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  1. S

    Ampacity of brass/thickness of brass wire needed

    I have a couple of LED lighting projects using brass candelabras as their base. I want to use brass wire which I will enamel using polyurethane but I need to determine with minimum width of brass wire to use. One lamp will carry up to two amps on a single wire and the other, if it goes ahead...
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    What is special about solderable enamelled copper wire?

    This website lists their enamelled copper wire as solderable and I wanted to check whether some enamelled wires are more suitable for soldering than others? I know for sure that there are different kinds and grades of coatings but I'm not sure in what situations they matter.
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    LEDs in parallel don't consume sum of individual currents??

    I checked the currents that passed through several LEDs at a particular voltage. They varied from 12.0 to 15.1 mA at 3.0 V. I then connected them all in parallel and the current running through them was about 22 mA. How can this be? I thought it would be the sum of the currents that passed...
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    Multimeter giving bad voltage readings

    I've had a cheap Precision Gold Academy PG 10B multimeter since I was a kid (so it's about 20 years old) but just recently I've got reason to suspect the voltage readings. For my computer PSU it gives the 5 V rail as 5.8 V and the 12 V rail as 13.9 V. For my variable power supply it gives any...
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    What do people stick their self-adhesive breadboards to?

    I have a couple of breadboards and they both have spongy self-adhesive backings. Searching the Internet suggests to me this might be more common than not. What are people sticking their breadboards to?
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    Electronics modules names and why there are so many manufacturers of the same thing

    It seems like there are many different manufacturers of the PIR module HC-SR501 and this confuses me somewhat. What is the name "HC-SR501"? There's only one manufacturer of the Galaxy S7 and that's Samsung. Why is it different for the HC-SR501? Did the originator not patent it or is the patent...
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    That kind of photodiode to use for HC-SR501 PIR module.

    I'm using a "HC-SR501" PIR module to control a lamp I'm making for my hallway. As well as being motion-activated, I want to use a light sensor to only allow activation after dusk. The HC-SR501 comes with this functionality - you just need to add a suitable component at the right place on the...
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    Decorative wiring: enamelled copper?

    I'm making an LED candelabra and the wiring has to be visible because it's running along the outside of the candelabra. Is it a totally mad idea to use polyester enamelled copper for the wiring? I think it's the least aesthetically unpleasant option. Are there different thicknesses of enamel...
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    3.85 V li-ion battery to replace 3 V lithium cell in bathroom scales?

    I have a couple of old phone batteries which I would like to put to use and I have bathroom scales which use a single 3 V lithium coin cell. Would the electronics in the scales be likely to be damaged if connected to a lithium-ion battery? The scales have an LCD screen in case that helps.
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    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...
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    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...
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    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?

    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?
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    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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    Considering viability of project: small wind turbine for 5 V camping charger

    I'm considering making a small wind turbine to charge a 5 V 8000 mAh battery pack. The wind speed in target hills is typically 5-10 m/s. If it ever approached 20 m/s while I was there, I'd probably leave! I think I could use a stepper motor like this combined with a fan blade like this...
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    Advice for soldering long chain of RGB LEDs

    I have many 5 mm RGB LEDs that I want to solder together into a long chain. I want to make three chains of about 30 cm length. They will be hidden inside some frosted acrylic tubing so it doesn't need to look too pretty but it does need to be pretty straight. In this picture you can see the...
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    Calculator fault: certain segments aren't showing on LCD

    I have a Sharp EL-506V calculator and certain segments of the LCD figures are not showing. Is there a likely cause for this kind of fault?
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    Computer PSU failure - voltages low - damage sustained?

    A couple of weeks ago my computer would not boot (the fans all started but the power LED appeared to flicker). I measured some of the PSU (Thermaltake 705w 700 W, now eight years old) voltages and the 12 V output was 10.3 V and the 5 V output was 3.5 V. This is far outside of specification. I...
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    Electrical generation in power stations - how AC Hz and voltage fluctuates

    I was wondering how power supply characteristics fluctuate with variations in power generation and consumption. In some jurisdictions you can monitor the frequency (Hz) of the national power supply grid(s) and as consumption increases relative to supply the frequency drops. I was wondering...
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    Connecting USB outlets in parallel for more current draw?

    I want to use a lithium battery pack for a project. This one lets you draw up to 2.4 A, 2 A and 1 A from the different outlets. I would like to know whether I'd have any problem taking the power from each and connecting them in parallel so I could draw a maximum of 5.4 A (I'll avoid approaching...
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