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  1. J

    LDR Motor Circuit

    the way you have it hooked up, the lower the pot. resistance the more the transistor should turn off
  2. J

    where did resqueline go?

    The title says it all. been a while since he posted.
  3. J

    Proximity alert wildlife watch

    http://www.pic-tronics.com/How-to-make-a-wireless-spy-camera.php Maybe something like this will peak your interest. Though I have never worked with the xbee I have always read good things about it. Really simplifies the process of making a wireless network. Not sure it can do video, but if you...
  4. J

    Simple circuit advice

    I am not sure I understand your concern.
  5. J

    What will happen if point A short with ground

    Neither transistor will conduct with zero base current. Think about what harald said again.
  6. J

    Problems building first circuit - capacitor ESR meter

    This doesn't really make any sense, the 820Ohm resistor should have nothing to do with the function of the 555 in this circuit. The 555 has and will always be in this circuit running in astable mode.
  7. J

    Just throwing out an idea......

    Yeah, ask NASA!!! :D
  8. J

    Problems building first circuit - capacitor ESR meter

    From the description on the website of how it works I would say you want the 555 to run in astable mode. active low means that when the signal on pin 4 is low the reset function is active. This keeps the 555 from working. Anyway, someone else will have to help you out further. The way that...
  9. J

    Problems building first circuit - capacitor ESR meter

    Pin 4 is the 555's reset and it is active low.
  10. J

    Problems building first circuit - capacitor ESR meter

    Ok, well if you want help you will need to fix the link to the schematic and also link to the real photos and not the thumbnails. As a start I would connect pin4 to Vcc, so you can at least eliminate that issue.
  11. J

    Experiment 9; MAKE: Electronics

    As davenn has said, take a look at this picture again. The problem is with the resistor side of the circuit. The photo above looks nothing like the diagram in your book!!! We already showed you a picture of how the breadboard is electrically connected. So fix the switch and resistor according to...
  12. J

    LDR Motor Circuit

    so disconnect the motor and see what happens to the transistor. then while your at it, measure the voltages.
  13. J

    Trying to fix Black and Decker RT650 multitool

    another broken rectifier. That is like what, 3, this month?
  14. J

    Need help with strobe circuit

    I wonder if a pull-down resistor on pin3 of timer1 will have any effect. Say a high value like 10k What happens if you remove timer2 completely? does timer1 work as designed?
  15. J

    Need help with strobe circuit

    Did you try building this circuit on a breadboard first? One thing that was mentioned and you still have wrong on the pcb is the possible short from pin8 to pin7 of the first timer when the 1k pot. is 0ohms. The 1k pot. should be in series with the 120Ohm resistor. I also don't see the ground...
  16. J

    Experiment 9; MAKE: Electronics

    this is gonna sound so cliche, but 'patience is a virtue!'
  17. J

    Experiment 9; MAKE: Electronics

    I remember on the last experiment you didn't figure it out and yet you said, "I just want to move on." The problem with that, you are starting to see. The book is trying to build your knowledge, if you skip past a section and fail to understand it then I don't see how you can expect to...
  18. J

    Checking a capacitor

    I am sure you searched on google first, right? if it is a significantly large capacitor, you might be able to use your meters ohm setting. Knowing that a capacitor is a short when the voltage across it is zero. Remember that on an analog meter the polarity is reversed for the leads in the ohm...
  19. J

    Overheating resistor??

    it is easy, with a 3V drop LED then you can only have one LED in series for a 5V supply. 5V - 3V = 2V drop across the resistor. 2V/20mA = 100 Ohm resistor
  20. J

    Wanted: PIC programmer.

    I am actually looking for the hardware programmer so I can do serial programming.
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