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  1. Hero999

    resistors

    I'm not sure what you're asking. I calculated the values of 0.5R and 0.75R using the potential divider formula: http://en.wikipedia.org/wiki/Potential_divider#Resistive_divider_2 R1 = series resistor. R2 = 3.2R the heating element. VOUT = 4.5V or 4.2V the voltage across the heating element...
  2. Hero999

    resistors

    No 0.76 Ohm is 76 Ohm divided by 100. You need to round to standard values as audioguru told you. RadioShack are expensive and only stock a limited range of components, go to a real component supplier such as DigiKey. The resistance probably won't change much when the voltage is reduced...
  3. Hero999

    Electric Fence Indicator/Display.

    If the fence is unloaded the current will be tiny. The only current flowing will be due to the leakage resistance, corona discharge and charging/discharging the fence's capacitance. The current should be much higher near the energiser than further away from it and will actually increase when a...
  4. Hero999

    resistors

    You need to provide more information. Why are you reducing the voltage? If it's a motor or light bulb then you'll be fine. If it's something like a radio and want to reduce the volume it's not a good idea because it will probably not work properly with a resistor connected in series.
  5. Hero999

    MOSFET VGS

    Keven, Why do you keep making nonsensical statements? If you want to ask a question, ask one. If you want confirmation as to whether a statement you've made is true or not, end the sentence with a question mark. That makes no sense, a MOSFET doesn't have an emitter. That doesn't make any sense...
  6. Hero999

    MOSFET VGS

    It depends on what you mean by low or high voltage? Technically low voltage is any voltage below 1.5kVDC or 1kVAC which is much higher than the voltage rating of a typical MOSFET. The short answer is the gate voltage must be high enough to ensure the MOSFET can pass the required drain current.
  7. Hero999

    Light bulbs

    Thanks, I assume that those graphs can be scaled for different bulbs, with other power ratings.
  8. Hero999

    Electric Fence Indicator/Display.

    I'm not sure if the current transformer idea would work as the current will be very low. What you'll probably find is that if you wind the turns around the fence and connect one side of the neon to it and the other to earth, it will light due to capacitive coupling, assuming the insulation on...
  9. Hero999

    Electric Fence Indicator/Display.

    Resistors with voltage ratings of 10kV and up are available. The break down voltage is listed on the datasheet as 90V to 135V but will vary widely depending on the age of the lamp, the temperature and ambient radiation levels, yes electromagnetic radiation can actually lower the breakdown...
  10. Hero999

    Thesis Topic

    What topics did you suggest and why were they rejected?
  11. Hero999

    SMD resistors and capacitors Package

    The package size can be found on the datasheet. A list of common dimensions can be found on wikipedia. http://en.wikipedia.org/wiki/Surface-mount_technology#Package_sizes
  12. Hero999

    Equivalent Circuit For Solar Cell Solarex MSX 005F Pilot Cell CPC1824 For Simula

    I'm not sure what you're asking. It's not possible to accurately simulate a solar cell and nor is it necessary most of the time. A solar cell looks like a diode with a constant current source connected in parallel with a couple of resistors. You should be able to get the value of RS + RP...
  13. Hero999

    2V high current power supply for homopolar motor

    2V is an odd voltage, you'd be better off finding something that will give 3.3V and modifying it for 2V but that won't be easy either. You're right, building a 12V to 2V high c urrent DC-DC converter is not easy.
  14. Hero999

    Detecting air flow

    There are plenty of ways to do this, hot wire is probably the best but needs to be compensated to the ambient temperature.
  15. Hero999

    Solar and Batteries and LED's questions

    The forward voltage of the LEDs decreases as they warm up causing them to draw more current, unless you use a regulated constant current source. Try measuring the voltage across the LEDs. In future please upload pictures as attachments here rather than on another site.
  16. Hero999

    Light bulbs

    What's the purpose of this thread? Are you asking a question or making a statement? An incandescent light bulb is nearly purely resistive and has virtually no reactance so will have a power factor near 1. The resistance of the filament varies with temperature which is also dependant on the...
  17. Hero999

    TIP142 Stepper motor driver

    That's not the complete circuit, it doesn't show what's driving the transistors.
  18. Hero999

    Camera flash style circuit - need a little guidance

    To be honest I'm still not sure what you want help with. Do you already have a circuit to light the LEDs but just need a timer? A 555 timer will do, the schematic is on the datasheet which can be found using your favourite search engine. :D As far as a circuit to light the LEDs is concerned...
  19. Hero999

    TIP142 Stepper motor driver

    There's no need for a variable resistor. You could have destroyed the controller output by setting it to too lower value. Use 220R, as I said in my previous post. I would help you to troubleshoot the circuit if you post the whole circuit rather than just part of it.
  20. Hero999

    simulating LTC3401 and or LT1307

    Have you checked to see if you can import the LTSpice libraries to Orcad or Miltisum? Why can't you simulate the whole thing in LTSpice? What is your project? It's probably not worth simulating the whole thing anyway and simulating it all at the same time is normally pointless.
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