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  1. shekhar_dandya

    Cutoff frequency and 3dB points

    Hi All, I may not be 100% correct,but,a loss of 3db in gain does not hamper the overall response of the amplifier.i.e this loss is unnoticable in the o/p of amplifier.But we get higher bandwidth at peak- 3db gain,compared to bandwidth obtained considering only the flat portion of the...
  2. shekhar_dandya

    Set up time and Hold time

    Hi Shiva, The set up and hold requirements stem from the fact that if 2 logic signals change simultenously at the input of a digital sequential circuit there is a possiblity of metastability.Which physical phenomenon is responsible for that I still don't know,if anybody on the forum knows,I will...
  3. shekhar_dandya

    Understanding test conditions in any Datasheet

    I went through the pdf.It definitely helped me. comming back to the question, So should I take these "test conditions" in my design and calculate other parameters of my circuit?
  4. shekhar_dandya

    Understanding test conditions in any Datasheet

    Hi H.W.Wizard, I did not get you. ???Can you be more elaborate?
  5. shekhar_dandya

    Understanding test conditions in any Datasheet

    Generally all parameters of a device in any datasheet are specified at certain test conditions. my question is : 1) How are these test conditions chosen?what criteria? 2)What is their importance? 3) What values of parameters should we select if these test conditions do not exsist in our circuit?
  6. shekhar_dandya

    Basic Transistor Circuits questions

    But How does one decide Q point Ic i.e dc Ic?I find many students assuming Ic of 1 mA,just because its fairly a reasonable value. So,when to use say,Ic of 1mA when to use Ic of 10mA or 100mA?
  7. shekhar_dandya

    Basic Transistor Circuits questions

    While designing a transistorised circuit,say a voltage divider bias,an amplifier etc,should we select the transistor first and then decide the Q-point characterstics based on its datasheet or we establish the q-point characterstics and then select a suitable transistor? If condition2 is...
  8. shekhar_dandya

    when should use FPGA?

    Ante, If this is meant to be only for MCU's then plz create a forum for
  9. shekhar_dandya

    How to make RPM counters

    This method will work for slower RPM, for faster ones? I think then one can measure no. of revs in say 10 sec and then calculate for 1 min? what do you say?
  10. shekhar_dandya

    How to make RPM counters

    How to make an RPM counter? Assuming you have some sensing mechanism,say a flywheel with a slit to pass the light beam that is sensed by a photosensor at reciever end and which is attached to a transistor driver  that gives you square pulses for every cut. How to process the rest of the signal...
  11. shekhar_dandya

    'potential Difference' questions

    So,motion of electrons constitute current.Hence its current that creates "potential Difference",right?or is it that "potential difference" causes current?Is this that-first egg or chicken problem? BTW I still don't understand the basic origin of Energy in a battery,exactly which chemical energy...
  12. shekhar_dandya

    'potential Difference' questions

    If voltage is potential Energy difference,where does this potential energy come from in batteries or cells?If the answer is "chemical reactions" then which chemical reactions/physical phenomenon(bonding,thermodynamics?) is responsible to impart this "potential energy" to electrons?
  13. shekhar_dandya

    International Physics olympiad problem

    solve this international olympiad prob suppose a cylinder of weight 20N is rolling on ground in right direction.if half of length of cylinder is positively charged,and it is placed in magnetic field whose dirction is inward to plane of rolling and if a charged particle is placed at distance 10m...
  14. shekhar_dandya

    Voltage

    "Potential" of a point in space,as I was taught in school, is energy spent in bringing a charge from infinity to that point within the vicinity of test charge,which is exerting the force on our charge. So energy spent is stored as
  15. shekhar_dandya

    Simulation Models Creation...

    Try downloading Labcenter electronics evaluation version Proteus software from their website.It internally uses PSpice.I foud it very handy for microcontroller based simulations...hope you will also find it useful.
  16. shekhar_dandya

    USB for Real time applications?

    Has anyone tried to drive a real time embedded system(Say motor or LCD)on USB? Does anyone know of any commercial application of USB in Real time system? As far as I  know whatever USB applications we see in today's market(e.g camera,flashcard,Scanners etc) use USB for data transfer and not for...
  17. shekhar_dandya

    Simple battery charger

    Hi All, I think the voltage rating and the charging current to be applied is written on the battery.It is recomended that charging current should not be  exceeded. Why not design a constant current source,so that the charging current does not exceed?Why people go for constant voltage source? A...
  18. shekhar_dandya

    What is an electric field?

    How are they different? my question again, How does the capacitor works?
  19. shekhar_dandya

    What is an electric field?

    So,If we consider electrons as particles,then is the energy stored as potential energy in electrons? When the battery pushes the electrons from the -ve terminal(i.e electrons start disssipiating their potential energy aquired from battery charging),those electrons gather on one plate of...
  20. shekhar_dandya

    basics of electrical supply

    Hi, Iam back again with my original question. Suppose I remove the ground plate that's buried under my building in a 5 feet deep ditch.keep the earth terminal floating in air.ie don't use it. Now expt #1: I hold the live wire.Do I get a shock? expt#2:A person besides me on the same ground now...
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