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  1. Kain

    Convert 0-30V 3A PSU to 5A or more

    Here we go. Hopefully this is final ;D PSU_revised.pdf
  2. Kain

    Convert 0-30V 3A PSU to 5A or more

    Ok. That sounds bad now since I will end up redoing the board. Before doing so please check this schematic that I am posting now where I applied the recommended changes. I want to be sure that this is correct since dealing with that small dual layer PCB isn't exactly that easy (meaning it takes...
  3. Kain

    Convert 0-30V 3A PSU to 5A or more

    Ok guys. It seems that nobody is feeling like working enough to check the board I just posted. Well you better check other people's job if you plan to use it because I messed it up a bit - the footprint for the op amps was kind a wrong - distance between pins was way too high so I had to correct...
  4. Kain

    Ground a astable 555 at startup

    I believe you can try to add a simple transistor based switch to do this for you. You should place it so it will shunt the 2.2K pull down resistor of the monovibrator. Its base should be connected to RC circuit to time a short interval when you power up the circuit. What is the power supply that...
  5. Kain

    UV exposure box with UV LEDs?

    Well I didn't say that there is anything wrong with using good old fashioned UV tubes, but this doesn't answer the question. Thanks for the suggestion anyways :). Since it seems nobody had tryed it (no answers to the topic) I decided to try it myself. I got one UV LED from the local...
  6. Kain

    UV exposure and white LEDs?

    I might ;D
  7. Kain

    UV exposure and white LEDs?

    Alrighty. In case somebody is interested in the results, besides me of course ;D, here you go. I exposed precoated board under white LED's light for 10 min. The LEDs are rated 10000mCD so they are not exactly weak. I placed the board right infront of the lenses for maximum illumination and...
  8. Kain

    Convert 0-30V 3A PSU to 5A or more

    Well this is a good idea about the boards and the wires. I think I will use photo-exposure on a large sheet so there will be probly about 5 boards per sheet or so - I need to calculate. I still have one question though - the main power nets I did with width of 3mm. Since I lost my chart I was...
  9. Kain

    UV exposure and white LEDs?

    Oh well, it seems I will need to do trial and error - I have few high intensity white LEDs so I'll expose little piece to see how it goes 8)
  10. Kain

    Convert 0-30V 3A PSU to 5A or more

    Alrighty. Here is the double sided PCB for the project as I promised. It took me a while - I have other things to do too you know ;D. I included the separated Top, Bottom layers - they are all ready for print meaning you don't need to mirror anything. The only thing you will need to do is scale...
  11. Kain

    UV exposure and white LEDs?

    Well, if you check on ebay you can find pretty good deal - 100 UV LEDs for less than 10$ in total. I think this is more than cheap ;D. By the way, please if you know something about using UV LEDs for photo-exposure please post on...
  12. Kain

    UV exposure and white LEDs?

    Good to know. I think I read few days ago about different processes of making white LEDs and one was actually by combining RGB by adding dots of different compounds on phosphorus to make all 3 colors, thus white, but anyways. The main question is still would it be possible to work under this...
  13. Kain

    UV exposure and white LEDs?

    When using the photo-exposure method to transfer the artwork, we all know that it has to be perfectly alligned especially if we are making double layer boards. Since this cannot be done under regular light as we all know, I wonder if it can be done under light emmited from white LEDs? The reason...
  14. Kain

    UV exposure box with UV LEDs?

    Recently I was using the photo-exposure method to do some boards (I like the tonner transfer but sometimes I need to get more acurate ;D). I used my friend's exposure room to do it - he's having some huge lamps which emmit 75% light in the UV spectrum. However, I've seen that there are UV LEDs...
  15. Kain

    Convert 0-30V 3A PSU to 5A or more

    Dazza, I almost got you though, huh? ;D Just kidding. The blow off thing hasn't happened to me before but for I always use resistor to limit the curent down as audioguru suggested. Audioguru, doesn't the current protection limit the current down so it will serve the same purpose as resistor in...
  16. Kain

    Convert 0-30V 3A PSU to 5A or more

    Dazza, I think the application you are talking about can be achieved pretty easy - I mean the self turn off. In fact, you almost have it built in already ;D. If you noticed the LED that is used for indication would light up if the current limiter is working. However, as far as I understand the...
  17. Kain

    Convert 0-30V 3A PSU to 5A or more

    Yup. The resistor I will be using will be the one i posted about earlier - aluminium cased with small fins as you said.
  18. Kain

    Convert 0-30V 3A PSU to 5A or more

    I would use 2 monting bolts x 3mm so this is not a big deal. The real thing is that I took the 15W resistor off the board - it will be way better if it's attached on the box and link with short wires to the board since it will allow it to cool better i believe. This is why the board can be that...
  19. Kain

    Convert 0-30V 3A PSU to 5A or more

    Ok, since nobody posted any PCB for this project, I decided to finish the job. The board I have worked on so far would be double layer board since I was trying to make it smaller, I really hope you don't mind. I can do single layer too but it would be about the same size as the original. The one...
  20. Kain

    Double sided PCB, how to?

    I guess many people in this forum would like to use sometimes less space for PCB in their projects meaning that they will be trying to achieve higher PCB density. Sometimes it works with very good placement of the components, but I noticed that even if this is the case most components have to be...
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