Search results

Search Forums New Posts
  1. KJ6EAD

    LED Component Question: Total Newb Here

    Congratulations, you have an intermittent. It's probably a cold solder joint somewhere on the blue channel (circled). It could be in the connectors or on the LED board. You can probably locate it by poking around with a plastic stylus or small wood stick while the power's on. Don't use a pencil...
  2. KJ6EAD

    Level 2 newby with a few questions

    You won't find the type of potentiometer you need at RS. Pots don't have a current rating, they have a wattage rating and you need at least 2W pots, 5W would be a good choice. Possibly something like this: http://www.amazon.com/gp/aw/d/B002IABL6C If you find that you don't ever need to run...
  3. KJ6EAD

    Trying to understand AA batteries and their capacity

    Theoretically, yes, you can double the capacity by doubling the number of batteries in parallel. This will not alter the available voltage as would be the case if you added batteries in series. I said theoretically because there are some problems associated with putting batteries in parallel so...
  4. KJ6EAD

    Battery advice for LED project

    Yes, you can get 24V chargers. The 2A versions for wheelchairs are about $40. Look at the datasheet for the battery. It will show a derating curve to give you an idea of your capacity at an 8 hour rate. This is what Coca was referring to when he said you'd lose 25% off the top.
  5. KJ6EAD

    Battery advice for LED project

    Yes but they're very industrial. You can get separate small chargers much easier. You don't need to charge faster than 10 hours do you?
  6. KJ6EAD

    Battery advice for LED project

    You can buy the chargers and even the controllers easily enough. Were you intending to build your own?
  7. KJ6EAD

    Battery advice for LED project

    Yes, he later said those were figures for a 5m length so the actual numbers are 7.2W/m and 14.4W/m.
  8. KJ6EAD

    Battery advice for LED project

    It's not so much about measuring, although that may be part of the process, as deciding. If you look at the specifications for your LEDs you'll see that there's a wide range of current draw rates depending on which colors are being used. Are you running all 3 colors at all times or what? By...
  9. KJ6EAD

    Battery advice for LED project

    Are you sure those are W/m ratings and not mW/m? The higher voltage will be more efficient assuming you're using one of those segmented strips with the built-in limiting resistors. The higher voltage will also reduce your controller/driver current to half what it would be at 12V.
  10. KJ6EAD

    LED Component Question: Total Newb Here

    Those connectors do appear to have some kind of locking tab and glue. The glue can usually be defeated with a knife and the locking tab with a small screwdriver or spudger tool. I think it's more likely that the driver failed than the LED panel, but your swap test will determine one or the...
  11. KJ6EAD

    I want to make a battery pack that can make 7.5V at 3.0A.

    No, it only changes the voltage, not the amperage.
  12. KJ6EAD

    I want to make a battery pack that can make 7.5V at 3.0A.

    The discharge curve for alkaline D cells shows a 3A rate with a service life of 1 hour...
  13. KJ6EAD

    I want to make a battery pack that can make 7.5V at 3.0A.

    I would probably go with a 12V SLA (seaed lead acid) and a regulator.
  14. KJ6EAD

    Weird resistor

    In most applications, anything with the right inductance and of similar physical size should be adequate. Can you make any assumptions about current based on other connected components? If you look at the Hammond 2.5mH axial leaded inductors listed on Digikey, you'll see 3 current ratings...
  15. KJ6EAD

    Weird resistor

    It's probably a 2500μH 10% inductor.
  16. KJ6EAD

    Connector type

    It has a number on the top. It may have a manufacturer's name or logo somewhere. Have you looked?
  17. KJ6EAD

    Where to start

    Whatever you like really. The MiniKits are, as the name implies, usually smaller, simpler and cheaper than the others. You might choose one that you can actually use long term rather than one that you play with for a bit and set aside or you might choose one because it uses a particular type of...
  18. KJ6EAD

    Where to start

    The Nerdkits are good in that they have thorough documentation explaining the circuit theory but they're breadboard only, no soldering, so they lack permanence. Velleman kits are one of my favorites for overall quality but have minimal documentation. http://www.vellemanprojects.eu/products/
  19. KJ6EAD

    Where to start

    You might try some of the project books by Forrest Mims. http://www.forrestmims.com/
  20. KJ6EAD

    Ceramin Cap Label question

    The R would only apply if it were a resistor, and even then it's position would be wrong.
Top