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  1. BobK

    Radio signal to AC power to DC

    Upping the voltage does not up the power. It is the power that is important when trying to use the energy. On the other hand, look up "energy havesting." This is a technology for capturing small amounts of power and then using them in a burst infrequently. For instance, you might gather...
  2. BobK

    TSQFP->DIL (kinda)

    Hey Steve, Did you do it a pin at a time, like the video you linked, or drag solder? Bob
  3. BobK

    Arduino control of model train signalling (was: LED Power Supply for Control Panel)

    For indicator LEDs the only "driver" needed to run them from 12V is resistor. It is somewhat wasteful, but at the low power that they draw, I don't see that as a problem. You can put your strips of 3 in series with one resistor and they will draw the same current as a single LED. It looks...
  4. BobK

    Switch mode LED driver...regulating I(in)

    Why would regulating the input current make a more stable output than regulating the output? The input current to a switch mode regulator is switched on and off (hence switch mode), so you can't really mean regulating it (i.e. keeping it constant). I think what you are talking about is...
  5. BobK

    Capacitors controlling attack and release of a pulse.

    First off, that is not a sine wave and is also not what a rectified audio signal will look like. Assuming you really want to shape a square pulse like that, I don't know any way you could do it with a passive circuit. Bob
  6. BobK

    Semi Newb Advice Request

    Oh! I didn't think you meant a kit for the whole thing. The first link seems to be a finished retail product, it is not clear you could do anything with it except look at it. You need the source code and ability to program it, which the second one seems to include. Bob
  7. BobK

    understanding an RC toy mainboard

    I was thinking that you could actually add on new driver transistors without modifying the board at all. You could use the two wires from the motor as signals to control the 4 transistors needed to make a full bridge. This could be a pretty safe way to do it without blowing out the existing...
  8. BobK

    SOIC>DIP

    You need either an adaptor or a PC board that you can solder it to. Bob
  9. BobK

    Semi Newb Advice Request

    Can you give me a link? Bob
  10. BobK

    understanding an RC toy mainboard

    The power transistors driving the motor are what are likely to need upgrading. Bob
  11. BobK

    Semi Newb Advice Request

    Don't know about AVR, but Micrcochip (PIC) has many DIP microcontrollers. You would need a programmer, the PICKit 2 or 3 is cheap and reliable. And the only solftware you need is free from Microchip (IDE, assembler, and C compilers) You can get either of the programmers with a demo board to...
  12. BobK

    BTech Project Ideas

    We could I, suppose, but it would be better if you considered: 1. What you already know. 2. What you would like to learn about. Bob
  13. BobK

    Protecting Vdd from anything over 5V?

    No, that is not what he is saying. He is saying you should add a low dropout regulator to reduce the voltage from 5V to 4.5V and hopefully suppress the spikes. What is the original power supply? Is it s regulated supply? Also, the 3.2ma current from the micro does not include any outputs...
  14. BobK

    understanding an RC toy mainboard

    Depending on the board, there might be 4 bipolor transistors or MOSFETs, or there might be one or two chips that contain other circuits as well as these transistors. Look at where the motor wires do on the board. They will be connected to the transistors or chips that supply the current to...
  15. BobK

    Testing Volts and Amps in my Circuit

    Bob again, doing tag team with Steve :) The characteristic Vf in an LED datasheet is only the typical value. Often they give minimum and maximum values as well, indicating a range of voltages at which the voltage might be the stated current. This is due to the variation from one device to...
  16. BobK

    LED Controller

    A microcontroller running fast enough and programmed in C or asm should be able to manage 24 soft PWM outputs. That is the way I would go, with a MOSFET for each of the 24 signals to handle up to 3A (choose one rated at 5 or more). If you use MOSFETs with very low on resistance you might...
  17. BobK

    Voltage Multiplier Design

    Voltage multiliers and boost regulators are both for creating higher voltage power supplies from lower voltages. Neither is well suited to what you want to do, which is to boost a signal by a specified ratio. That is exactly what an amplifier does. In answer to you new question: Look up...
  18. BobK

    Engineering Student in Need of Data

    On your question about which methods you use, you should allow multiple selection. I have used most of those listed. Bob
  19. BobK

    SMD Soldering

    vitroblue, I used your method until I found paste solder. Paste solder is much easier, for me anyway. Bob
  20. BobK

    understanding an RC toy mainboard

    Also note that going from a 600maH NiCd to a 2000 maH NiMH might even make it ruin slower! NiMH is not as good as NiCd at high current draws. Given the higher capacity, it probably will run the same or better, but if the capacity of the two batteries was the same, the NiCd would most likely...
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