Recent content by badai

  1. badai

    IC problem

    I have serial cable consist of 4 ports(on pcb).........one of them cannot work(physical problem). My expectation is because of the IC on that port. So, how i can know this is because of IC problem? Is it enough to test it using multimeter and compare with other IC from different port??? Any idea
  2. badai

    detector prototype

    AA215 diode I used for the design circuit only. The real diode is 1N34A. How to calculate the gain defined by C8,R6 and R12? What does it means, VCO that operates out of frequency range? What is the purpose of TR3, is it used as amplifier too? Why it need used 4.7k
  3. badai

    detector prototype

    so what minimum frequency it shoul be detect? How the VCO in this circuit is formed? Is it same like in tune radio circuit? :-\
  4. badai

    design PCB using EAGLE

    actually i had finished my layout. i export the layout in bitmap file but the problem is the size become larger when i want to print it. how to make it actual size? i try print directly(without export) and i got the real size but it was positive layout. my lab can do only negative layout. how to...
  5. badai

    detector prototype

    as in datasheet if i'm using 2N2222 as my TR1, min. freq it will detect is 250MHz, so what is the maximum frequency(frequency range)?
  6. badai

    detector prototype

    how to calculate the cut-off frequency which has value 60Hz?
  7. badai

    detector prototype

    this is my latest schematic but still missing R17....... :-\
  8. badai

    detector prototype

    can you show me clearly which part i should place R17?
  9. badai

    design PCB using EAGLE

    (no components)
  10. badai

    design PCB using EAGLE

    layout on board
  11. badai

    design PCB using EAGLE

    this is the original one
  12. badai

    detector prototype

    if that kind of problem, i hope it can detect up to 200MHz until 300MHz, so i can use 2N2222 in this circuit isn't?
  13. badai

    design PCB using EAGLE

    as you ask MP, i move to this forum. It looks like the author missed R17 on his schematic, from pin 12 to ground like R23 on the other side.(AUDIOGURU said).....can you show me clearly, where it should be placed? ERROR: Sheet 1/1: no SUPPLY for implicit POWER Pin IC1P V+ ERROR: Sheet 1/1: no...
  14. badai

    current limiter and stepper motor ramp generator

    hello guys. i am doing stepper motor control for position and velocity( ramp generator) .i am using 8051 as the microcontroller. anyone know how to construct ramp generator for stepper motor? how is the connection then? does it an external circuit to the motor or it has to be connected to...
  15. badai

    detector prototype

    1- i just scatch back, is it like this you mean? 2- So if the phone operates up untill 1900MHz, which one is appropriate transistor(except BFR90A) from list you given? 3 - In my previous circuit ff i'm using pad 1(wirepad) to connect my antenna, is it will work for my antenna?
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