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Everything posted by Shahriar

  1. Hi One of my friends has uploaded this Journal in the link Below. I Put it here. Maybe others like it. http://www.4shared.com/file/1212367/9d46f8df/elektor_january_2006.html PASSWORD = vampire ُShahriar
  2. Hi I have an OpAMp (NE5532) which is driving a Headphone. I want to add a Mute System to this circuit. How is it possible whether it has a Dual Supply or single Supply. (If it differs) ThanX in advance Sahriar
  3. Thank you very much for your reply. Master Should send Data to all slaves and Retrieve some data from each Slave. Just like a I2C Bus System. But the difference with this system and a Small I2C Bus System is Distance between Master and Slaves. BTW, Each Slave is a MCU Based Circuit. ThanX Shahriar
  4. Hi I am designing a new Language laboratory System. I want to send serial data via a Common bus to all Stations (Students devices). The length of this bus is around 20-25 meters. Which method is the best for transferring Data. I mean FSK, RJ485 (if I wrote it right), SPI (that I don't think it work) or ... The Baude Rate is Around 9600 bps ThanX in advance Shahriar
  5. Hi Can anybody tell that why Sink Current in most of Integrated circuits are higher than Source current. i.e. a TTL Gate can sink around 20mA while it can not source more than 10mA. (The Numbers I said are not very sharp.) ThanX Shahriar
  6. Hi Follow the links below. when you downloaded all 13 links, then extract number one to creat a PDF. This book is in 877 pages and one of my friends has uploaded it. http://www.4shared.com/file/811501/4b4cfb69/OpAmpApplicationsHandbook__2005_part01.html http://www.4shared.com/file/811525/7e175df2/OpAmpApplicationsHandbook__2005_part02.html http://www.4shared.com/file/811529/77a111d9/OpAmpApplicationsHandbook__2005_part03.html http://www.4shared.com/file/811534/100b5c25/OpAmpApplicationsHandbook__2005_part04.html http://www.4shared.com/file/811536/fe053d09/OpAmpApplicationsHandbook__2005_part05.html http://www.4shared.com/file/811539/6eba2098/OpAmpApplicationsHandbook__2005_part06.html http://www.4shared.com/file/811618/29cdccd5/OpAmpApplicationsHandbook__2005_part07.html http://www.4shared.com/file/811636/fc438350/OpAmpApplicationsHandbook__2005_part08.html http://www.4shared.com/file/811645/2a0b442d/OpAmpApplicationsHandbook__2005_part09.html http://www.4shared.com/file/811666/81347715/OpAmpApplicationsHandbook__2005_part10.html http://www.4shared.com/file/811681/81d3cf38/OpAmpApplicationsHandbook__2005_part11.html http://www.4shared.com/file/811795/9e675057/OpAmpApplicationsHandbook__2005_part12.html http://www.4shared.com/file/811798/e0d62cea/OpAmpApplicationsHandbook__2005_part13.html It is a complete book HTH - Shahriar
  7. Maybe using CD4066 or CD4016 solve your problem. of course depending on Your current and Voltage as Staigen said. HTH - Shahriar
  8. The best way for a RPM counter is What pebe Said. Imagine if you use a Devider or revs in say 10 sec and then calculate for 1 min this problem will happen! You should multiply the number of RPM in 10 seconds by 6 to achieve for 1 min. so the Number you achieve is alway = 6K. I mean : 6 - 12 -18 - 24- ... 6K (Sorry, I don't know the english name) So if you have a real RPM = 15 then your device will show 12 or 18 And another problem is your counter will be refereshed every 10 seconds. If you decrease this interval (10s) then you should multiply it with a bigger number and ..... :o :o HTH - Shahriar
  9. Hi I want to build a Video Multiplexing device, Which can show a single video picture on a big screen which has been consist of 4 or 16 or more single screens (CRT or LCD). I have tried to show what I mean in the attached picture. This project is just like those in TV SHows that show the Singer picture on a very big display. Can anybody tell me the theory of this device. Or any related Note on the web? ThanX Shahriar
  10. Yeah, Thats right. but for using a Scanner, you need a PC for every one, and every few minutes you should put that Heavy book in the Scanner. Sometimes, There are lots of solution to do a job, But I think the important is which way is The best. If you yourself were in a library and you could choose between a Scanner and this device, Which Would you choose.... ::) ThanX Shahriar
  11. BTW, If you don't want to build one, You can buy a Mobile Charger and enjoy it... HTH - Shahriar
