Recent content by matt09

  1. M

    0-30V Stabilized Power Supply

    Thanks guru, the derating graph shows a temperature of 100'C at 175W per transistor so providing they are cooled below this temerature they would work? You say about cooling them in liquid nitrogen but isnt the total dissipation to the heatsink the same except with the 3055's it's spread across...
  2. M

    0-30V Stabilized Power Supply

    Would this be much better than thhe 3055's, I have loads lying around? http://www.datasheetcatalog.org/datasheet/mospec/2N5683.pdf -- 2N5686 They're massive things with a 50A collector current and 300w handling, could I sub them and get away with just 2 handling 175w each for a 10A output? I...
  3. M

    0-30V Stabilized Power Supply

    Thanks redwire, I'd prefer to use the 3055's as I have a few already but can the problem not simply be solved by paralleling two 139's or using a more powerful substitute such as the D44H11? I'm guessing I could change the current limiting adjustment by playing around with the value of R18? I...
  4. M

    0-30V Stabilized Power Supply

    Thanks for the reply guru, would the circuit still work if I replace R7 with a 0.1R power resistor for minimum power dissipation or will this mean further modifications are required? Regarding the BD139 burning, could I just parallel 2 of them with another 1k resistor? I wasn't so sure about...
  5. M

    0-30V Stabilized Power Supply

    Hi everyone, If I used the latest circuit with 5 power transistors can I achieve a 10A constant supply with a verry large heatsink and fan, it works out to about 65W per transistor? I have a 26.3VAC 10A+ transformer with massive 2.5" wide core. Would anything else need changing other than...
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