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  1. BobK

    Basic cable/wire

    This is presumably a signal, which does not carry much current at all, so just about any wire would do. Pretty much all wire is copper wire. Bob
  2. BobK

    Basic cable/wire

    Not sure what you are asking then. You already have the source for the pins, which are the only thing you need to match to something else. Pretty much any wire and switch would do. Bob
  3. BobK

    Low side switch

    I don't think 11 Amps worth of light bulbs would destroy a MOSFET rated for 80A continuous. You do make a good point about the gate voltage though. You would need a level shifter to use this from a micro. Bob
  4. BobK

    Basic cable/wire

    Let's see what might be possible reasons: 1. It will harm the engine. 2. It will violate emissions standards. 3. ? Additional reason why you might not want to do this: If the computer logs that fact that it has gone into this mode, you might invalidate your warranty. I wouldn't mess with...
  5. BobK

    Low side switch

    Use automotive (12V) bulbs. Two in series should be fine with 30V since they actually operate at 14V+ in a car. Use as many strings of 2 in parallel to take 11A. And you better have a massive heat sink for that transistor and probably a fan. 11A at 0.3Ω is 36.3W. If it is your intention to...
  6. BobK

    Decoding PWM

    On rereading, I think you are right. Much more complicated now. Only a microcontroller would make it easy. Bob
  7. BobK

    A device that creates the effect of slow motion.

    Interesting effect. I believe it works like this: You vibrate something at a given frequency, let's say 100 Hz, i.e. 10ms period. The you strobe it at say an 11ms period. Each strobe then has shown it advanced 1/10 of an period, so it looks like motion at 1/11 the speed. Bob
  8. BobK

    Decoding PWM

    Alec, He is not trying to control the speed, just the direction via a remote that is intended to drive a servo. Simply running forward if the pulse width is > 1.5 and backward if < 1.5 and stopped if nearly 1.5. What you need is an integrator and a window comparator. On the falling edge of...
  9. BobK

    Logic behind resistor values

    Another way of looking at it is to consider how you might make 5 resistors in the range of 10 to 100 Ohms. It would seem like you should 10, 20, 40, 60, 80, 100 But then the ratio between the first two resistors, 1:2 is huge compared to ratio between the last two, 4:5. The E series make each...
  10. BobK

    Ethernet transformers from Mouser -- awesome service

    Just looked up some prices. Pickit 3: USD 47.95 AUD 67.85 which would be 52.25 USD So they are charging you a bit more, then giving you free shipping. Probably good marketing since everyone hates paying as much for shipping as they pay for the merchandise. Bob
  11. BobK

    Basic Electronics

    Which, in the example of 1MΩ, would be make the voltage 5.996V, or 6V to 3 digit accuracy. And the input current ot the ADC is probably even less than that in reality. Bob
  12. BobK

    Ethernet transformers from Mouser -- awesome service

    I looked at the website again, and there does not seem to be free shipping in the U.S. Very strange. I wonder if their prices are higher for overseas shipments. Bob
  13. BobK

    Transformer - Number of turns?

    You would use fewer turns to convert a 220:110 transformer to 220:30, not more turns. Bob
  14. BobK

    Basic Electronics

    6V. The ADC inputs of the pull so little current than even with 10K impedance the voltage drop will be less then the resolution of the ADC. So with only 572Ω, the drop will not be measurable on an ordinary multimeter. Bob
  15. BobK

    Need Help With Li Ion Battery

    Your best bet would be to use a power bank, which contains a lithium ion battery, and charging and protections circuits already built in. And they are for sale for cheaper than you could make the equivalent. The key to sizing it is Watt Hours. A battery pack is rated in Amp hour, or more...
  16. BobK

    "Simple" light sensitive, Servo Project

    You will have to clarify what you mean by "run a servo off a photoresistor" A servo requires a constant series of pulses whose width determines the position of the servo. Do you mean that the position of the servo should be controlled by the amount of light falling on the photoresistor? Bob
  17. BobK

    Ethernet transformers from Mouser -- awesome service

    Hmm. I use Mouser for most of my parts orders and they always charge me shipping. I guess it helps to be overseas! I do have to say that they are very good. For parts in stock they ship on the same day and by U.S. post I get it in 2 days typically. Bob
  18. BobK

    How to get 3.3 V from a charged LiPo battery?

    You can find low dropout regulators that will drop a couple of hundred millivolts. Or you can use a buck converter. Bob
  19. BobK

    Battery advice for size and weight sensitive project

    No, you didn't. But if you want the smallest battery you can get, you would want one that lasts no longer than necessary. Also, the fan will not run directly off a LiIon battery. You would need a boost converter as well. What kind of size are you talking about? I think you might have boxed...
  20. BobK

    Battery advice for size and weight sensitive project

    Well, as you found, button cells are not designed for 40mA. Most primary batteries, in fact, are not designed to discharge over 1 hour or less. A lIthium Ion battery (like in a cell phone) would be the best bet. You can get industrial ones in practically any shape and size, and, of course...
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