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  1. walid1

    switching diode

    Hi I'm here where are you..... I wait
  2. walid1

    Transformerless power supply discussion!

    Hi Audioguru First of all I thank you for your kind answer. you must complete the road with me to make me understand as you hope, so (1) The 1.6mA, I think you depend on my calculations to get this number, that is 1.6mA approx = 220Vrms/130.5Kohm, is this true? (2) If (1) is true, R2 must...
  3. walid1

    Transformerless power supply discussion!

    In the figure below you can see a transformerless power supply circuit, the component values are as follows: R1 = 220K
  4. walid1

    need help w/7-segment displays

    you need to explain your question more to have an answer
  5. walid1

    Identifying Low ESR Electrolytic cap

    What a LOW ESR type  means thanks walid
  6. walid1

    Inductor's colors - The same as resistors?

    Hi look at this link it may help you: http://www.electronics-lab.com/forum/index.php?topic=3911.0
  7. walid1

    switching diode

    I read this:"a small signal diode of the 1N914 type commonly used in switching applications". I know thast 1N914 like 1n4148 is a small signal diode but what are the switching applications, give me some example on how to use diodes to switch between ON and OFF thanks
  8. walid1

    Diodes as frequency multiplying devices in rf circuits

    Thank you very much Audioguru I understand it very well this is really good answer thanks again walid
  9. walid1

    Power transformer winding

    Hi Ante I found this very interesting thank you very much Walid
  10. walid1

    Diodes as frequency multiplying devices in rf circuits

    I read this statement somewhere in the web, can you please explain this with practical example circuit. thanks very much.
  11. walid1

    What this circuit do???

    Ok guys, I'll tell you the story I have a small telephone device, it is very simple, I try to understand its circuit, it contains this circuit in it, this is the 4069 IC. When I follow the diagram I found that pin 14 of 4069 which is the Vcc of the IC is connected to the phone lines via a cap...
  12. walid1

    What this circuit do???

    Hi all This circuit shown below consists of 6 inverters (NOT gates), that is using the 6 gates in 4069 IC, these gates are connected as shown with 5 resistors, 3 caps and one diode the o/p is as shown. can you please tell me what is this o/p. I think it is an oscillator, but it is very complex...
  13. walid1

    Impedance matching

    Hi autir I think you cannot achieve these extrem limits in practicle but i think to have a maximum power transfer the impedances between the stages must be equal
  14. walid1

    Choice of switching regulator IC

    i think this is not the problem..... A switched mode power supply (SMP) uses a ferrite core transformer, how you will get it . If I in place of you i get this psu from a used computer monitor and modified it , or simply analyze it and understand the design.
  15. walid1

    Choice of small signal BJTs

    There are many general purpose transistors like what audioguru said and 2n2222, 2n2907 i 'll tell you what i do; i get some electronic board from say radio or any other not used device and get all the transistors from it then get their datasheets and put them in boxes for future use. this makes...
  16. walid1

    picture under my name

    Yes, thank you very much. walid
  17. walid1

    Air coils winding

    hi friends here are you
  18. walid1

    Antenna

    Hi 1st Mil-Tech you mentioned a very important subjects, can you point me to any web pages that discuss these subjects tank you.
  19. walid1

    Air coils winding

    How the Q of the coil affected by its shape what is Q of the coil???????????
  20. walid1

    Dots in transformer symbols

    Where are you alun????????????????????
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