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Showing content with the highest reputation since 01/16/2018 in all areas

  1. 1 point

    0-30V 0-3A Latest Data

    Hi all, Finally after some months have gone by, my build of the Power Supply is done. I have used liquibyte schematic Rev. 8 and had made the cirquit board according to the Gerber.zip file he posted here: 0-30V Stabilized Power Supply Page 88 posted October 6, 2014 "http://electronics-lab.com/community/index.php?/topic/29563-0-30v-stabilized-power-supply/&page=88" I left out D10 and R15 as per his description. I have plenty of boards leftover if someone has a need for it. There was only one mistake liquibyte made which have outlined in one of the pictures uploaded here. I was fortunate enough to get a big case with a Toroidal transformer from the scrapyard. Also many parts are recycled from various sources. Regards, William
  2. 1 point

    Power supply

    You forgot to say if the 10V output from your power supply must be AC or DC. You also forgot to say if the input is AC or DC and its voltage and frequency. Did you know that the output power from your power supply will be 10V x 1000A= 10000 Watts? Where will it come from? What will it be used for?
  3. 1 point

    0-30V 0-3A Latest Data

    Hi all Ok, this is my end result. Built and tested and works quite well. I started with the version posted at the start of this thread. However I had a couple of problems with the current limiter. I didn't have much success with the current limiter clamping the input of U2 - sometimes it would not go right down to 0V, sometimes it would go just below. Just below was a big problem for me - U2 would start to oscillate, with bad consequences for anything connected to the output of the Q4... It would then drive the output high just when I wanted the current limit to become active I should add that I did not use TL2141 or MC34071s, this might be the root of my problem. I fixed this issue with a small change to circuit layout rather than going to expensive opamps. My mods (compared to the circuit posted on start of this thread): * current limit - I removed D9. To replace this, I added another BC548 - the base is driven by the current flowing through the current limit LED. The collector of this BC548 clamps the output of U2 (exactly like the existing BC548 driven by the negative rail). This arrangement means we don't care how close to its supply voltage the output of U3 can go. It avoids the possibility of driving the input of U2 out of spec. Clamping the output of U2 is much more like how the integrated voltage regulators work. It seems better to my mind, to keep U2 out of the loop when current limit is active. [Edit: note that U2 will need a small heatsink with this arrangement] * some rearrangement of the opamp power connections, for all three opamps... U1 & U3 are run via 15V zener diodes, to give a supply of approx 30V. That allows almost any cheap opamp to be used for U1 & U3 (741s or TL071 etc). U2 is connected to unregulated 44V and to the output side of the 0R47. * I used a MC33171 opamp for U2. It is high voltage, but much cheaper (they are £0.60 in UK) than TL2141 or MC34071 (both are £5 here). It is a low power IC by comparison. * 0-30V 4A transformer. * 2 x 6800uF smoothing caps.a big thanks to the contributors on this thread for their efforts, my project was greatly speeded up by borrowing a lot of their ideas Edit: * I also changed the 0R47 to 0R2, as the 0R47 generated too much heat at 3A for my liking. This also means R18 changes to 330K. These two values are not shown on the schematic here.
  4. 1 point

    high voltage electric arc

    i need to create voltaic sparks that jumps from one electrode to another between a medium of air. sort of like jacob's ladder. the distance of one electrode to another is about 0.5". i gather that the breakdown voltage of air for said distance is about 4kV. i'm targeting more of around 20-30kV, just to be sure. the sparks do not have to last long, just about 1 sec, max. the purpose of this simple contraption? i want to create a sustained jacob's ladder, rather than one lasting only a second (as the described contraption does). so what this contraption will do is apply the breakdown voltage, ionizing the air and then the sustained high voltage will be supplied by my DC arc welder that outputs 25V @ 50A. don't worry, i won't put the two to be electrically parallel to each other. the contraption has to be very cheap (would simply winding a step-up transformer be enough)?? i've tried different sources, the cheapest i found was simply buying a cheap stun gun (around $10-20) than can supply a few million volts -- pretty good. but the laws in canada does not allow the trade of any sort of weapon (even for self defense) whatsoever. i've tried looking at neon sign transformers but they cost at least $50.
  5. 1 point
    Kevin Weddle

    High Voltage low amperage

    Generating a very high voltage with a small battery is an interesting idea. In theory, a transformer can produce any voltage, depending on it's turn ratio. They can also be cascaded. Are there any designs that utilize cascaded transformers, and if so, why isn't one transformer used?
  6. 1 point

    negative ioniser

    Hi all, I am looking for a circuit that operates in 9-12 DC and will generate voltage in 2-3KV range with negiligible current. I came across many designs but interested if anyone knows any circuit that uses common step down transformer with primary and secondary reversed as the first step in conversion.I am planning to use Cockcroft–Walton multiplier to increase the voltage from transformer. Flyback transformers are difficult to find /not familar for me to use.But would defenitely consider if its readily available I came across this circuit and like to know if something similar can be tried with a step down transformer http://www.aaroncake.net/circuits/flampdrv.asp If anyone know any schematic with small flyback transformers I would be glad to try.I am only concerened about availability. The whole purpose is to make a negative ion generator to clean dust from my vinyls. I donot want to use the ones based on Pizo electric but somehing that will generate a massive negative ion flow that will neutralize all sticky dust on my LPs .The prime consideration is making it as small as possible.
  7. 1 point

