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Everything posted by trigger

  1. Have you check the output of your circuit to see if it really TTL signal or a ruined signal?
  2. A carrier will help to transmit further
  3. I think it is about the money! Say for example, a tradition 12V DC adaptor is around US$1.2 while a smps is 2 to 3 times or more in the cost, so as the importer or as customer, what will you choose?
  4. HDD needs stable voltage and I think LM317 is not appropriate in supply voltage to your application, esp. you can't guarantee the resistors values are stable.
  5. They are the substrate or say the materials used inside the PCB. For finished copper weight, if you are working on RF, the thickness of copper will affect the dielectric coefficient of the PCB.
  6. I will use solder iron to make them shrink, if I don't have the heat gun
  7. trigger


    You can use Izarc instead of winzip and winrar. www.izarc.org It is a freeware, so enjoy the "free" stuff.
  8. What I know is, some products keep a resistor footprint for adding EMC components for Lab test while they will use a 0ohm resistor for shipment product...... what for...... reduce cost :P
  9. Or simply say, don't use an RF transmitter near your head :P :P
  10. It acts like a small inductor in some cases.
  11. Sure, RF's influence in human's health still not determined. Who knows..... But one thing is, if I have a child, I will not use any RF devices near him/her. There is also some similar product to bluetooth, like zigbee. But I don't think it will be another technology trend. I am waiting for UWB wireless USB, where I think in the following few years, it will be a very hot topic.
  12. If it has a crystal, it is a superheterodyne receiver with local oscillator, typically 10.7MHz. It is much stable than the super-regenerative receiver. But I can tell if the layout and circuit is fine-tuned for the regenerative circuit, it won't do any significant differences in performance with heterodyne one.
  13. It is normal, you are measuring the off load voltage and it will be higher than the rated voltage.
  14. Try to give a 75 ohm load as some instrument need a loading. If it still not working, try to pass video signal through a capacitor. Hope this help.
  15. Also need to take precaution on the input capacitor, as it will affect the input signal.
  16. You can try using a transistor at the 555 output pin for switching and tie the blue LED to 6V with a resistor.
  17. Agree to audioguru. RF never been easy. Also many parts in cellphone already be BGA type ICs with unknown pinouts, no way for home builder to disassemble and using... ::)
  18. I think what you have to do first is to think of how to interface those items: keypad, alarm, camera, door lock to the computer. Be honest, if you are using a computer to do the work, everything are far too easy; only you need is to how to write program for interfacing. And mostly, "google" can help you a lot!
  19. I think it would be better to work on a DC/battery powered project first if you have no idea on electronics/electric.
  20. Try to use a text editor to open it first and check the header see if the file belongs to which program.
  21. I think what you have to do is to consult your professor or supervisor. Because mostly you have to do projects to please them rather than us. Right? :P
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