Recent content by Blacque Jacque

  1. Blacque Jacque

    0-30 Vdc Stabilized Power Supply

    Hi Thomas, Yes that's exactly what I had in mind, take note though, they are only rated for full power when bolted to another larger heatsink or chassis, eg: the 25w types are only good for 9w on their own and remember to derate if you run them hotter than 25 degrees.
  2. Blacque Jacque

    0-30 Vdc Stabilized Power Supply

    Hi Audioguru, Thanks for the description of range switching. I prefer to use just pots rather than the range switch you describe, I will get both a 10 turn and separate pots for coarse/fine & decide which I like best. This psu might be overkill for gain testing transistors, one slip and BOOM!
  3. Blacque Jacque

    0-30 Vdc Stabilized Power Supply

    Hi Audioguru, I hadn't thought of a range switch, how would you implement this ??? Do you think current & voltage setting would be easier with fine & coarse pots instead of multiturn ones ? If the current setting range is from 2mA to 3A that's a big adjustment range, it would be...
  4. Blacque Jacque

    0-30 Vdc Stabilized Power Supply

    Hi All, I have an idea which may solve a difficulty raised earlier in this thread ie: you cannot see the current limit set point easily, particularly if you want to use a multi turn wirewound pot. Expanding my theory for current metering, you could use another opamp buffer to read the voltage...
  5. Blacque Jacque

    0-30 Vdc Stabilized Power Supply

    LOL, Ok final question, would I need a proper darlington or could I use 2 x BC557 for a discrete one ? Thanks for your help so far Audioguru.
  6. Blacque Jacque

    0-30 Vdc Stabilized Power Supply

    Aha, this is a theory test isn't it ? ;) Ok here goes: High value resistors are needed to prevent current leakage through the existing LED, probably 100x Q3's bias pair values, hence a darlington to get enough current gain to turn on the 2nd LED. Correct ? ( My transistor theory was never very...
  7. Blacque Jacque

    0-30 Vdc Stabilized Power Supply

    Hi Audioguru, The meters are powered by 2 x SR44 watch batteries per meter so I figured I could use a separate isolated 3v supply ( another winding on the transformer + reg/rec circuit maybe, or take the guts out of a wall wart?). I'll try them battery powered initially then add a supply later...
  8. Blacque Jacque

    0-30 Vdc Stabilized Power Supply

    Hi all, I've been considering building one of these supplies & reading this forum with great interest. I will be ordering a kit from my local supplier shortly & then upgrading it to the spec you guys sorted out. ;) I want to fit voltage & current meters & have obtained a couple...
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