Captret - Capacitor and Electret

[broli]

@nievesoliveras: ignore that drawing fully the original.

Also polarity matters, and a larger capacitance increases the brightness, went from 47µF to 3300µF.

[ibpointless2]

Thanks, I managed to replicate it and it's quite interesting. Actually you don't need to use both main legs of the cap, it also works like seen below.

There's obviously no short between the top cap and legs so that's ruled out. However my friend suggested it could be picking up radio waves. I want to rule this out by putting it in a faraday cage tomorrow.

I knew you could do that, i found out by accident when switching capacitors. I find it doesn't work exactly the same when you do it your way, it like the capacitor is not even there. 
hmm you got it working from the top to the -, i usually go from top  to the +.


I don't think its picking up radio waves.

[ibpointless2]

I tried a capacitor with a dead 9v battery and a led. It has not worked yet. I will let it connected a few days and see if the battery gains a charge.

The capacitor is a 2200uf 16v I took from an old motherboard. the battery had 2v when I connected it to the circuit.

Jesus

Your dead 9 volt battery is too low! it needs to be a "fresh" dead 9 volt that has at least 7 volts and up. For best results you should use a series of dead 9 volts that equal around 20 volts. The captret loves voltage. You might also want to try a lower farad capacitor too, i used a 1uf @ 400 volt capacitor for mine.

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I also make note for those who are having trouble replicating the circuit.

Your capacitor must be pre-charged first, and by that i mean the - and the + of the capacitor must be charge from the battery your going to use or a battery with the same voltage before connect everything up. Just a quick tap of the leads of the capacitor to the connection of the battery will do. Basically what you need is a capacitor that has been used before or at least charge up a new capacitor before connecting it all.
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But yeah your voltage is too low. You can use AA's if you want but the voltage of the batteries in series must be higher than 7 volts, 20 volts is preferred.

[nievesoliveras]

Thank you for the tips @bpointless2!

[broli]

Your capacitor must be pre-charged first, and by that i mean the - and the + of the capacitor must be charge from the battery your going to use or a battery with the same voltage before connect everything up. Just a quick tap of the leads of the capacitor to the connection of the battery will do. Basically what you need is a capacitor that has been used before or at least charge up a new capacitor before connecting it all.

This isn't the case with mine. In fact I just noticed it works equally well if you short the 2 legs together. Btw I'm using a new 23A 12volt battery.