Search results

  1. walid1

    How to distinguish between FM and AM transmitter circuits

    Yes, it is not Hartley it is colpitts I have not built this circuit, but I've found it within the ready-made examples in the program I'm not confident in the results because the frequency stops always at 50 MHz and does not exceed that value no matter how reduced the values of capacitors Here...
  2. walid1

    How to distinguish between FM and AM transmitter circuits

    The Circuit does not respond when I reduce the values of capacitors and inductor for higher frequency, but I am confident that you are true. Thank you and to  Mr. Hero999
  3. walid1

    How to distinguish between FM and AM transmitter circuits

    Good I've implemented Hartley oscillator using a simulation program multisim 10 the first figure was with 6v batt the freq = 1.15MHz as shown then i used 9 v batt: i had the same freq. please explain that thank you
  4. walid1

    How to distinguish between FM and AM transmitter circuits

    Why scientists not put the battery voltage in the famous expression used to calculate any oscillator frequency?
  5. walid1

    How to distinguish between FM and AM transmitter circuits

    Ok I get it, "AM is produced because the transistor's gain alters as the base current is varied and FM because the capacitance between the PN junctions also alters as the voltage varies. " BUT: FM is alters as the voltage varies, you mean the voltage of the voice signal, not the voltage of...
  6. walid1

    How to distinguish between FM and AM transmitter circuits

    Thank you Hero999, you helped me Like this circuit? Another question: Why the transmitter frequency change when the battery goes down, despite that the calculation of LC tank frequency does not doesn't take the value of the battery into account? thank you alot
  7. walid1

    How to distinguish between FM and AM transmitter circuits

    hi please look at the following circuit, the author claim it is AM transmitter: it is from: http://www.zen22142.zen.co.uk/Circuits/rf/amtx.htm it is look exactly FM Transmitter, the only difference is in the values of capacitors and coils!!! Is there another difference I did not watch? Are...
  8. walid1

    Is it a hartely oscillator??

    Please i didn't understand. what if we use a buffer circuit between? thank you KevinIV
  9. walid1

    LC tank circuit frequency

    Hi when you build a FM transmitter with  LC tank circuit the frequency is: f = 1/(2 pi square root LC) why then when battary goes down the frequency is altered in the receiver? thanks
  10. walid1

    Is it a hartely oscillator??

    Like this: http://www.talkingelectronics.com/projects/27MHz%20Transmitters/27MHzLinks-1.html i understand you the reciever sense the carriar if ther is a cariar it do somthing like moving forward if no carriar do somthing else. thank you guru
  11. walid1

    Is it a hartely oscillator??

    Thank you guru it is good and fast answer Now you this is only an oscillator niether AM nor FM what you think it used for? thank you guru
  12. walid1

    Is it a hartely oscillator??

    Is this circuit using a hartely osc.? if yes please answer these questions: 1- is the emitter resistor affect the frequency of oscillation? 2- this is a transmitter circuit, is it FM or AM and why? thank you very much.
  13. walid1

    question about symetrical swing

    VC or VCE?
  14. walid1

    question about symetrical swing

    Hi when i want to design a preamplifier using BJT and need to have a maximum symetrical voltage swing at the output, then two conditions must be satisfied: 1- VCE = 0.5 VCC 2- I (saturation) = 2 IC Is there other conditions must be taken into acount?
  15. walid1

    correct me please

    I wait
  16. walid1

    correct me please

    Hello When one design  preamplifier using BJT voltage-divider unbupassed Emitter config, one want max symetrical signal swing at the collector. To do this, VCE = 0.5 VCC & I (saturation) = 2 IC = VCC/(RC+RE) If I want a voltage gain = A, then A= RC/(RE+re), where re = 0.026/IE, so RC =...
  17. walid1

    a cap vlue????

    Rs in series with Zin
  18. walid1

    a cap vlue????

    Whick R Rs , Zin or both if both, in parallel or sereise?? thank you
  19. walid1

    a cap vlue????

    Hello I built an audio amplifier that has an input impedance of 12k ohm my source signal was 1 mV and internal resistance Rs=1.2K ohm what the suitable value of the  capacitor that must be inserted between? thanks alot.
  20. walid1

    How does this simple circuit operate?

    Thank you hero999 it helped me
Top