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  1. J

    Current Mirror Help

    downloading zip files from strangers doesn't seem all that sensible. There is no other way to post your question?
  2. J

    Need help with this schematic!

    They are both transformers and it looks as if they are showing you how to hook up a center tapped transformer or a non-center tapped transformer. In the final design you would only use one way, not both.
  3. J

    Question regarding pass transistors

    Can someone here help me come up with a proper heat sink size for this circuit. The one like resqueline made? I finally got my mill working again and am ready to make my heat sink. I have a couple 5x5 inch chunks of extruded aluminum about 1/4 in. thick or so. I know this should be big enough...
  4. J

    Common Terms

    I actually see how they consider that, makes sense to me as I can see a frog laying there.
  5. J

    help with Joule thief please

    Another site says to try and use thinner wire if the circuit won't work. Maybe you could try that...
  6. J

    Question regarding pass transistors

    One more question. Can this type of circuit be built on prototype board or are the currents to much for the traces in prototyping board. One day I would like to try my hand at etching, but that would require me to learn how to do pcb prototyping software. Only one man, can't do everything at...
  7. J

    Pc Ram

    Check the bios. it will list the speed of the memory installed. It won't matter if you put faster memory in as it will all run to the lowest speed. If it has dual channel support then you will need to match your memory, but if you do not care about that then it really won't matter that much...
  8. J

    Voltage Regulator not regulating?

    yeah, it sounds like there is a short. Bad IC, something.
  9. J

    Voltage Regulator not regulating?

    When you mounted the VR to the heat sink you didn't create a short across the input/output did you? If you are not sure, remove the heat sink and test it for a few seconds. But without a load, it shouldn't be dissipating that much power being there is only about 10mA of ground current
  10. J

    electronic cirucuit analysis

    Well my first instinct is to simplify the schematic since V2 is doing nothing rendering that part of the circuit useless.
  11. J

    Solder Help!!!! PLEASE!!!

    Alright, it is clear that I have never really soldered because I am always getting bridging and sometimes it can be a real treat to get rid of those bridges. Those videos KJ linked to show some sweet technique. I take it the flux one uses has a lot to do with how well the solder comes out...
  12. J

    Question regarding pass transistors

    I just don't get what you are trying to tell me. I looked at page 18 and I do not see a schematic on that page that that uses a resistor in series with the output. As far as the switchmode schematics go, I am a little scared of those. I have never used, discussed, even experimented with...
  13. J

    Help with Laser Alarm Circuit

    Well I suppose if you discount the lack of convention used, there is nothing wrong with it. But that is why we have convention and why people who know, use convention to avoid confusion. Something a beginner should not be exposed too.
  14. J

    Question regarding pass transistors

    If I understand you, if you limit the current on Vout of the voltage regulator then you also control the current coming into Vin and also the base of the power transistors. But my only concern here is if I add in a resistor to limit current on the output then doesn't this also change my VR...
  15. J

    Question regarding pass transistors

    Yep that makes perfect sense, I should have known that. I still find it hard to analyse circuits because I am not always sure where I should start. I am gonna assume by a statement below that the 4.5A you use in the calculations below is what we want and is only an arbitrary number? I don't see...
  16. J

    Question regarding pass transistors

    correct, the higher the resistance the more voltage output you will get, so each time the switch is rotated from 3.3v to 24 volt another resistance is added in series. As we know resistors in series are additive. If you look resqueline changes the values(black text) of the resistors. These...
  17. J

    Question regarding pass transistors

    No, I think you got it. As the switch transitions from 3.3 to 24V the resistors will be added in series and be additive to the total resistance. No resistor will be in series to ground until the switch is rotated to that position. Take for instance R6, the only way to get to ground is by turning...
  18. J

    555 Timer, 556 Timer or Atmel micro

    LOL, I don't believe you and I think all the endangered and extinct creatures agree. Hope you solve your problem either way. I know we hunt coyotes around here and all I use is a call played through a very load speaker. If coyotes or foxes believe one of it's young in the pack is in danger...
  19. J

    Question regarding pass transistors

    Ok resqueline, I think I might have found an issue(possible in mine too since I drop 1.4V across R7, leaving me 26.5V to the LM317 input.) In your schematic R7 is a 22 Ohm resistor. I did the math and I see you are dropping ~2V across R7 with a current of 100mA. If that is the case then wouldn't...
  20. J

    Help with simple circuit

    Yes, that is how the meter works, by putting a load in series. They call this a sensing resistor and depending on the voltage drop across the Known load the current can be measured using ohms law AFAIK.
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