  12. Hi The circuit I have attached is from a Project in project section of this site with this topic. " Courtesy Light " you can use the power section of this project with some changes. Once I saw a project on the web with this title." Transformerless Power supply" as I remember it has did the same trick. HTH - Shahriar
  13. Hi Have you ever gone to a Library, and when you are reading a book, you need to take some notes of the book. You have probably found it disgusting! The Problem is worse, when there is a picture in that section. If there was a device which you could take it to library, and when you need to take a note, you just put it on the book and drag it over that section to save that part in Memory. Then when you came back home, you could upload it in PC and do everything you need! What things you should do to build such a device? ThanX Shahriar
  14. Hi I have a 433MHz TX and RX module which you should connect it to a 50ohm Antenna and enjoy! I plan to use a i.e. 1W RF amplifier to increase the output power. Does any body have a Schematic for this Power amplifier ThanX Shahriar
  15. Hi Imagine that you want to build an Inverting OpAmp Amplifier with the Gain of 30. What is the difference if I choose two resistor as (Rf=100K, R1=3.3K) or (Rf=10K, R1=330R). In both cases the Gain is 30, but In what conditions, does it make difference? and what about a Non-Inverting One? ThanX Shahriar
  16. About the PreAmplifier I sent, I should say that, I do NOT think if it will drive a Speaker. The Output of this preAmplifer Should be connected to a Power Amplifier Like that 10W Amplifier in Project section as I said Before. I sent these, Because gogo2520 wants to build a descret circuit. HTH - Shahriar
  17. Once I see a Project which send and receive SMS via FBUS in a NOKIA Mobile, May be it could help you. If You look it up in Web, You can find it. BTW, I have seen some Devices on the web which can send a mass of SMS, While connected to a PC HTH - Shahriar
  18. I have Recorded and PlayBack Sound via ISD25XX ICs many times, But if you mean a video Clip, I should say NO, it is impossible with these ICs HTH - SHahriar
  19. Here the preAmplifier you need. Use Bias Resistor If you have an Electric Mic and remove it if you have a dynamic Mic. You can Find the Power Amplifier from the Project section of this site. It has used a NE5532 and a Push Pull at the output. I have built these two and works very well. HTH - Shahriar Precious_PreAmp_Kit.pdf
  20. I have not done this, but think about it.... Use a laser Pointer (Those use in Conferences) and fasten the pointer to the IR Tx. then Once you adjusted RX and TX when they are close to each other, then Mark the Laser pointer Somewhere on receiver. In this way you can adjust them in far distances... I hope I could write what I meant... ??? HTH - Shahriar
  21. Hi One of my friends (who has enough money) and I want to start a new job. we have disscused very much about what kind of bussiness we begin. At last we agreed to find a factory or company in another city or country(litttle bit difficulat) and tell them that we can sell their products and give after sale services in our city. My friend will take the responsibility of Selling and I will take the responsibility of Installation and Servicing. Of course I don't mean we will do all the job ourselves, we will also take some other qualified persons! Now my question is what kind Devices do you think is good to look for? i.e. Medical devices, TV & Audio Players, washing machines, Micro Ovens, Battery, .... ??? Your Ideas is greatly appreciated in advance Shahriar
  22. Hi In the following picture which belongs to a Tone Control Circuit, Can anybody tell me what that Small Value Cap (10pF) Is for? Between In+ & In- Pins I remind I saw the reason somewhere Once, but todayI looked it up in all my books, But did,'t find that. I guess it is some how related to OpAmp Input Capacitance? Thanx in advance Shahriar
  23. Hi In the following picture which belongs to STK4121 Power Amplifier IC, Can Anybody tell me what that 3uH Inductor at the output is for? In Car Power Amplifiers, there are some big Inductors wounded on a big Core, Are they the same as this inductor? ThanX in advance Shahriar
  24. Dear Staigen As I Know, they send digital Data! For modulating Sound, I think 100Khz for carrier frequency is a little low, Isn't it? Shahriar
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