Well, actually it's the same circuit, with a soft-start feature that should limit inrush current when starting. The board measures about 10,5 x 7,5 cm, and I designed it with the soft-start components in place. If I ever get this thing to...
  9. vainajala

    Variable Power Supply 0-24vdc 5A more...

  10. vainajala

    Variable Power Supply 0-24vdc 5A more...

    Maybe with current sense resistor + op-amp + transistor driving the "FB" pin low, would that work? At least it might (and most propably will) interfere with output voltage setting resistors...
  11. vainajala

    Switching power supply

    TINA Pro didn't have it :( But I'll try one more program: 5Spice
  12. vainajala

    Switching power supply

    Ante: I'm downloading TINA Pro demo version, I'll have to check if it has the model...
  13. vainajala

    Switching power supply

    Ante: I thought that too, but I don't have the program. Do you know some good simulation program?
  14. vainajala

    Led Strobe Circuit

    this is off-topic At school we tried to "fry" some cheap LEDs with a 30V / 4A supply, some leds sent nice smoke signals, but some even exploded! Of course that wasn't very wise, but entertaining indeed ::)
  15. vainajala

    Led Strobe Circuit

    Ante, Yes, it just a matter of how short time they are illuminated. But what if somehow the circuit fails and continuos 2A goes through the LEDs... :-X
  16. vainajala

    Switching power supply

    I made the circuit with Eagle and modified it a bit. I have some MJ15004 transistors, so I'll propably use one of those Diode is ultrafast type, rated at 200V/8A Most propably I'll take the inductor from an old PC power supply I only hope that the Hfe of MJ15004 is high enough (about...
  17. vainajala

    Led Strobe Circuit

    Luxeon Star LEDs driven by some sort of oscillator circuit like in Ante's attachment might be really powerful! :) These are the only LEDs i know with up to 5 watt of power capability, too bad that they are very expensive... :P
  18. vainajala

    Switching power supply

    Thank you very much! :) Yes, i was aware that after rectifying and filtering the voltage might be too high for the IC to handle. However I found this picture in the datasheet, which is the solution:
  19. vainajala

    Switching power supply

    Hi all, I thought about building a power supply for a thermoelectric (peltier) cooler element, which maximum power is 122W @ 15,7V (~7,8A). I have a toroidal transformer whose ratings are 300VA and 2x35VAC, so dropping the voltage from about 40VDC (or something, I don't know the  exact voltage...
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