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Dual Polarity Adjustable Voltage and Current Lab Power Supply Worklog

Discussion in 'Electronics & Electrics' started by nux, Mar 31, 2006.

  1. OP
    OP
    nux

    nux Member

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    I'm borrowing a drill press tonight so I should have the holes drilled by Sunday. Then I just need to print out and transfer the top silkscreen layer so it looks all pretty and is easier to put on components.

    EDIT: Wont get the drill press till next weekend, so on hold for a bit longer.
     
    Last edited: Jun 25, 2006
  2. Shamrock

    Shamrock Member

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    uou probably need to play with the printer settings to get it to work right, there *should* be a setting to choose OHP sheets or gloss paper, if you don't choose the right paper type it will just become a big mess.
     
  3. OP
    OP
    nux

    nux Member

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    There is no 'Glossy' option, laser printers shouldnt print on glossy anyway as they're for inkjets. But when I tried I selected the Transperancy option.

    I'm going to buy another type of paper soon and try that next time, still I'm pretty happy with the results from my old laser printer.
     
  4. Kenny12

    Kenny12 Member

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    the amp psu i'm using used the LM338 regulators up to 5A constant current i believe and a drop in replacement of the LM317

    edit: oh and just make sure the rest of ur stuff can handle 5A too
     
    Last edited: Jun 25, 2006
  5. OP
    OP
    nux

    nux Member

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    Well took forever to borrow the drillpress.

    [​IMG]
    Click to view full-sized image!
    Holes drilled.

    [​IMG]
    Click to view full-sized image!
    Soldered.

    [​IMG]
    Click to view full-sized image!
    Done. The silkscreen hardly transferred at all. Maybe its because the board has lots of dimples on the non-copper side?

    I regret having everything brought out to headers now :p I have to solder up some pots and switches now before I can test it.

    EDIT: OK, I have wired up some pots and have both outputs working! Hooray. I will post some pics in a minute.
     
    Last edited: Jul 10, 2006
  6. Odje

    Odje Member

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    Hey nuxie1,

    I am designing a similar function generator. Is the Sym and THD adjustments dependent on the frequency? That is do they need to be adjusted again after changing frequency? I would like to use trimmer pots if they do not need to be adjusted again. Does changing to the other timing capacitor affect it?

    It looks like we have been down the same track. I Intended to make a decent power supply, ended up buying that. I recently got an oscilloscope. Next on the list is a Function generator and a Data Acquisition board which I intend to make. For the function generator, I looked at the MAX038 and the XR-2206 plus a few DDS chips. Settled on the XR2206 since it is available from Jaycar and the DDS chips are all SMD.

    [​IMG]

    EDIT: This thread should probably be moved to electronics forum.
     
  7. OP
    OP
    nux

    nux Member

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    Not sure, I dont think it changes too much with frequency. Especially since the datasheet has fixed resistors in the simple version.

    I haven't really had a chance to work on it for ages, but I want to get a better layout setup with a few more options (like DC offset and AC/DC coupling).

    I've also gotten a Tektronix 308 Data Analyzer added to my equipment, nice piece of kit.
     
  8. Odje

    Odje Member

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    Might have to breadboard a few designs and test them with a proper spectrum analyser at uni after exams.

    I am intending to have DC offset and an output amp on mine. Plus have Sine, Triangle, Square, Ramp and Pulse with adjustable duty cycle. I'm intending to power it from an on board 240VAC transformer to +/-12VDC.
     
  9. OP
    OP
    nux

    nux Member

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    Yep, thats similar to what I had intended. Maybe we can make a joint worklog and try and get a decent design worked out. :thumbup:
     
  10. Odje

    Odje Member

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    I'm up for it. My last exam is on Monday. Plus I am on a casual contract instead of full time at work now too. Although I am planning to use the time to work on my thesis, but things never go to plan.
     
  11. dakiller

    dakiller (Oscillating & Impeding)

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    Subscribing an interest. A decent function generator is something I'm missing from my workbench. Sine and squarewaves to ~1mhz would do me :)
     
  12. Goth

    Goth Grumpy Member

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    Maybe just take the XR2206 circuit you used before, add an opamp to the output along with a pot to add the adjustable DC offset.

    The XR2206 will give you Sine, Square and Triangle, right?

    If you want a ramp/sawtooth waveform you can use this, i used it for a uni project, and it gives a very nice, linear waveform, nicer than a 555. Nice simple circuit too, only a couple of opamps.

    A rotary switch might be a nice choice for selecting the output waveform.
     
  13. dakiller

    dakiller (Oscillating & Impeding)

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    I'm getting bigger ideas... Digital synthesis :D

    I think it is worth checking at at least for myself, it cant be that hard can it?
     
  14. Odje

    Odje Member

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    The SMD part is what is putting me off. I have never done SMD work except for the Tx/Rx device in the IrDA kits where the pitch was massive.
     
  15. dakiller

    dakiller (Oscillating & Impeding)

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    Nah, no problems with that, just need flux. Though I don't think hand etching it would be easy, but I'm willing to give that a go too, just depends how easy the PCB is to layout.

    I'll have to have a closer to look at what is involved, I dont think its too much, just a microcontroller to interface to it
     
  16. Odje

    Odje Member

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    I have made PCBs using the photo-lithography method back in high school. Since then I have made a few using Press n' Peal. I have not tried it with glossy paper method. My traces ended up being wider when I did it with Press n' Peal and became bridged with nearby tracks so I don't know how good it will be for SMD board.

    I need to learn SMD soldering, so anyone got any tips on where to start with that?

    If we are going to throw a microcontroller in, maybe it can measure the frequency, peak-peak, and offset and display it on a alphanumeric 16X2 LCD?
     
  17. ElusiveA

    ElusiveA Member

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    I did SMD for the first time a month or so back, thought it'd be really challenging but it wasn't, by the second IC I was sweet. The only slightly harder bit is you need to make sure you solder the components on in an order that you don't end up producing an area you can't get into (ie trying to solder an 0805 package in between 2 IDC headers, solder the package first).

    Other than that just use a really fine tipped iron. Oh and you will use MUCH less solder than you think, the joints are TINY!

    But if you can already solder through hole well, then its a snap to change to SMD.
     
  18. dakiller

    dakiller (Oscillating & Impeding)

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    I've done a few PCB's with press n peel but they've all been through hole but a mate has been able to get an SSOP IC on one but it was on the limit of what's possible. Sending off to get one made isn’t much of a problem for me either, I’ve got a few sources that I’ve had good results from.

    SMD soldering is all about practice really, knowing how solder behaves and thinking ahead, and use lots of flux.

    And I’m pretty sure to actually set the output function of the chip I linked or other similar ones you need a micro to set that, so unless you want to link it via a PC (maybe optional but shouldn’t be the only method), a few buttons and an LCD is going to be needed to set the frequency and all that. I don’t know about measuring the actual output with the accuracies of a micro trying to measure compared to the DDS chips actual output, I'd guess that the DDS would output a more accurate signal that a micro could measure anyway so just setting it is a good enough measurement to display.

    Off to read some datasheets...
     
  19. dohzer

    dohzer Member

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    Some time in the next week, I'm thinking of learning by making a practice board (toner transfer) with a few random IC package types on it, and using some sample ICs that I probably won't need/use.
     
  20. Goth

    Goth Grumpy Member

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    I've successfully mounted LQFP-32 devices on press-n-peel boards before, but not toner transfer with normal paper, i haven't tried it, but i reckon you could do it.
     

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