Mysterious Resonant Circuit

[aleks]

"Singing" components is a trace of magneto or electro-striction. Note that acoustics can be in hypersonic range - in mega and giga hertz region, especially in crystals and metals. It's all magneto and electrostriction, even if not hearable.

Then again, your example of auto-varying sinewave frequency (kind of Earth's VLF spherics) is an example of "infinite sweep" where fedback Doppler shift happens - this can be produced if acoustics are at play, which is suitably "slow" to produce enough delay for such "effect".

[Grumpy]

a)   I measure the current with an ampmeter in series with the battery.   Reading is 0.1 amps  (Voltage measured across the battery is 8.2 volts,  both are DC measurements)

Battery Type           Capacity (mAh)            Typical Drain (mA)
D                           12000                          200
C                            6000                           100
AA                          2000                           50
9 Volt                      500                             15

Are you sure about the 0.1 amps?  0.01 sounds better.

[EMdevices]

Ok, here's the scope shots that I promised.

Figure 1,  my new arrangement.  (positive red wire is just hanging loose in this image) 
Figure 2,  output waveform at the 148.7 ohm resistor   (yes I measured it, whoever asked)
Figure 3,  look at that smooth voltage at the battery terminals !!    (Someone tell Dr Stiffler to use the same approach.)
Figure 4,  schematic,  I had forgotten this morning when I posted, that I used two branches of LC to smooth it even further.

I see my Voltage is a bit smaller more like 7 volts.  I had used my digital meter to measure it while in operation. This means lower input power so a higher COP.  Also, the amperage is 0.1 amps,  I did a sanity check with a simple resistor across the 9 V battery, just to make sure I'm not off by a factor of ten like it happened last year.  Grumpy you're so optimistic.  LOL

EM

P.S.  The scope shots file names have no relation to what is on the schematic, just go by what I wrote above, Figure 1 is the top image and it goes down from there.  I think it's self explanatory, but just in case somebody gets confused.
duff,  the toroid has 3 sets of windings, each 15 turns.  My added coil for driving the transistor base has 8 turns. Not sure what core type it is.

[Grumpy]

is the battery warm or hot to the touch?

EDIT:

I ask because a 9v battery is not meant to provide that much current.

example:

http://64.233.167.104/search?q=cache:gh9DLppHHW0J:www.powerstream.com/9V-Alkaline-tests.htm+9v+battery+0.1+amps&hl=en&ct=clnk&cd=1&gl=us

[xee]

@ EMdevices
I know that you know this so I feel stupid pointing it out, but why are you using a 1/4 watt resistor? Resistors change value when they get hot (which they get when run over power rating). To get good results you should use at least a 2 watt resistor. You should get the same results in your circuit but the question of what is the actual value of the resistor would not come up.