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  1. redwire

    0-30V Stabilized Power Supply

    liquidbyte,  what is the lowest voltage setting you are able to achieve with no load?
  2. redwire

    0-30V Stabilized Power Supply

    Does adding another shunt resistor to this PS,  outside of the  feedback of U2 and input of U3  have any negative effects on the voltage regulation.  I don't know the value of the shunt resistor but what about current regulation.
  3. redwire

    0-30V Stabilized Power Supply

    Have you considered something like this: http://www.adafruit.com/products/296.  Using AVR Studio 6 (free)you only need a usb cable to program the chip. No separate programmer is necessary.  If you plan to do future project then you may want to  consider a  Dragon.  I have a STK500 it is a bit...
  4. redwire

    0-30V Stabilized Power Supply

    It is not the programing language that will be the controlling factor but the microcontroller and set up.  Many AVR chips (used on many Arduino's)  have 10-bit resolution (2 raised to the power 10) resulting in 1024 different reading.  If you use the chip's internal reference voltage of 2.56V...
  5. redwire

    0-30V Stabilized Power Supply

    The two things to adjust are: 1.  Voltage limit.  The 20K trimmer connected to U2 is to limit output to 30V.  You will likely find that the 20K trimmer straight from the factory was set at approximately 10K and is right about where you need it.    Set P1 to the maximum output, then adjust the...
  6. redwire

    new here, any help guys? car horn question

    One way would be to acquire a Arduino board.  Then program one input (horn button) and 4 outputs signals to a relay board such as http://www.amazon.com/SunFounder-Channel-Shield-Module-Arduino/dp/B00E0NSORY/ref=sr_1_6?ie=UTF8&qid=1397060045&sr=8-6&keywords=relay+for+arduino which...
  7. redwire

    0-30V Stabilized Power Supply

    I had concerns that the traces were on the thin side as noted earlier  but  I still think you can rearrange parts  and small traces, and widen the power traces to use  1oz copper.  The overall placement is pretty good as the power traces are nearly a straight line on the left side of the board. 
  8. redwire

    New website for comparing PCB prices

    Well it will be their loss, because that it a handy reference that many will find helpful.
  9. redwire

    New website for comparing PCB prices

    Thanks,  a handy reference.  How about Advanced Circuits, www.4pcb.com?
  10. redwire

    0-30 Vdc Stabilized Power Supply

    xwasx,  I don't see the benefit in adding a bunch of parts (LM317, LM337 and resistors necessary to set the voltage) to increase the  precision of the upper and lower rails of the op-amps when most of the PS's life will be well within those ranges .  It seems controlling  the voltage to the...
  11. redwire

    0-30V Stabilized Power Supply

    liquibyte,  glad you got it going!    You have limited parts with Eagle, so it happens that you grab a device that has reversed leads from your actual part. 
  12. redwire

    0-30 Vdc Stabilized Power Supply

    I'm a little confused on what is real and what is simulated.
  13. redwire

    0-30V Stabilized Power Supply

    Yes, the price seems out of line with other board manufactures.  Your boards looks good enough and it is hard to make them yourself for that price!      I actually made an order from them for a simple rectifier board, similar to what you would use for your Radio Shack transformer.  I'm waiting...
  14. redwire

    Problem with output voltage of simple PWM DC motor speed controller

    Make sure you don't have a bad potentiomenter (R2).  Check its value during the events to see if this is stable.
  15. redwire

    0-30 Vdc Stabilized Power Supply

    xwasx,  What is the capacity of your transformer?  2.5 A is a healthy load.    I'm curious about the effects when the current is lower. Do you have a sketch of how you set up option  4) bf256 + zener6v2 + zener3v3.  It seems you measuring output of the PS but what was happening at the...
  16. redwire

    0-30V Stabilized Power Supply

    Liquibyte,  your board looks good.  The only thing that stands out it your  OUT+ and OUT - header is very close to the mounting hole.  I think there if enough room to miss the mounting bolt but if you are stacking board is may be more difficult to make connections once installed.  I probably...
  17. redwire

    Help with transistors

    Hi GoodmanMotor,  you are asking such a basic question that I don't think anyone is going respond becasue there is just too much information already at your fingertips by typing "What is a transistor"  "How does a transistor work".  There are ton of resources from Wikipedia to Youtube.  Why...
  18. redwire

    NEW 0-30V Switching Power Supply

    There are many economical switching power supplies units for sale but I had difficulty finding any complete designs (None in the Projects section) with proven results.  I know there are some disadvantages compared to a linear supply but many of the advertised units have reasonable performance...
  19. redwire

    0-30V Stabilized Power Supply

    Liquibyte,  Are you using EAGLE?  I would suggest shrinking the outline because most fabricators charge by the outer dimension.    The price is likely for a minimum of 10 boards at $20 each.  $200 total.  Better verify.
  20. redwire

    0-30V Stabilized Power Supply

    Do you intend to have the board professionally made?  Some board houses require a minimum of 3 boards (OSH Park)and you pay by the area.  If you only need 2 boards,  than you may want to make single boards and have one spare.  All of the traces are the same size.  My preference would be to...
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