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  1. Hero999

    Fm transmitter

    Ideally you need a 5V regulator with a drop-out voltage <1V@50mA will do. As I said before you could use the LM7805 which has a typical drop-out of 1.5V@50mA but the battery will only last for about 8 hours. You can buy the LM2931AZ-5 from Futurlec which is based in Thailand and ship...
  2. Hero999

    My latest PCB.

    Attached are some pictures of the PCB for a noise generator I'm currently building. I used the toner transfer process with magazine paper. For the silk screen I covered the toner with a thin conformal coating to stop it from being scratched off. It isn't perfect but it's good enough for me -...
  3. Hero999

    Fm transmitter

    True a 9V battery with an open circuit voltage of 6V can't produce much current, however when the regulator is connected the open circuit voltage is unimportant. For example, suppose the battery is discharged to the point where its open circuit voltage is 7V but when you connect the transmitter...
  4. Hero999

    Laptop video out to custom LED array possible?

    Is it possible? Yes. Is it easy? No. Sorry I'm not the bet person to help you with this.
  5. Hero999

    Fm transmitter

    The LM2936-5.0 will work down to 5.2V. The LM7805 will work down to about 6.5V with a low current load.
  6. Hero999

    re tv antenna amplifier fm/uhf/vhf

    I thought every project you've built worked first time. :P
  7. Hero999

    re tv antenna amplifier fm/uhf/vhf

    What preamplifier are you talking about? Please post a schematic?
  8. Hero999

    Fm transmitter

    You can use the LM78L05 if you like but the battery won't last as long.
  9. Hero999

    Fm transmitter

    I told you about the problems with that circuit before. You haven't even answered my question. I give up, you're on your own, as you don't seem to want to help yourself, I don't see why I should help you.
  10. Hero999

    not able to upload images

    I discovered this a couple of days ago, sorry for not reporting it to the administrator. Use a image hosting site such as www.tinypic.com
  11. Hero999

    Fm transmitter

    Which components can't you get hold of? It's possible to substitute some of the components. Rapidshare has limited downloads per day unless you pay, for images use www.tinypic.com which has limitless sownloads.
  12. Hero999

    CPU..

    mey alum nignog si. un pigo sog fin workin 4 u pwp up proply wiv u so pwr led.
  13. Hero999

    Fm transmitter

    500m through what? Free space, a forest or town? What receiver are you using? A cheap Chinese FM radio won't be able to pick it up from as far away as well as a state of the art car radio. What aerial are you useing? A high gain yagi array will transmit/receive the signal from a long away but...
  14. Hero999

    Fm transmitter

    I've already done that, read my first reply to this thread.
  15. Hero999

    Single PCB Production

    Whilst the sharpie pen will work, I wouldn't recommend it because it's very time consuming and doesn't give very good quality boards. I would recommend toner transfer. Print the artwork using a laser printer, iron it to the board using an ordinary clothes iron, soak in water and remove the...
  16. Hero999

    a few questions about Digital Step-Km Counter circuit/help

    Who's RED? Yes, use a magnetic speaker. I'd be tempted to get rid of R6 and use a 64Ω speaker or magnetic sounder.
  17. Hero999

    a few questions about Digital Step-Km Counter circuit/help

    I see, it's a Schmitt trigger oscillator. The trouble is, it isnt' the correct way to drive a piezo which is a capacitive load. You ideally need a push-pull driver, otherwise it will be very quiet indeed. As drawn, there is nothing to discharge the capacitive piezo transistor so it won't do...
  18. Hero999

    a few questions about Digital Step-Km Counter circuit/help

    Sorry, I can only answer questions 2 and 4 because the others are very poorly worded and don't make any sense. 2.why pin"14" of IC2 is grounded by C4? C4 is a supply bypass capacitor, it reduces the impedance of the supply to higher frequency. Digital circuits tend to draw brief high current...
  19. Hero999

    i need help in my Power Electronic project

    Sorry I can't help you, I've just had to Google MPPT. It sounds like a very interesting project though.
  20. Hero999

    Need Help Buiding the project using lm386

    I don't know where you heard that but it seems wrong to me, perhaps it's foreign? It certainly isn't English. Normally the letter R is used if it isn't possible to use Ω, for example: 22R = 22Ω, 2R2 = 2.2Ω and 0R22 = 0.22Ω. For larger values the prefix can be used instead of the decimal place...
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