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  1. vainajala

    PSU 0-60Volts

    Hmm...I just thought that ten parallel power transistors in a PCB might require many jump-wires (at least for single-layer board)... But yes, it's propably better to move the mosfets from the board. I wonder what is the heatsink's thermal resistance requirement? Even though I have another PSU...
  2. vainajala

    Passive audio filters

    With some tinkering with 5spice, i added the phase information into the graph. How does it look like...? I just experimented with different ccomponent values. That's all. :P
  3. vainajala

    PSU 0-60Volts

    Ante, Audioguru, Could this be used with supply voltage of about 45 volts? At least the PCB-routing might be difficult because of the amount of transistors... ::)
  4. vainajala

    Who is using the oldest computer?

    I've attached a pic in case you interested... it's really not very complicated system, but it works :) In my opinion, best cooling solution would be Innovatek's "Konvekt-O-Matic Standard". It's basically a huge heatsink, which requires no fan at all. It has enough heat capability for normal...
  5. vainajala

    Who is using the oldest computer?

    I have liquid(water)-cooled Athlon XP 2700+ at my home. It's not overclocked, but i like that it's bit more quiet because it doesn't need noisy CPU fan. One adjustable-speed 120mm fan at the radiator keeps the CPU and GPU temp well below 45-50
  6. vainajala

    Passive audio filters

    Response graph.... The extra parts L5 and R6 in schematic are supposed to perform baffle-step compensation, to attenuate the midbass-midrange quite a bit.
  7. vainajala

    Passive audio filters

    <bump> I understand this is not really a forum about loudspeakers, but here's some updates... This might be the final crossover's circuit... I just need to wait until the drivers arrive to me (about 2-3 weeks maybe). And when I get my "testing gear" (a speaker measurement...
  8. vainajala

    Passive audio filters

    Hello Audioguru, and thanks for your reply :) Actually, I was going to connect the drivers with opposite polarity. This really got me thinking of using 18dB filters, for their better performance. My amp is a Sony's model STR-DE585, not a welding machine ;D But seriously, I think it's rated...
  9. vainajala

    Passive audio filters

    Hi, I have in mind building small 2-way loudspeakers to my stereo system, because the old speakers are in so bad condition. The bass-element's foam surround has come really "weak" and it has many holes even though the surround hasn't been touched by hand practically at all! The loudspeakers are...
  10. vainajala

    Unknown component(s)

    Thanks, Ante! :) So it's a 5V regulator (like 7805), but with slightly higher max. output current and lower max. input voltage...
  11. vainajala

    Unknown component(s)

    Hi all, These components are from old PC power supply, the problem is that I can't find any info about the left component in the picture. The right one seems to be PNP Darlington transistor... Could someone help a bit?
  12. vainajala

    Help please, Need 12 V DC Power Supply for ATX Mainboard

    Andy, If you don't have very new (=power-consuming) PC then this article might interest you... ;) http://home.concepts-ict.nl/~cybersake/carmp3/ Ante, do computers need voltages other than +-12V and +-5V? Because I remember there was also +3,3V... ???
  13. vainajala

    Blinking LED

    Check out this... 8) http://www.lsdiodes.com/5mm/5mmflash.htm
  14. vainajala

    PS1 Car supply

    AJB2K3, I agree also to Ante's suggestion. it's a simple and powerful circuit, and with good heatsink it doesn't need any pass transistors for this application. There's many circuit examples in the datasheet of LM338, I suggest you to take a closer look... :)
  15. vainajala

    Switching power supply

    Audioguru, thanks for information! I must try this when I have more time for this project... Ante, maybe the MAX626/627 driver could be used to drive the dual P-channel FETs then? And, should I get inverting (MAX626) or non-inverting (MAX627) driver? Also the max. 18VDC supply must be arranged...
  16. vainajala

    Switching power supply

    I decided to test N-channel MOSFET as a switch transistor, and it worked well! Typical efffiency was 77% with 21W and ~74% with 55W. The heatsink was so small that the FET heated pretty quick with 55W and higher loads, so effiency in these loads is more "approximate". I had to make modification...
  17. vainajala

    Switching power supply

    About darlingtons... I tried a darlington transistor configuration with dual MJ15004 transistors. 55W halogen served as a load, again. Unfortunately I didn't measure the performance of that circuit (Iwas in bit of a hurry...), but the output-transistor got very hot (i almost burn my finger when...
  18. vainajala

    Small plasma experiment

    I found this simple "OAUGDP" plasma panel experiment. It's quite a simple device but it looks cool in my opinion! ;D Has anyone tried to built anything like that? Anyway, nice use to a unused ignition coil lying in a junkbox... http://jlnlabs.imars.com/plasma/html/s_gdp1.htm...
  19. vainajala

    Switching power supply

    First of all, thanks for your help, it's surely needed ;) Audioguru, What do you think about using three MJE2955's in parallel, with 0,1R emitter resistor in each? By the way, are the "equalizing resistors" needed in switching applications? As far as I can understand in this transistor's...
  20. vainajala

    Switching power supply

    Some testing with 30VAC 300VA transformer... I have made some changes to the device: I put transistor and diode into heatsinks, and added a trimpot to adjust the voltage. The 150R base resistor heats up very quickly! I changed it to a 11W 150R power resistor and it got up to 70
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