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  1. S

    Flickering flame simulation with PIR motion sensor - mostly need help with transistor, I think

    I tried adding a resistor to your circuit to slow the charging of the capacitor but for some reason the LED does not fade on (only off)? Any idea why that is?
  2. S

    Flickering flame simulation with PIR motion sensor - mostly need help with transistor, I think

    Well slap my head and call me Sally! I didn't realise that was how it worked! This also doesn't make sense though! Now when I increase the voltage to the base of the transistor, the LEDs get dimmer. That's the opposite of what it should be?
  3. S

    Flickering flame simulation with PIR motion sensor - mostly need help with transistor, I think

    Thanks again. I don't think the transistor in the simulation is working right though. If I give a base-emitter voltage of 2.6 V, the transistor still doesn't fully open? This isn't right for a 2N2222 is it?
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    Flickering flame simulation with PIR motion sensor - mostly need help with transistor, I think

    Thanks. A pi? Do you mean a Raspberry Pi? I'm not using one of those but the output from my sensor is 3.3 V. Is what what you mean?
  5. S

    Flickering flame simulation with PIR motion sensor - mostly need help with transistor, I think

    Do you know what program that is? I know you said the resistor values are too high but why won't this work with only one transistor?
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    Flickering flame simulation with PIR motion sensor - mostly need help with transistor, I think

    Yeah, I made a mistake with my design. Thanks for catching that! Does 10F mean 10 uF or 10mF? Not 10 whole farads, right? How does a darlington transistor do this differently? Thanks again.
  7. S

    Flickering flame simulation with PIR motion sensor - mostly need help with transistor, I think

    After some more calculation, I think the capacitance should be lower. Here's an updated schematic: I just need to know the voltage drop over the 2N2222 when it's fully open with 6 V and ~210 mA. Is it negligible? Edit: Yes, the drop will be between 0.3-1.0 V between 150-500 mA so there's no...
  8. S

    Flickering flame simulation with PIR motion sensor - mostly need help with transistor, I think

    Thank you for this refinement! I will use just one flickering LED in each row. I want to add a small complication to my circuit in that I want the LEDs to fade on and off initially, a little bit more like an actual flame coming on. I've prepared the following circuit diagram using the power...
  9. S

    Flickering flame simulation with PIR motion sensor - mostly need help with transistor, I think

    I have (what I think is) an old oil lamp that used to be my grandmother's which was converted to electric and it has a flickering flame bulb which I think uses neon. The problem is that the light is so dim that it's essentially useless and only serves as a decoration. I wish to use flickering...
  10. S

    Highest density RGB LED strips that aren't addressable?

    Hey Bob, thanks for looking. Unfortunately those LEDs are fixed colours whereas I'm looking for RGB LEDs.
  11. S

    Highest density RGB LED strips that aren't addressable?

    It's possible to buy LED strips at a density of 144 LEDs per metre but the ones I can find make the LEDs individually addressable which is not necessary for my application and complicates control. Is it possible to get 144 LED/metre strips without indivudally-addressable LEDs (i.e. contacts for...
  12. S

    Two fluorescent tubes turned off at the same time - likely cause?

    After spending over an hour with the whole unit switched off, all the tubes are lighting again. At the moment I'm guessing that a temperature sensor was triggered but I'm not really sure.
  13. S

    Two fluorescent tubes turned off at the same time - likely cause?

    I was concerned that maybe some component had caused both bulbs to fail and changing/swapping them might immediately destroy the new bulbs also. I will try swapping the potentially defective tubes with the known-working tubes as soon as possible (tomorrow) to determine what works and what...
  14. S

    Two fluorescent tubes turned off at the same time - likely cause?

    I have a SAD lamp that is shown here. It has two halves, each of which contain two fluorescent tubes. One half of the unit switched off suddenly during use while the other half remains lit. What is a sensible response? Does one tube likely need to be replaced or both or something else?
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    Importance of low-ESR capacitors in dynamo rectification circuit?

    Thanks again, Harald. I'll go and read that link as well. I already have some zener diodes I salvaged from elsewhere that I might be able to use to allow me to use the 16 V capacitors that I have.
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    Importance of low-ESR capacitors in dynamo rectification circuit?

    I have another question! Why is the voltage specified so high given the application? The advised voltages for the capacitors for a circuit driven by a hub dynamo is 35 V but given that the application is lighting LEDs, the voltage should never be anywhere near that high. Wouldn't 16 V capacitors...
  17. S

    Importance of low-ESR capacitors in dynamo rectification circuit?

    I see. Thanks, Harald!
  18. S

    Importance of low-ESR capacitors in dynamo rectification circuit?

    The description of circuit 6 on this page says that low-ESR (equivalent series resistance) capacitors should be used for the rectifier - what would happen if capacitors were not low-ESR?
  19. S

    What if I try to charge battery with too-little current?

    Okay, thanks Harald. I'll buy a different power bank.
  20. S

    What if I try to charge battery with too-little current?

    I'm intent on using a crappy little wind turbine I'm making to charge a USB battery using something like this voltage regulator that will step the voltage up or down depending on what it's provided with. My question is if I could use the 12V version to charge a battery which expects to receive...
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