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  1. (*steve*)

    Burleigh PZ-70

    Hi @Mudflap, I just realised that I confused two pieces of equipment in this thread. The device with the tube is an APH-1000 high voltage power supply. My Burleigh PZ-70 seems to work fine. If you're still around, I have attached a photo of mine. Tell me which resistors you're talking about...
  2. (*steve*)

    Voltage Amplifier

    Your wish is my command... Hmm unfortunately it's only 0-1000V, it's not bipolar (sorry about that). Here's some photos: There's nothing much exotic in there.
  3. (*steve*)

    Transformer primaries in series, secondaries in parallel -- ok?

    In answer to a previous question which basically asked why an arrangement like this was not suitable: If the load on the top transformer increases, the current through the primary winding wants to increase. In order to do this, the current through the bottom transformer must increase also...
  4. (*steve*)

    Transformer primaries in series, secondaries in parallel -- ok?

    p.s. I write 240 VAC because we don't have 220 VAC, or 230 VAC (or incidentally 240 VAC). For historical purposes, we have 254 VAC.
  5. (*steve*)

    Transformer primaries in series, secondaries in parallel -- ok?

    Here is the solution I think we agree on: There are two 240V primaries in series operating from 240V, thus giving about 1/2 the voltage across each. This guarantees an equal current through each transformer primary (but not necessarily an equal voltage across them). Each of the secondaries...
  6. (*steve*)

    Voltage Amplifier

    I think I paid $50(ish) for my single channel PZ-70. I should take some photos from inside it. It's remarkably simple.
  7. (*steve*)

    Voltage Amplifier

    If you're at a university then they may already have some high voltage power supplies that can be controlled by an analog voltage, or even a dedicated high voltage on amp (I picked up one of the latter on eBay for a song). The device I have would be happy in a rack, and offers a couple of...
  8. (*steve*)

    Is it possible to etch pre drilled proto board

    If you look at how commercial boards are made (it's essentially an additive process) then the answer is yes. However... It is most definitely NOT simple.
  9. (*steve*)

    Cells with different voltage in parallel????

    That is true IF you are confusing series with parallel.
  10. (*steve*)

    Transformer primaries in series, secondaries in parallel -- ok?

    Good point. I'm pretty sure the windings will be close to identical, but there's no point in risking it. I'll place one pair in parallel feeding a single bridge rectifier, and the other two windings each into their own bridge rectifier.
  11. (*steve*)

    Need recommendation for rheostat or potentiometer

    A rheostat with a sufficient power rating would probably anchor your hovercraft to the spot very effectively. PWM would be the way to go. Restricting the airflow would also probably work well.
  12. (*steve*)

    Is it possible to etch pre drilled proto board

    It sounds like you have matrix board. Etching removes the copper in areas you don't want it. Martix board has no copper (or many variants don't -- some have pads). In any case, there is no excess copper to remove. Building projects on matrix board isn't too hard. It essentially provides...
  13. (*steve*)

    Transformer primaries in series, secondaries in parallel -- ok?

    Each transformer (call them T1 and T2) has 2 independent 30V windings (call them S1 and S2). I plan to connect T1-P1 and T2-P1 in parallel; and T1-P2 and T2-P2 in parallel. I will end up with two 15VAC outputs which I can connect in series to get a 15-0-15 output.
  14. (*steve*)

    tripp-lite pr-60 transformer issue

    The important thing about transformers is that if they are hot on the outside then they're a lot hotter on the inside. That heat can damage the insulation resulting in an internal short.
  15. (*steve*)

    Server Move

    At the time it happened, I found I had no reason to remain conscious. I just went to bed... Actually, I was already in bed, I was just given the excuse to go to sleep.
  16. (*steve*)

    Transformer primaries in series, secondaries in parallel -- ok?

    I am after a transformer with a 15-0-15 secondary at several amps. Yesterday a couple of transformers landed on my lap (luckily they didn't land on my foot). Unfortunately they each have a pair of 30V windings. Can I connect the primaries in series and the outputs of the two transformers in...
  17. (*steve*)

    DC to AC converter

    Having been to India several times, I'm thinking that the reason for this is to operate the equipment when the power is out. The main problem is that 12VAC has a peak of +/- 17V. We may need to know more about what the equipment does with the 12VAC.
  18. (*steve*)

    Connecting electrical devices into DC grid - polarity

    In general you connect things in a way such that that terminal marked +ve is always more positive than the terminal marked -ve. This works for batteries, capacitors, radios, cars, and small furry creatures from Alpha Centauri. Given that you understand current and voltage sources, pretty much...
  19. (*steve*)

    How to change input voltage on DC-DC booster

    If that resistor says "000", then yes. But remove the resistor first.
  20. (*steve*)

    Solar astronomy taken to a new level for me

    Do you remember that pinhole finder I had on my camera? It works a treat for finding the sun. With the longest lens I have, the sun more than fills the viewfinder, so I feel your pain :-) But you probably don't have a hot-shoe. I don't use my tracking mount any more. It's simply too hard...
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