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  1. Arouse1973

    Project Help

    Ah it might be because you haven't sent enough messages yet. Also check the file size.
  2. Arouse1973

    Consumption of a Led Matrix

    For running one LED of each type from 9 Volts at 20 mA then your resistor values are correct. So looks like my typical graph wasn't too far out for the blue one then, but I guess you have only tested one. :) Adam
  3. Arouse1973

    Project Help

    Hello and welcome to E.P. Do you have any information on the circuit that is used. Do you have a circuit diagram we can see and maybe some nice pictures of the unit. It's hard to tell just from a description of a fault. Thanks Adam
  4. Arouse1973

    Circuit Protection For Inputs In Hostile Environment

    The diodes you are suggesting may not work properly. They may give the impression they are working. This is why, if the inputs you are protecting have internal protection diodes as most IC's have now you may find the maximum input to this device is only +/- 0.3 Volts above or below the supplies...
  5. Arouse1973

    Consumption of a Led Matrix

    Apart from using a constant current source for each LED chain (with resistor removed) set to 20 mA, the best way is to power each LED from a current limited power supply and measure the volt drop of the LED. This will give you a true voltage drop for that current. The voltage drop will change...
  6. Arouse1973

    Consumption of a Led Matrix

    It's important you check the data sheet of the LEDs to ensure you have the correct source voltage, high enough to allow for the desired current but not too high that you dissipate too much power in the resistor which is a waste. Adam
  7. Arouse1973

    Consumption of a Led Matrix

    Yep, that's the configuration I had in mind. :)
  8. Arouse1973

    Consumption of a Led Matrix

    Hi Harold Firstly you should use a series resistor for each string that you parallel together. I am not sure if you knew that already. You then need to then calculate the resistor value using the LED forward voltage at the desired current. It then won't matter if the LEDs are mixed in colour...
  9. Arouse1973

    Wanted: Transistor Circuit Techniques Book

    It's not a book that covers all transistor applications but I think it's good for a basic understanding of amplifiers and switching circuits. I don't think you will find a book that covers everything. The Art of electronics does a pretty good job, have a look at getting a copy of that also. Adam
  10. Arouse1973

    Wanted: Transistor Circuit Techniques Book

    I have the book but in Kindle version sorry. Can you pickup a second hand copy? Adam
  11. Arouse1973

    Getting Signal Voltage From Source Power

    Do you mean the power equation P = I*V ?
  12. Arouse1973

    Have I bricked my Arduino Uno? Problems with uploading to board

    Where and when did you buy the Arduino? Did it work the first time? Can you show me a picture of the Arduino board please. Cheers Adam
  13. Arouse1973

    Question

    At what frequency are you planning on doing this? I hope you don't want to build an RF transmitter. What do you want to do with these radio wave. Radio involves the transmission of information. Thanks Adam
  14. Arouse1973

    Pi/L filter versus impedance matching network the same?

    The filters do both. They filter and match impedances, well if you get the values right :). If you want to change the impedance you scale the L and C making sure you keep the frequency response the same. if you want to change the frequency of the filter you change the values of L or C or both...
  15. Arouse1973

    Greetings

    Hi Col, good to have you here. Please do keep us posted on the progress of your project, it sounds interesting. Adam
  16. Arouse1973

    Hello new here

    Welcome to EP Red Chili, :) Adam
  17. Arouse1973

    Silly regulator question

    Here is a small selection for you to have a look at. https://www.amazon.co.uk/s/ref=nb_sb_noss?url=search-alias%3Ddiy&field-keywords=Buck+regulators Adam
  18. Arouse1973

    Silly regulator question

    Hi James A buck regulator will be much better in terms of efficiency than a linear regulator. However they do produce a bit of switching noise which you may have to filter out with an LC filter on the output. Adam
  19. Arouse1973

    Replacing Large PCB Pin-Headers/Eurocard?

    LOL, close enough :)
  20. Arouse1973

    Replacing Large PCB Pin-Headers/Eurocard?

    Yep, I agree with the Scottish bloke :) Adam
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