mini-Tesla

[sanmankl]

@EMDevices and all,

What happens if I use an aluminium tube instead of plastic to wind the coil? I have some Redoxon vitamin tablet tubes and I'm thinking of using that instead of plastic pipe.

Cheers, cp

[EMdevices]

Hi sanmankl,

I'm not sure if an aluminum tube will work the same, since it's conductive and the capacitance will change your circuits operating parameters, voltage will not build up like it should.

For the colpitts oscillator part of the circuit, look at the photo.Ã,  See the two small green capacitors?Ã,   I don't have a LCR meter so I don't know what values thos things are, but if you have a box of capacitors, like I do, just try different values.Ã,  The coupling capacitors are not critical, they just need to have a larger capacitance then those two green ones.Ã,  The resistors are the same for the colpits 10K and 10KÃ,  so the bias point is V_bat/2, so it's biased at the midpoint to allow for maximum swing.Ã,  The mosfet has 10K and 1.5K to bias it lower in voltage.Ã,  Just play around and you'll get it.Ã,  The trickier part is the colpitts, if you got that to oscillate, you're ready for some fun.

EM

[EMdevices]

Update:

I made a power capturing board to test the filtering from the AV plug.

Very interesting results, but kind of discouraging.   I added one LED and the voltage before the resistors and diodes was approx 2.5 volts DC, with a ripple of 1 V AC getting past the filtering.

When I added a second diode,  the voltage went to 5 volts DC.

This almost shows that the DC current is almost nonexistent, and it's the AC voltage and current that really drives the LEDs. (since there is no voltage drop across the resistors and we just see the forward bias voltage of the LEDs)  I also connected a small screwdriver to one of the legs of the LEDs and it lit up so good and bright, so this also shows it's the AC that drives it.

Here's the pictures.  Notice I also have a compact neon leaning against the tesla coil and it's lit pretty good. There are no wire connections to it, it's just lit because it's in the RF fields.   

EM