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  1. Hero999

    how many 10v leds for 230AC and a few other questions.

    If you can connect the LEDs directly to 12V without blowing up then they have built-in resistors. ;D To test this non-destructively I'd connect the LED to 12V in series with a 1k resistor and measure the LED's voltage, if it's about 2V then there's no series resistor, if it's much higher, about...
  2. Hero999

    Solar powered Light

    I had an idea when looking at the Joule Thief circuit in the other thread. I thought, it should be fairly easy to convert it into a solar powered light by adding a few components. When light shines on the solar cells, the battery charges and when it's dark the Joule Thief circuit fires up...
  3. Hero999

    VOLTAGE DOUBLER

    The peak  voltage is simply doubled each stage minus two diode voltage drops. For 12V should should expect 32.8V, 65.6V and 131.2V. If the capacitors are small then there'll be lots of ripple so the output voltage will be much lower than expected. What are you having difficulty with?
  4. Hero999

    how many 10v leds for 230AC and a few other questions.

    Some power LEDs consist of many LEDs internally connected in series giving a higher overall forward voltage. http://www.rapidonline.com/netalogue/specs/56-0196.pdf
  5. Hero999

    how many 10v leds for 230AC and a few other questions.

    It depends, LEDs are normally constant current devices unless they already have a built-in current limiter. How much current do the LEDs need? For 12V just buy a wall adaptor.
  6. Hero999

    How to read electronic components using a multimteter.

    Please provide more information.
  7. Hero999

    VOLTAGE DOUBLER

    What's the meter's maximum voltage rating? Most meters are rated to 2kV and will be ruined if connected to 3760V. Did you measure the input voltage with the meter? What frequency is the meter rated to? A typical multi-meter is only designed to measure low frequency AC,  normally 50/60Hz...
  8. Hero999

    1.5v to 5v

    It's just a simulation. The peak current will be at least 6.67 times the output  current Although components can pass higher peak currents than the continuous rating the voltage drop will be hgiher so it's a good idea to overrate. Use a transistor with a higher current rating than the one...
  9. Hero999

    1.5v to 5v

    I have an idea but it will fail your 'not more than 1A' requirement as it doesn't have current limiting. Are you aware that 5V@1A out means [email protected] in? You've really set some impossible requirements, just buy an IC and be done with it. Here's my idea but it won't be very efficient, LTSpice...
  10. Hero999

    74188, 74287, 74288, 74387

    No wonder you found it hard to find the datasheets, they're obviously long gone obsolete. Use a more modern RROM or EEPROM.
  11. Hero999

    Simple FM transmitter question/s + help

    You've got the area calculation wrong. It's the cross-sectional area = πr2 I make it 213nH for  N = 6, r = 3 and l = 6 L = (1.2566
  12. Hero999

    Design new 0 to 30V power supply.

    That doesn't matter someone will probably build it sooner or later. I might even do it myself if I come across a free or very cheap 30V transformer.
  13. Hero999

    three component RF detector

    Do you want it to be self powered? Here's the simplest solution: http://www.electronics-lab.com/forum/index.php?topic=19564.msg89905#msg89905 It's not very sensitive and will only work if you're really close to a transmitter.
  14. Hero999

    AC power outlet

    Why do you keep posting random comments?
  15. Hero999

    Simple FM transmitter question/s + help

    You've made a mistake with the calculations. I use the following formula to calculate inductance which is the same as the one on Wikipedia but converted to metric and multiplied by 1000 to give the answer in nH rather than
  16. Hero999

    The flashing Heart(i have some doughts)

    You is often shortened to U in an informal message, e.g. text speak, cards or instant messaging. I'd reduce the LED current to 10mA because they won't be much brighter at 20mA. The yellow LEDs can be connected in 21 strings of four in series, cutting the current again by a quarter. Assuming...
  17. Hero999

    Fm transmitter

    It depends on what you're doing. How good does the transmitter need to be? Is it just a simple listening device which only needs to be telephone quality or is for a singer's mic. which needs to sound crystal clear? If all you want to do is build a simply listening device a simple two...
  18. Hero999

    OOPS I droped my laptop PS in a bucket of water

    I don't see why you shouldn't be able to fix the wet laptop. Does it have a mechanical hard drive or is it solid state? If it's mechanical, dry it out and if you can get it to work, backup all the data and replace it. Don't even consider re-using the mechanical hard drive, even if it works...
  19. Hero999

    A cool project - Replicate Steorn's Orbo - A back EMF-less free energy motor!

    It all sounds like rubbish to me. If someone really figured out a way to make free energy, no doubt they'd keep it a secret and make enough money to take over the work. I wish Steorn the best of luck.
  20. Hero999

    Simple FM transmitter question/s + help

    If you use the coil winding formulae yto calculate the number of turns required for 150nH you'll discover that all you need to do is remove some turns. Indeed you could do it experimentally but it's easier just to calculate it.
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