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  1. Shahriar

    protel please help

    By the way there are Lots of these examples in Help folder of protel. Anyway here a one. LampFlashelSignal.zip
  2. Shahriar

    protel please help

    Dear Polka I have plenty of Protel schematics and its PCBs. what is the version of your protel? DXP or 99SE? Do you want to simulate it or draw the PCB? Because U can not simulate schematics Involving components which do not have Simulation...( I am not very fimiliar with Protel Simulation. and...
  3. Shahriar

    non-cassette answering machine

    Dear Maece I know a device that I guess it will help U but I am not sure enough whether it is the thing U are looking for or not If U explane a little about the answering machine U need, Then I think I can help U. Truly Shahriar
  4. Shahriar

    NEC TV goes to stand-by when searching for channels!

    Hi I Have a NEC 21" TV (model= MH5) and it goes to Stand-By after 10-12 minutes working in normal condition with perfect Image and it goes to stand-by very quickly in Auto-Searching mode but It doesn't go to Stand-by when the antenna is disconnected. I thought maybe sth. gets hot so I made...
  5. Shahriar

    Need Ic which can Enable Its outputs One by One!

    Yes! Using a series of D Flip-Flps. Tricky ;) ThanX - Shahriar
  6. Shahriar

    Need Ic which can Enable Its outputs One by One!

    Hi I need an IC (i.e. 74XXX Series) with 8 or more outputs. The outputs will be enabled on by on after each other when I trigger the Clock pulse Input. the important note is that the outputs should stay enabled until I reset the IC. ThanX in advance Shahriar
  7. Shahriar

    Want to use LED Dot Matrix Board

    Hi everyone I know how to use matrix displays an how to multiplex them but I have seen some of these boards in streets in very big sizes. the display animatimations. for example the word "NEC" will move in many directions with too many effects. how do they write the programs. Is there a...
  8. Shahriar

    Temp. Compensation for linear power supply

    Dear smartsarath2003 Put an ameter in series with your load to check how much current U draw from your regulator. putting a 220Ohm load in 24V draws just 110mA and in this case know heat sink is needed. I am sure that you have connect sth. wrong. specialy the pins of lm338 HTH - Shahriar
  9. Shahriar

    Help needed for Timer Circuit

    Dear gnipihz If I were you I would use a mcs-51 microcontroller (i.e. 89c2051). Its programing is vey easy and  U do not need any cpmlicated circuit. If U do not know programming U can ask a friend to write it for U but if U are a little bit inteligent U yourself can learn it in just three...
  10. Shahriar

    How to build a Hardware Lock?

    Hi I want to build a Parallel Hardware lock which can connects between Printer and PC Port. I would appreciate it if I could use a serial EEPROM to Store some data. Any schematic or Idea is appreciated in advance. ThanX - Shahriar
  11. Shahriar

    Long Range Remote Control (The problem of many People)

    Hi I Need a Long range remote control about 600 or 700 meters. No range Limit is in my area.I have some modules For those garage doors remotes. but their range is not enough, I made a try to make it by using that 4Watt FM Transmitter in project section but the frequency Of the ocillators...
  12. Shahriar

    4W FM Tx

    Dear Knownothing I have built the 4watt Tx and it wotks well. the only Transistor that gets hot is TR3 and needs Heatsink. The other Transistor tempreture is normal and is because of the Frequency they are working. But My Tx Problem is that its frequency sometimes changes when I Disconnect the...
  13. Shahriar

    Please Help Finding datasheet

    The Last on "TC9409BF" is SINGLE CHIP KARAOKE LSI". I found it in datasheet archive. maybe you can get more information about the others from http://www.datasheetarchive.com/ HTH - Shahriar
  14. Shahriar

    Coupling capacitors!

    Hi I Think this is why a Cap do not pass DC current... The current Formula in a Cap is as Follow: i=C dV/dt + v0 This formula indicates that we have current in a cap If the Cap Voltage Changes (The meaning of dV/dt). So If you just imagine DC voltage across a Cap...
  15. Shahriar

    If you are looking for good PLL FM Tx, Look at this Link

    Here is a PLL FM transmitter. I have not build it yet but I feel it will works nice. http://www.pira.cz/eng/index.htm Click on "FM transmitter 3 W" If it was in Cz Language, go to http://www.pira.cz/ and click English HTH - Shahriar
  16. Shahriar

    Have anybody Build that "4 Watt FM Transmitter " In projects section

    Dear Audiguru Would you please give an explantion that what are Pre-emphasis & de-emphasis? The DATA frequency coming out of PT2262 is about 7-10Khz and its Amplitude is too big(nearly 10V) so I decreased it with a 50K volume. 2-what is the diference between RFC and an ordinary Inductor...
  17. Shahriar

    Have anybody Build that "4 Watt FM Transmitter " In projects section

    Here My schematic
  18. Shahriar

    Have anybody Build that "4 Watt FM Transmitter " In projects section

    Hi I want to build an FM Transmitter to control two Realys. the range of the transmitter should be about 700 meters. I selected 4 watt FM Tx from project section I used PT2262 encoder to creat DATA. and schematic is as below. but some questions:"If you do not see any thing wrong" 1- Can I...
  19. Shahriar

    SERIAL PORT

    Dear MP Is it also true with LPT1 port. I mean: Is "Parallel port" short circuit protected too? I do not dare to check it out. Shahriar
  20. Shahriar

    SERIAL PORT

    Remember Two things: 1- Always connect your PC serial port directly to a buffer IC (i.e. 74245) because PC serial port is not protected from short circuit. 2- the other thing that many people forget is that the address of PC ports are in HEX, for example 370H, many people mistake it with...
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