Jump to content
Electronics-Lab.com Community


  • Posts

  • Joined

  • Last visited


faizanbrohi's Achievements


Newbie (1/14)



  1. Does anyone knows dbm to mW conversion . the output power of The Transmitter is +10 dbM , how much will be it in mWatts . ???
  2. hello again , after a long time i am back , and this time i have found two new crystal controlled IC's that suffice my needs , MC2833 FM Transmitter and MC13136/35 and MC3362 FM Reciever IC's . These IC's are crystal controlled and i think they will be fine for my Radio controlled Car. But Will it Work good for DTMF . It think it might. Although motorola does not manufacture these IC's , but these IC's Are available here in Pakistan at a very Cheap Price of Less than a Dollar . The Main Pain in the Butt is finding the crystals and the Inductors Just right and since the Transmitter is low power i have to build a Power Amplifier of 1W/0.5W for it. The Schematics and pinouts are attached.
  3. okay 33 pins are NC which are not connected so this leaves only 67 , out of which 16 are output to led which leaves 51 pins out of which 16 are for DIN and DOUT which leaves 35 pins and out of which only 2 pins are for register select for brightness control and DCLK , the only question i want to ask is that the maximum rating of DCLK is 15Mhz and there is no min or typical value given , so since 15Mhz is maximum so i can drive it with a 1Mhz clock refrence using Timer TLC552 . That is the only question please helppp....
  4. you might have varactors in the opposite direction as in my circuit.
  5. no i think it is somewhat your pulse rate . ;D , like a ecg machine
  6. I am Planning to build a parallel port led dimmer using ti's TLC5904 which uses 8 data inputs for adjusting the brightness or in other words current . you can control upto 15 LED's using this IC . I know how to interface the parallel port But there is some complication in this is , i don't understand what is a DOUT For , DIN DCLK are used for input for brighness control , and there input will come from a parallel port , since a parallel port is a 8 bit ouput from a computer . i don't know why dclk is for , do i have give external clock pulse . here is the ic pinout tlc5904.pdf
  7. But if you can implement AFC on the reciever side , why not in the transmitter side . But i think for my project that radio is sufficient ,
  8. yeah i get it , this means the TX-500 will be rock solid transmitter if it is PLL Controlled . and one more thing the IC i have for the radio is a KA22425 and also it's equivalent CXA1618M , well the PDf is attached . i know it is not PLL Controlled but why it is stable . i also used it to check my walkie talkie and what do you know , it is quite stable also , it was also quite stable with my FM transmitters , i previously build . it also has a LED indicator to indicate if the channel is selected KA2245d.pdf CXA161.pdf
  9. Hello again , i have a question how can i implement a crystal oscillator i found on the net in my modulator and replace the LC circuit . the desciption and circuits of fundamental crystal oscillators and overtone crystals are given here http://hem.passagen.se/communication/txo.html One more thing how can i use it as a refrence oscillator
  10. Well The PCb Layouts for the power meter are made , now its time to prepare the board and practically test it . will update soon
  11. Still i must say that Toner Transfer method is the best , i have printed an adaptor which is 7 to 10 mil and with perfect results . Just using simple glossy paper , which just cost's nothing compared to the photographic method and an iron. i have also tried the Photoresist method but with not sufficient results. i still Stick with The Toner Transfer method . i will show some pics of the board in the next post.
  12. Well here is the schematic of the Power meter . i am feeling a little sleepy , will make assemble and develop the board for the oscillator and power meter , until then astalavista baby !!!
  13. WHy not use a step up boost voltage regulator , like the ti's UC2577 , but it has a bulky circuit and high amperage . i think a small step up boost voltage regulator with 0.5 A and 12 V regulation voltage would be ok . But then again why bother , and just connect the 12 Volt battery pack directly ;D
  14. So if i remove it , it will be ok for DTMF and if i remove it . it will work for voice. now i will post the power meter shortly. one more thing i am putting a 12V voltage regulator for both the VHF power meter and as well as the VHF Amplifer. is it ok.
  • Create New...