Search results

  1. E

    All about antennas

    get a good grasp of what antenna is, the types out there, the differences between them. it will help you understand why people build antenna and use different antennas in different application as well as drawbacks. once you understand this, it will make more sense to build one.
  2. E

    Where to find tool sets?

    radioschack. they have some kronus tool sets for like $15/$20
  3. E

    Voltage of an inductor

    How do you find voltage drop produce by the coil/inductor? I know V = L(DeltaI/DeltaT), so if i have 1A flowing and 2mH at 100kHz, does that mean i can generate drop upto 200Vp-p?
  4. E

    Does this exist (proximity circuit)?

    there are 3 types of rfid, passive, semi-active and active. Passive rfid harvest the energy from the coil so it only works when it is close to detect the energy (inches). You will need active rfid. Try digikey. there's a reader from atmel u2270B, add that with a controller and a tag to read.
  5. E

    Understanding the capacitor deeply

    yes, thanks for correcting me
  6. E

    Understanding the capacitor deeply

    capacitance has inductance as well. its generally Ceff = C + L//C or some other combination. As frequency increases, impedance drops, and once it gets beyond a point where inductance is dominant over capacitance, impedance goes up.
  7. E

    CMOS driving TTL? fanout question

    ok, so mainly the difference is voltage level, and as long you meet the requirements to toggle the gate it should work. One more thing, aren't all chips these days made CMOS, because its lower power consumption than TTL? How do i know if a chip is TTL or when to use 'T' type package?
  8. E

    CMOS driving TTL? fanout question

    Berkeman, what is the main difference between ttl compatible and cmos compatible? A 'non t' part has the conventional cmos input threshold, while ones with 't' has both cmos and ttl compatibility. Does that mean if i use a 't' part it wont drive a 'non t' part? I thought as long as it meets the...
  9. E

    How to work out the turn ratio on a transformer

    http://en.wikipedia.org/wiki/Transformer
  10. E

    How to work out the turn ratio on a transformer

    its based on the ratio as stated
  11. E

    Capacitance of parallet plate with dielectric spheres in between

    capacitance in parallel is same as resistor in series and vice versa. c = permittivity*dielectric*area/distance If you have a sphere, it will be an integration of series of capacitance depending on the diameter of the sphere at different location. At the tip of the sphere, the dielectric...
  12. E

    What does In equal?

    the electrician already explained. its called natural log. In your calculator natural log. Its not 'In', the symbol is Ln, or some people write L as 'l', and unfortunately 'l' looks like 'I' http://en.wikipedia.org/wiki/Natural_logarithm
  13. E

    Square Wave Generator

    i was going to suggest DDS but doubt there's any chip out there to work with
  14. E

    A question on norton method

    delete It would be best if you draw a simple circuit, with voltage and 1 resistor. What is the current? What happens if you add 2 resistor in series now. What is the current and voltage between both resistor. Keep adding, another resistor in parallel with 2 resistor in series and find...
  15. E

    A question on norton method

    you can make current go any way you want as long as you stick to the same convention throughout the circuit (this is just something to keep in mind) In this case, you have 3 lines in your circuit with respect to that node. Current is not pointing up. That is just a symbol for current. It says...
  16. E

    A question on norton method

    current in = current out I (current into node) = (e-v)/R1 + e/R2 (current out of node)
  17. E

    Whats the common name of this course

    http://www.ocwconsortium.org/index.php?option=com_content&task=view&id=12&Itemid=26 go to their courseware website and look through their EE stuff. Hope this helps
  18. E

    How do you create best fit line?

    thanks for the explanation and the link. will look into it
  19. E

    How do you create best fit line?

    Like the title says, if you have a bunch of data you can create a best fit line For example back in school, for a linear line, y = mx + c, you just need 2 points to get a line. But what if you have more than 2 points, say 10, what is the best fit line equation or how do you do it...
  20. E

    Current/voltage leading and lagging

    https://www.physicsforums.com/showthread.php?t=52304
  21. E

    8:1 Mux Pin Diagram

    here's a 8:1 mux chip http://focus.ti.com/lit/ds/sdls054/sdls054.pdf
  22. E

    Op-Amp Gain

    http://www.google.com/search?hl=en&q=LM741+MA741&btnG=Google+Search
  23. E

    Autofocusing system for Control Systems Project determining defocus

    what are the main differences between both figures? Did you change the distance from your camera to the object?
  24. E

    Autofocusing system for Control Systems Project determining defocus

    images on checkboard like black-white-black-white-black-white..... are you changing the size of the sequence image on the checkboard? or when you say focus image then the center looks focus and the sides look a bit blur? If you could post some image it would help
  25. E

    Should I go to the doctor

    lol its not RoHs compliant chip? how many pins did you stab yourself with? chances are we absorbed more lead in food/solder smoke, paint
  26. E

    Difference in index refraction

    What does a higher index of refraction really mean? I know about speed wavelength etc but lets say you have 2 different material to choose and ignoring other variables, and focal length, diameter are all the same between both material, would you choose a lower index refraction or higher. Thanks
  27. E

    Autofocusing system for Control Systems Project determining defocus

    do you have multiple element lens and moving the distance of 1 lens to change the focal length? This may be helpful. Check the resolution of the pixels, FOV of interest etc http://www.edmundoptics.com/TechSupport/DisplayArticle.cfm?articleid=288 [Broken]
  28. E

    Spot size and focal length lens

    why does the spot size increase with lower f#. Lets says you have 2 lens of the same material, and diameter, just different focal length. F/2 has higher spot size than F/3 but F/2 is faster. Is spot size a characteristic of a lens? So if your detector is fixed in size you need to get a lens...
  29. E

    Frequency Addition

    would a mixer work? it will return F1-F2 and F1+F2 put a high pass filter to get rid of the lower frequency
  30. E

    How do you make a circuit board work ?

    it would be cheaper to just buy a desktop. check the de11 outlet. You have to know what you want to do, what you need and work it out from there. Microprocessor, signal/data lines etc
Top