    negative ioniser

    The same basic blocking oscillator circuit, normally used to drive a flyback transformer, can also drive a centre tapped or dual primary mains transformer. Here's an example of a capacitor charger using a mains transformer with a centre tapped primary. It should be able to drive a voltage multiplier circuit.                     C1 1 uF                   D2 1N4948   R2                 +------||------+        T1    1.2kV PRV  1K 1W                 |              |           +-----|>|-----/\/\---+------o +                 | R1 4.7K, 1W  |   red  ||( blk                 |                 +-----/\/\-----+------+ ||(                     |                 |                  yel )||(                   +_|_ C2  + o----------------------------------+ ||(                    --- 300 uF                 |                  red )||(                   - |  450 V                 |      +--------------+ ||(                     |                 |  Q1  |                ||( blk                 | 6 to 12         |    |/ C                  +--------------------+------o - VDC, 2A         +----|    2N3055    Stancor P-6134             D1 _|_   |\ E           117 V Primary (blk-blk)         1N4007 /_\     |            6.3 VCT Secondary (red-yel-red)                 |      |  - o------------+------+ http://www.repairfaq.org/sam/samschem.htm#schssi
  8. 1 point

    Small vacuum tube Tesla coil

    nice old fashioned work is it dangerous to touch the fling electrons ????
  9. 1 point

    My ZVS Flyback Driver with pcb

    This is my ZVS Flyback driver with pcb/desinged. It is very simple. ZVS Flyback Driver ;D <Y> ./'\.
  10. 1 point
    Silent Jack

    High Voltage low amperage

    No, lead acid batteries are far too heavy. I was looking at maybe NiMH or more likely some LiPo batteries commonly used on RC cars and the like. Looking at 3-6AmpH class batteries. Might lean towards 12V, since there is so much standard stuff for that as far as wiring and other components. Safety is of course important and any good suggestions on grounding/shielding are welcome and appreciated.
  11. 1 point
    Kevin Weddle

    High Voltage low amperage

    A transformer will deliver a high enough voltage that you want. High voltage transformers are expensive, but can usually be found in electronics products no longer used, and be cascaded for high voltgage. Be aware that high voltage burns and shock can occur, and a high enough voltage can lay you in the hospital.
  12. 1 point

    High Voltage low amperage

    10,000V at 0.02A is 200W which is a lot of power for a little power supply.
  13. 1 point

    High Voltage low amperage

    Possibly a flyback converter? They can usually be output current limited by limiting the current availiable to the transformer. Do you need it to be highly efficient or are you not too fussed?
  14. 1 point
    Here is all I have Playstation2_Repairguide.pdf
  15. 1 point

    0-30 Vdc Stabilized Power Supply

    I attach it here also for fast view...
  16. 0 points

    How to choose a high voltage relay

    The current rating is not a problem. It's better to go higher than lower. Using a power relay to switch low current signals is only a problem at very low voltages. The problem with using a lower voltage relay is the contacts can arc over and what's worse it it could be unpredictable.The relay may seem fine most of the time but it could suddenly arc over due to ambient ionising radiation.
  17. 0 points
    thought so..... T_T what about my idea of a semiconductor device (somewhat like a diode)??
  18. 0 points

    Measuring low current on high voltages?

    No never remove the fuse from the meter. The meter's insulation is only 1kVDC, if you try to measure 100kV, an arc will jump through the case which will both damage it and you'll get a nasty shock.
  19. 0 points
    Silent Jack

    Tesla Coil Ebook

    There's numerous levels of teslas available with good detail on construction and theory on www.instructables.com . I like the pictures and step-by-step instructions they provide there. And they cover anything from small palm scale coils to large, light up your barnyard size ones. Give it a peek.
  20. 0 points

    How to Maintained High Voltage Problem?

    please give more technical details. i can't clearly get what you want ::)
  21. 0 points

    Tesla Coil Ebook

    It is very well explained in the links provided by Hotwaterwizard above!
  22. 0 points
    Here is what I have [attachment deleted by admin] SONY_PLAY_STATION.PDF the-ultimate-playstation-manual.pdf
  23. 0 points

    Gould 1421

    Yeah... Me too, me too... I was lucky though, found a service manual for Gould OS300 by googleing it and there it was, at least i got my OS 300 working. But those other 2 1421's are still dim, only power light is on but no trace.
  24. 0 points

    Surround Sound for car audio

    The Hafler opamp circuit should do what you want. The New Japan Radio IC datasheet doesn't explain what it does. It has graphs showing bass-frequencies-only, some phase-shift amounts and its block diagram shows a subtraction circuit for both channels but doesn't show what is subtracted.
  25. 0 points
    BEL187 npn Transistor http://www.bel-india.com/BELWebNew/UploadedFiles/Products/Plastic_package.pdf#search='BEL187%20npn' http://www.electronicsforu.com/efylinux/circuit/feb2003/Automatic%20Heat%20Detector.pdf NPN Driver/Output Transistor Plastic Package TYPE BEL187