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  1. Hero999

    Guitar Aplifier

    Doryy, I don't know wht you're talking about.
  2. Hero999

    Guitar Aplifier

    Yes, that might help.
  3. Hero999

    Guitar Aplifier

    Try replacing Q5 and Q6 first, then Q3 and Q4.
  4. Hero999

    High Voltage Stun Gun

    Unfortunately the original thread is missing because the server crashed awhile ago causing all threads posted before February 2009 to disappear. 
  5. Hero999

    Current power supply

    http://www.maxamps.com/Power-Supply-30A.htm http://parts.digikey.com/1/parts/1207857-pwr-sup-12v-50a-sng-output-sws60012.html http://www.mpja.com/prodinfo.asp?number=16751+PS
  6. Hero999

    low cast emergency automatic light

    That's not completely true, it will turn on a little bit, just not enough to power the LEDs, they might glow dimly. I have a couple of possible solutions: 1) Replace the BD140 with a P-channel MOSFET, remove the 1k resistor and connect a 10k resistor across the bridge rectifier. 2) Omit the...
  7. Hero999

    Want a 4400uF 50WVDC Capacitor

    You won't find a 4400μF capacitor because it isn't a standard value. Capacitors are only normally made in E6 values (E12 if you're lucky), look up "preferred value' on Wikipedia for more information. Just use 4700μF, the chances are it's just a typographical error.
  8. Hero999

    low cast emergency automatic light

    There are hundreds of projects on this site. Please provide a link to the one you're talking about.
  9. Hero999

    low cast emergency automatic light

    How are we supposed to know when you haven't provided the schematic?
  10. Hero999

    Guitar Aplifier

    Did you use the same transistors or did you replace them all? It sounds like there's a problem with one of the transistors. Your speaker is quite old, Yugoslavia no longer exists. ;D
  11. Hero999

    Guitar Aplifier

    The voltages are all referenced to 0V. To measure the voltage between two points, simply subtract the voltage at one point from another. It's probably easier to use a calculator but LTSpice can do it for you. For example with this circuit: Set the simulation command to transient analysis and...
  12. Hero999

    switch problem

    Then the problem is with the Li-ion battery. Does it sometimes work, then suddenly stop working? It's probably a loose connection. Try moving the wires around or tapping it to confirm this. Check all connections, resolder any bad joints and tighten any loose terminal screws.
  13. Hero999

    Capacitor

    Capacitors should always be discharged before assembling a circuit. Connecting charged capacitors to a circuit is always a bad idea.
  14. Hero999

    final year project: a blind stick that uses different sensors, help needed

    You'll probably find that just sending a 40kHz sound out through one transducer and monitoring the intensity of the reflected pulse, will give unpredictable results. The intensity of the refection will depend as much on the shape object and its composition than its distance. For example you have...
  15. Hero999

    Guitar Aplifier

    You've probably noticed that there is no C13 or transformer in the schematic. This is because, to make the simulation run faster, I've replaced them both with V1 which is set to 42V as it is the voltage you said is across C13. I assume you're talking about the DC voltage? There are two ways to...
  16. Hero999

    resonant filtering

    If you're talking about EMC filtering then no, resonant filtering is no beneficial, it's harmful because tuned circuits can be excited leading amplification of certain frequencies. Resonant filtering is only used for tuning a circuit to a particular frequency, for example in a tuned radio...
  17. Hero999

    is there any type of sensor that . . .

    Good idea, it shouldn't be hard to add a lower case 'r'  for reverse. I think the idea is to mount the device to the underside of the gear stick. What about using an IR LED and an array of photo-transistors? Mount the LED on flexible cable and put the sensors underneath it. Ambient light...
  18. Hero999

    transmitter module help

    I wouldn't buy a module that doesn't have a datasheet. How do you know it's FM? It looks like a remote control transmitter. Are you sure it has sufficient bandwidth for voice?
  19. Hero999

    How much mW is a typical IR diodes used in TV remote?

    Looks good as long as you know that the maximum continuous forward current is 100mA which will typically output just 35mW so you'll need to use 200 to get the 7W of radient power you originally wanted. The half angle is only 17
  20. Hero999

    Guitar Aplifier

    You'll need to upgrade LTSpice's default transistor library. Back up the existing LTSpice/lib/cmp/standard.bjt Remove the .txt extension from the attachment and save it in the LTSpice/lib/cmp directory.. I've also included a picture of my LTSpice implementation of the circuit, not that Q5 and...
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