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  1. BobK

    Using all four amplifiers in an LM324

    Hey, I am an expert at typos. :)
  2. BobK

    noob here.... can i use a generator to power my electric motor (woo woo)

    Do you really think you are the first person to think of spinning a generator with a motor and powering the motor off the generator? Really? Hint: I thought of when I was about 8. It did not work for me then, it did not work for the millions of others who have thought of it. And, after...
  3. BobK

    Back lit Chess Board, Led Question

    We wait with bated breath! Seriously, though, I would like to see pictures when complete you it. Bob
  4. BobK

    Need help with a proof of concept prototype.

    Another great thing about beards is that they can be used to create a system of measurement units: From Wikipedia: Bob
  5. BobK

    IR Sensor

    I doubt that. If your photodiode cannot pull a 3K resistor close to ground, it certainly cannot pull a 220Ω resistor to near ground. If it is working, you have a phototransistor, not a photodiode. Bob
  6. BobK

    Using all four amplifiers in an LM324

    The LM386 is a power amplifier designed to drive a speaker. The LM324 is a quad operational amplifier. You would not use the LM386 as an operational amplifier. You would not use an LM324 to drive a speaker. Each opamp in an LM324 is capable of high ampliciation, it is typically unnecessary to...
  7. BobK

    NMOS Reverse Polarity Protection

    Okay, I have looked for a circuit and found this: http://www.ti.com/lit/an/slva139/slva139.pdf The MOSFET is being put in backwards from it's usual usage, i.e. with an N-MOSFET the drain is connected to the battery - and the source to the load. Normally, you would not do this because the body...
  8. BobK

    Project 1 : Battery pack / charger

    I thought you were trying to charge batteries from a solar cell. Bob
  9. BobK

    Voltage Regulator Question

    And the capacity is way less at higher currents. The Alkaline that is listed at 565maH in Gryd3's table is less than 300mA hour when discharged at 500mA. Bob
  10. BobK

    Voltage Regulator Question

    If you are planning on using the standard rectangular 9V battery, it will have enough energy for less then 1 charge, and you will waste nearly half of that in the regulator. Bob
  11. My Wearable Device

    My Wearable Device

    Just in time for Christmas. A 10 pointed star with green LEDs and red LEDs on alternating points. Run by a PIC16F1517 44-pin microcontroller. All surface mount 0805 LEDs and resistors and the TQFP PIC. 700 lines of C code. Two-sided boards made by Osh Park (the descendant of BatchPCB), 3...
  12. BobK

    My Wearable Device

    BobK submitted a new Showcase Item: My Wearable Device Read more about this showcase item here...
  13. BobK

    NMOS Reverse Polarity Protection

    Show us the circuit. Bob
  14. BobK

    Project 1 : Battery pack / charger

    Okay, good. I thought you were going to try to charge them without the IC. You would need 1 controller for each cell. There are many single cell LIPO charger ICs out there. Bob
  15. BobK

    Best places to get supplies?

    Have you tried Digikey and Mouser. They are the biggest electronics suppliers in the U,.S. Bob
  16. BobK

    Voltage Regulator Question

    What is the power source? You will need at least 7V to get 5V out. Bob
  17. BobK

    Looking for a better understanding of ground loop noise

    I used on from Radio Shack to fix the hum when connecting my desktop to my stereo. Bob
  18. BobK

    IR Sensor

    Yes, a photodiode cannot pass enough current to pull a 3K resistor low. What are the specifications of the photodiode? You will need to amplify the signal or use a phototransistor, which has the amplification built in. Bob
  19. BobK

    Back lit Chess Board, Led Question

    I think you need to use diffused LEDs, and probably a lot more than 9 in order to get reasonably uniform illumination. bob
  20. BobK

    What to consider when making a 6/8/10 way mains extension

    1. Switching an SSR at a rate of once every 10 minutes (or once every minute) is not going to cause a heating problem as long as the SSR is operated within it's specifications. 2. I don't think those are SSRs on the link you posted, I think they are relays. Bob
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