Search results

Search Forums New Posts
  1. BobK

    Help for a newbie? Dividing DC power

    3 separate DC to DC converters would do it. The is no way to equally split a voltage like you want to unless the loads are always on and all take the same current, in which case they could be wired in series. Bob
  2. BobK

    How to Switch Voltge Sources

    If connected the way I said, it is still going through the same 5V regulator as the 12V supply. Bob
  3. BobK

    Need some advice on an LED project

    You cannot connect two lamps in parallel to a constant current driver. There is no guarantee that they will share the current equally. And worse yet, when one gets more current than the other, it heats up more, which, for LEDs causes it to take still more current until it is destroyed. Bob
  4. BobK

    How to Switch Voltge Sources

    Only connected through a reverse biased diode. I was not addressing charging. Bob
  5. BobK

    How to Switch Voltge Sources

    Okay, just connect the battery + to the + output of the bridge rectifier through a diode (anode to the battery +) This will make the battery take over whenever the power supply is off, and there will be no drain on the battery when the power is on. Battery minus should - to the - output of the...
  6. BobK

    Circuit power help?

    If you have a number for it, look it up. Otherwise, connect it to a variable power supply and ramp up the voltage until it gets to the desired brightness. Then measure the current at that voltage. Edit: Oh, and welcome to the forum! Bob
  7. BobK

    How to Switch Voltge Sources

    Is this something you built yourself? I cannot imagine why anyone would use a 12.6V transformer to power something at 5V. Bob
  8. BobK

    Help with simple circuit

    Huh? I find Arduino nano's with USB for as little as 2 bucks on Ebay. Why use one that needs a programmer? Bob
  9. BobK

    12vac to 12 vdc - blackhole

    A buck converter can convert down to any voltage lower than the input. There may be a dropout voltage, i.e. it may need say 1V more than the output to operate, while some can operate all the way up to the input. Bob
  10. BobK

    Component question - Pivoting robot arm?

    Lifting 55 pounds at 1 foot per second would take 1/10 of a Horsepower or 75W. Allowing for electrical and mechanical losses, it would take about 150W motor to do this. So we are not talking about servos or small stepper motors. Bob
  11. BobK

    Shift register HC164 sensitivity issue

    I can't see anything wrong with that unless the GPIO driving the A and B inputs or CLK is set to input sometimes. Bob
  12. BobK

    Attaching one-wire sensors to max/min thermometers - total newbie, sorry

    Not likely unless the unit uses the same protocol (1-wire) and data format. If you can find someone who can build microcontroller projects, it would not be difficult to make one that read the probe and kept min and max temps. Bob
  13. BobK

    Help for a newbie? Dividing DC power

    It is not clear at all what you did. Please explain further with a schematic if possible. Oh, and no, there is no simple way to make a 36V source into 3 12V sources. However, you could draw 12V from one of the 3 12V batteries that make up the 36V power supply. Bob
  14. BobK

    Have you ever gotten "lucky?" (when repairing electronics)

    I opened up my guitar amp when it stopped working, no output. There was a socketed TL082. I happened to have one on hand, so I replaced it and bingo, I had a guitar amp again! Bob
  15. BobK

    using microcontroller as current generator load

    See here for what current loops are used: http://en.wikipedia.org/wiki/Current_loop Bob
  16. BobK

    Component question - Pivoting robot arm?

    50 pounds? Really? How much does the robot weigh? Bob
  17. BobK

    Project for the diasbled

    How about a remote alarm when there is undue force on a bed railing? My 90 year old father-in-law, who was delirious from a new drug he received, managed to break through the railing of his bed and we found him on the floor in the morning. Miraculously, he was unhurt. Bob
  18. BobK

    Noobie question - battery life

    In other words, 8 2000maH 1.5V batteries in series make a 2000mAH 12V battery. Bob
  19. BobK

    pic16f722a clarification

    You cannot use the pin used for Vcap for anything else. It will have a fixed voltage of 3.2V on it. Also, 0.01uF is not between 0.1uF and 1uF, the range needed for Vcap. Bob
  20. BobK

    Rest in Peace, Kris

    In addition to his amazing level of knowledge, Kris's patience and willingness to help were an inspiration to us all. The world has lost a very good man. Bob
View older results
Top