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  1. R

    Limiting Mains current.

    I think I will not use an isolation transformer then as it is bulky and expensive. All controls will also have plastic covers, and there will be no exposed metal parts. I think I'll earth the metal cases of the pots too just in case a cover gets broken off. Oh yes, R3 is a bit low. Yes D9 is...
  2. R

    Please recommend a Good Electronics Book

    Thanks for the suggestions  :)
  3. R

    Please recommend a Good Electronics Book

    Cybernetics degree. Currently studying physics. Made low volt, low power electronics (mostly digital) for work and hobby for about 15 years. Digital electronics is pretty straight forward. Gets a bit more tricky at high frequency, but things would just not work rather than blow up as with the...
  4. R

    Limiting Mains current.

    Hi, Thanks for the info and pics. I had somehow not noticed the posts had gone on to a second page!  ::) I'm still a bit confused about, the isolation / safety. Some points and questions below. The unit will be self contained and in a plastic box. The 12V transformer  is just for changing the...
  5. R

    Please recommend a Good Electronics Book

    Hi, I want to get a good book on electronics. My main interest would be Power Electronics. I'm not a complete beginner, so it doesn't need to cover basics.. I've heard mentions of "The Art Of Electronics" but this was last revised in 1989. I'm hoping for something more modern that would also...
  6. R

    Limiting Mains current.

    The control electronics will be powered form that 12V regulator and another 5V regulator attached to the same supply. Good point, Do you think I'll need a diode rated for more current? I haven't picked one yet, but yes probably a few amps to be on the safe side. I see your point. So maybe I...
  7. R

    Limiting Mains current.

    Oh, I don't know why I put the MOSFET (actually it will be an IGBT) like that, I should have noticed before I posted! I'd also forgot to add a resistor. Revision attached. Its not a coil gun, but it is for pulsing a coil. I cant use a Thyristor because it would not switch off until the cap is...
  8. R

    Limiting Mains current.

    Thanks. Yes, I saw the isolation transformers would be about 5kg ! I will avoid that if possible The attached circuit shows the power electronics that I have in mind. Another question. Should I make all my GND common with mains earth?
  9. R

    50V, 50A H-Bridge IC needed

    Ok, Thanks for your help  :)
  10. R

    power factor improvement and reduction of total harmonic distortion of rectifier

    I like tomatoes.
  11. R

    Battery charger for hilti cordless drill

    The link below shows a diagram with a simple charger based on a LTC4060 http://freecircuitdiagram.com/2008/08/28/autonomous-fast-nimh-battery-charger-using-single-chip-ic/
  12. R

    Limiting Mains current.

    Yes, I looked at some isolation transformers but I wasn't sure if they would actually limit the current. What do I need to look for in the specs? Maybe I can just use a 100W transformer as the peak load would be brief enough not to overheat it  :-\ Since the high currents would only be brief, I...
  13. R

    Polarity Switch

    Wow, Is it hot in here  ;) I don't want to get into the argument so I'll just answer the original questions. I was looking to use a VNH3SP30-E as is it a H-Bridge device that makes things easier but it was not powerful enough for me. I'll now be making my own h-bride. Its a lot more effort...
  14. R

    Limiting Mains current.

    The capacitor will be about 1000uF. I'd discharge it before it reached full voltage. Hoping this could be done every second or so. It's UK voltage so the rectified voltage could be over 300V. I'm wanting to limit the supply to 500W. If I use a 200 ohm resistor the power dissipated would be...
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    50V, 50A H-Bridge IC needed

    I've got some STP40NF10L, and IRF5210PBF MOSFETs handy so I think I will use those as they are N and P type respectively and both rated for 100V and 40A. I also have some comparators, so I will just use those for the level shifting. Thanks
  16. R

    Limiting Mains current.

    Hi, I'm making a circuit that in part will charge a capacitor from the mains. When the cap is empty the current would be very large. I want to limit the current to about 1.5A so that the rectifier is not damaged. Should I just use a resistor on the rectifier output, or should I use a capacitor...
  17. R

    ultrasonic transducer 1 - 3mhz source

    I would expect they had them custom made for the experiments they were doing. There should be some contact information for the authors of the paper on the first page or something in the references. I think that would be the best place to look.
  18. R

    50V, 50A H-Bridge IC needed

    :-[ I thought 5V would be too low to switch the mosfet properly. I was thinking of using some comparators to convert the voltage level to around 12V. I chose 10V zeners because that is high enough to allow the mosfets to switch on but low enough to protect them against any transients. I made...
  19. R

    Controlling LED Piranha with PWM controllers

    Yes, you are going to need more ODC15 units if you want independent control over the LEDs
  20. R

    50V, 50A H-Bridge IC needed

    Thanks again. I really appreciate your help. Does this diagram look ok? I've not found an appropriate pair of mosfets yet. I find one type, but then can't find its equivalent of opposite polarity. I'll update when I find them.
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