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  1. J

    Question regarding pass transistors

    Yes, but as resqueline stated before, it is better then not having a resistance there or the output voltage will be close to the input voltage.
  2. J

    Help with Laser Alarm Circuit

    Plague, I was just like you when I first started out. I had even looked at this schematic, but as poor mystic has stated. It is a poor example of a schematic if I have ever seen one. This is where I started. Note: the link in the first post of this thread used to point to a video with the same...
  3. J

    Question regarding pass transistors

    My whole goal was to build something that would be useful and hopefully let me move from theory to reality so that I can start to understand the concepts behind finished designs and their limitations. That is why my first post was simply, "What are the advantages and disadvantages to the two...
  4. J

    Question regarding pass transistors

    Ok, so then that schematic is wrong in just about every way? If I understand you correctly, this schematic, the first one http://talkingelectronics.com/projects/200TrCcts/101-200TrCcts.html#58 Because if what your saying is correct, then there is no way for there to be a regulated voltage at...
  5. J

    Question regarding pass transistors

    I am still not sure how that answers my question? I am not trying to be rude, but all I want to know is what is max voltage one can apply to the base-emitter junction and why is this info not in the datasheet? edit, I am not curious about the voltage drop across the junction. I want to know if...
  6. J

    Question regarding pass transistors

    Yeah I kinda figured that out finally. But what is the max voltage one can apply to the base before it breaks down, like the Vce voltage listed in the datasheet? They list the Vce as 70V before the transistor will fail. There has to be an equivalent Vbe, right?
  7. J

    Help with simple circuit

    Gremonk, what you have to understand is how much power the battery can realistically store. Also, depending on the internal resistance of the battery it can only create just so much power. Resistance is viable no matter where it is located. Take a resistance measure of the battery just to prove...
  8. J

    Best way to ac power in wilderness w/out gen

    How long do you sleep? 8 - 10 hours? Hook up another battery in parallel with your car battery and you will double the capacity. I believe a alternator is over built for a car so I don't think charging another battery should be that difficult. Just make sure you wake up before you run the...
  9. J

    Boeing 747 Fan blades

    Look up a website named Windy nation. They are all about wind turbines and probably more in tune with all things wind turbines. :) http://www.windynation.com/community/
  10. J

    Transistors

    Base-emitter junction is typically 0.7V for a silicon based transistor. Transistor DC gain is 'HFE' found in the datasheet(I looked, it is anywhere from 40 to 75 based on Ic, it is always best to use the low number which gives you some extra breathing room). The base voltage is what your circuit...
  11. J

    Transistors

    What is your required current? Divide this by the HFE (transistor DC gain) and you will know your base current. If you know the base voltage, you should just be able to use Ohms law to figure the resistor needed to provide the current. Don't forget, you will need to make sure the transistor is...
  12. J

    Question regarding pass transistors

    On second thought, is the Veb rating in the datasheet the reverse breakdown voltage of the e-b junction? If that is the case then what would the max b-e voltage be?
  13. J

    Question regarding pass transistors

    Yes davelectronic, but even in those stats you provided, the base-emitter Voltage is max of 7V. If I was to build a circuit like the one I posted using the TIP3055 as the only pass transistor, then the Regulated voltage would have to be the TIP3055 base voltage minus the voltage drop across the...
  14. J

    Help with simple circuit

    davelectronic, I got an issue with that pie chart. How in the hell can IxR=V and the square root of IxR=V, Both of those would need to be equivalent, and that is not possible.
  15. J

    Help with simple circuit

    wait, You are saying that when nothing is attached to the battery and you put the meter on the battery to get a amp reading the meter says 2.5A? Since I am not the brightest crayon in the box, this might be wrong, but you can not create power where there is no power! In other words, if the...
  16. J

    Adding lights to lawn tractor

    Or you could buy two new exact same lights as are already on the tractor, mount one behind the lawn mower and one on top of the blower. Then have a switch that will cut off the two original lights that would be blocked by the blower anyway and use the power that would be available to them to...
  17. J

    Question regarding pass transistors

    My regulated voltage would be the Vbe - 0.7, now the question is what is the max Vbe for the 3055 and what Ib would I need to get say ~10A? edit: After looking up the MJE3055, the Vbe is only 5V.That doesn't seem like it would work out to well for a PSU with a select-able V range of 3.3. to...
  18. J

    Help with simple circuit

    0.8A == 800mA 0.08A == 80ma So unless you wrote that wrong, you are still not getting the correct reading.
  19. J

    LM317 as current regulator

    they are not using the LM317 as it was intentionally designed for. They are using it at its minimum output voltage to regulate current through a LED.
  20. J

    Reusing a shattered Solar Panel

    with water proof silicone and the screws.
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