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  1. S

    Want to increase brightness of LED headlight

    Thanks! I didn't think about the high frequency draining the capacitor. Is there nothing else I can do to smooth the current in lieu of a capacitor? I might be able to use an oscilloscope at my local Hacklab/Maker space to measure the current.
  2. S

    Why isn't this image showing up?

    Does it work if you try to insert it into a post? It appears as normal in the editor mode but after submission it turns into that icon with a cross. It's the second or third time I've noticed it and I think it happens with images hosted on Imgur. Here's a random picture uploaded by someone else...
  3. S

    Want to increase brightness of LED headlight

    Thanks. I'll try to find larger inductors to test. I forgot to include the capacitor in my diagram which I think helps stabilise the current measured (updated diagram attached). The current is measured immediately before the LED. Do I need to consider the frequency of the circuit to choose a...
  4. S

    Why isn't this image showing up?

    http://imgur.com/ml4OtBM.png
  5. S

    Want to increase brightness of LED headlight

    I have the QX5252F IC and it's in a circuit where it increases the current to the LEDs up to 29 mA depending on the inductor used but there seems to be a lot of current bypassing the LEDs, going through the QX5252F. Is that normal? My inductors are cheap, low power, moulded axial ones. Are they...
  6. S

    Where to count legs from for TO-94?

    Is it customary to print labels on the backs of TO-94 packages? So the beveled edges are on the back? So the flat unlabelled side is where I should start counting the legs from the left?
  7. S

    Why are mains plug pins usually made of brass in the UK?

    Someone told me that brass has eight times higher resistivity than copper. Do plugs elsewhere use plated copper?
  8. S

    Why are mains plug pins usually made of brass in the UK?

    Why are mains plug pins usually made of brass in the UK? They're usually a silver-coloured metal in other countries, right?
  9. S

    Can an old Ni-Cd battery charger be used for Ni-MH batteries?

    Okay, thanks. Have you any idea what it only charges if two batteries are charged at the same time? It's a little inconvenient when some devices use an odd number of batteries and I wonder why they would design the unit that way. I guess it was just cheaper than providing for less frequent loads...
  10. S

    Can an old Ni-Cd battery charger be used for Ni-MH batteries?

    Say you wanted to charge 1500 mAh batteries (to make the calculation easier) with 150 mA, wouldn't you expect it to take longer than 10 hours due to the energy loses? 1500 mAh is ideally what you get out of the battery, right? So it must take more current to charge fully, right?
  11. S

    Can an old Ni-Cd battery charger be used for Ni-MH batteries?

    I have a socket timer that I can set to cut power after the required charge time.
  12. S

    Can an old Ni-Cd battery charger be used for Ni-MH batteries?

    I have an old Vidor model RX PC battery charger which is for charging Ni-Cd batteries. It charges at 150 mA for AA, 50 mA for AAA and 10 mA for 9V/PP3. Can it be used to charge Ni-MH batteries? If not, can it potentially be modified to do that? It just seems a waste to discard it if it can still...
  13. S

    Could a consumer electrical power meter measure power used by a dehumidifier?

    I want to be able to measure the average power used by a dehumidifier. Could this kind of power meter do that? I've read that they may not be accurate for "reactive loads".
  14. S

    Would variations in weather temperature shorten life of LED bulb?

    I was considering replacing the bulb in my mother's outdoor lantern with an LED one. Will the driver circuitry in the base of the lamp be adversely affected by the yearly variations in temperature (country is United Kingdom)? I'm not sure what kinds of components are usually found in the base of...
  15. S

    Want to increase brightness of LED headlight

    Oh I see, thanks. The frequencies seem really high so am I right in thinking a small ceramic capacitor would smooth out the peaks so the LEDs wouldn't see large currents? Also I think I would need to use two ZXSC380 chips in parallel to provide the current I want to both LEDs? Could they share a...
  16. S

    Want to increase brightness of LED headlight

    Thanks! I'll be sure to check the inductor specifications for saturation currents; there's one series I'm thinking of using which have currents in excess of an amp. It occured to me that the two LEDs must be in parallel in which case they might be able to take 40 mA total and not just 20 mA so...
  17. S

    Want to increase brightness of LED headlight

    I'm using cheap alkalines but I want to use rechargeables because then I don't need to keep remembering to switch it off when I don't need it, Fancy Energizer batteries sound relatively expensive but I already have a few rechargeable AAAs that aren't in use. I think I can use an SMD inductor. I...
  18. S

    Want to increase brightness of LED headlight

    I have one of these magnifiers and they're sort of almost useable at 2.5x but the light isn't very bright at all. I attached my bench power supply and determined that at 3.6 V a current of 20 mA would flow which is my guess at what the LEDs are rated for (maybe it's not; all I know for sure is...
  19. S

    What is this weird plug/transformer?

    But it's not a wart! It's vissible in the video immediately behind the probes and connector (which is being probed). I'm familiar with wall warts but they're usually pretty chunk and this is pretty not [chunky]! In the video I tested with the DMM set to DC first and then switched to AC...
  20. S

    What is this weird plug/transformer?

    I have an electrical plug and I don't understand what it's all about. It looks a lot smaller than a transformer usually does and although it says DC5 on the side, I outputs about 4.8 V AC. If I wanted to find out about its use what would I need to type into Google? What usees 4.8 V AC? I have...
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